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1
Brown, Charles R., and Mary Bomberger Brown. "The Costs and Benefits of Egg Destruction by Conspecifics in Colonial Cliff Swallows." Auk 105, no. 4 (October 1, 1988): 737–48. http://dx.doi.org/10.1093/auk/105.4.737.
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Abstract We studied egg destruction by conspecifics in colonial Cliff Swallows (Hirundo pyrrhonota) in southwestern Nebraska. Between 8.5% and 19.6% of all nests lost at least 1 egg to an intruding conspecific. Egg destruction occurred when nests were left momentarily unattended, often during colony alarm responses. Birds that destroyed eggs maintained nests of their own, and usually nested within 75 cm of their victims. Egg destruction was not related to attempts to usurp nests. Over a third of perpetrators of egg destruction lost eggs from their own nests to conspecifics. Egg destruction occurred more often in nests initiated early in the nesting season and in nests with large clutch sizes. Egg destruction usually occurred during a victim's egg-laying or early during incubation and declined in frequency as incubation proceeded. Breeding in a colony's peak period of nesting did not afford an advantage to potential victims by diluting their chances of being victimized. Cliff Swallows seldom destroyed all of the eggs in a neighbor's clutch, usually destroying only 1 egg at a time even though other eggs were present. There was little direct evidence that egg destruction was associated with parasitic egg-laying by Cliff Swallows, but nests with egg destruction were over 3 times more likely than nests in general to have an egg physically transferred into them. The costs of egg destruction to victims were obvious, but the benefits to destroyers of eggs were not. Egg destruction is possibly a prelude to physical transfer of eggs, reducing host clutch sizes and ultimately within-brood competition among host and parasitic nestlings. Males may also benefit by destroying a female's eggs during laying, thereby causing her to continue laying and remain sexually receptive to forced extrapair copulations. Incidence of egg destruction by conspecifics increased with Cliff Swallow colony size and thus, for potential victims, represents a definite cost of coloniality.
2
Sealy, Spencer G. "Egg laying in inappropriate nests by the Brown-headed Cowbird (Molothrus ater): acts of parasitism or emergency egg dumping?" Canadian Field-Naturalist 129, no. 1 (June 5, 2015): 60. http://dx.doi.org/10.22621/cfn.v129i1.1668.
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The generalist, brood-parasitic Brown-headed Cowbird (Molothrus ater) has been found to parasitize the nests of about 220 species, mostly passerine birds. Among the thousands of documented cases of parasitism are rare records of egg laying in nests in which the cowbird stands no chance of success, because its diet or developmental strategy are incompatible with those of the “host” species. Forty-four nests of 16 such inappropriate host species are reviewed: 23 nests of nine precocial species (waterbirds and shorebirds) plus 21 nests of seven altricial species (a raptor, doves, cuckoos, a hummingbird, and a woodpecker). Two hypotheses explain inappropriate egg laying. In the “normal laying” hypothesis, Brown-headed Cowbirds may lay dozens of eggs in nests they encounter, including the occasional inappropriate nest. In the “emergency laying” hypothesis, females, on discovering that a selected nest has failed, must lay or “dump” her eggs elsewhere, in nests of inappropriate hosts or already-parasitized nests of regular hosts. Support for either hypothesis will require electronic surveillance of movements of nest-searching and laying Brown-headed Cowbirds to generate fine-scale spatial data that confirm whether parasitism on inappropriate nests occurs at the usual laying time for pre-selected nests (around sunrise) or later in the day if the chosen nest has failed and emergency laying is required.
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Maddox, J. Dylan, and Patrick J. Weatherhead. "Nests Without Eggs: Abandonment or Cryptic Predation?" Auk 123, no. 1 (January 1, 2006): 135–40. http://dx.doi.org/10.1093/auk/123.1.135.
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AbstractWe determined whether nests that did not receive eggs was attributable to cryptic nest predation (i.e. predation of eggs laid between nest checks) or nest abandonment in Common Grackles (Quiscalus quiscula). Nest predation was extremely low (∼2%), whereas more than 44% of 427 nests found during nest building never received an egg; this indicates that nest abandonment accounted for most nests without eggs. Nest construction was completed for 32% of nests that were abandoned. Few nests known to have received eggs were abandoned. As the breeding season progressed, both nest abandonment and time from nest completion to first egg decreased. It has been proposed that the delay in egg laying early in the season allows females to optimize timing of egg laying. Nest abandonment may also serve this purpose, but seems an unnecessarily expensive mechanism. Alternatively, nest abandonment could be involved with mate switching. Understanding why nests are abandoned requires data on the associated ecological circumstances, in addition to accurate identification of instances of abandonment. The latter requires distinguishing abandonment from cryptic predation. Rates of nest abandonment can be estimated for populations by using rates of known nest predation during egg laying. For individual nests, however, distinguishing abandonment from cryptic predation requires detailed observation (e.g. video cameras), except in circumstances such as ours, where predation is extremely low.Nidos sin Huevos:?Abandono o Depredación Críptica?
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Taborsky, Barbara, Marcel Honza, Wolfgang Vogl, Yvonne Teuschl, and Michael Taborsky. "Habitat and space use of European cuckoo females during the egg laying period." Behaviour 141, no. 7 (2004): 881–98. http://dx.doi.org/10.1163/1568539042265671.
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AbstractIn brood parasites, knowledge of spacing behaviour, habitat use and territoriality may reveal cues about how parasites find and use their hosts. To study the use of space and habitat of European cuckoos, Cuculus canorus, we radio-tagged 16 females during four consecutive reproductive seasons. We hypothesized that during the laying period cuckoo females should (1) use habitats selectively, and (2) attempt to monopolize potential egg laying areas to reduce competition for host nests. Our data are consistent with the first hypothesis: the use of pond edges compared to forest and transitional habitats was significantly greater than expected from the habitat availability in the total area and within individual female home ranges. All 26 directly observed egg layings and 27 nest visits without laying occurred at pond edges in nests of Acrocephalus spp. Females spent significantly more time at pond edges on egglaying days than on non-laying days. The second hypothesis was not supported: female home ranges overlapped similarly in all three major habitat categories of the potential egg laying areas, and only little aggression was observed between females. We discuss whether female cuckoos may lack territorial behaviour because they are not able to defend egg laying areas economically or because defence is not necessary due to sufficient availability of suitable host nests.
5
Verboven, Nanette, Bruno J. Ens, and Sharon Dechesne. "Effect of Investigator Disturbance on Nest Attendance and Egg Predation in Eurasian Oystercatchers." Auk 118, no. 2 (April 1, 2001): 503–8. http://dx.doi.org/10.1093/auk/118.2.503.
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AbstractEurasian Oystercatchers (Haematopus ostralegus) breeding on the salt marsh of Schiermonnikoog (Dutch Wadden Sea) lose many eggs to predators, mainly Herring (Larus argentatus) and Mew gulls (L. canus). We estimated that the probability for an egg to survive from laying until hatching was 69%. Daily egg mortality was higher during the laying period than during the incubation period. When researchers were present in the study area, oystercatchers spent more time at greater distances from the nest. We investigated whether human disturbance resulted in more eggs being lost to predators. Two experimental areas were in turn visited at high and at low frequency. From a preliminary analysis, we estimated higher daily egg mortality rates when nests were checked three times per day instead of once every other day. However, high-frequency nest checks provided more information on newly laid and lost eggs, especially during the laying period. After correcting for that extra information (by simply deleting it), the egg mortality rates were no longer different. We conclude that human disturbance did not increase egg loss, rather egg mortality rates were underestimated when nests were checked only once per two days.
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Fast, Peter L. F., H. Grant Gilchrist, and Robert G. Clark. "Nest-site materials affect nest-bowl use by Common Eiders (Somateria mollissima)." Canadian Journal of Zoology 88, no. 2 (February 2010): 214–18. http://dx.doi.org/10.1139/z09-131.
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Nest-site characteristics influence reproductive success in birds. Most studies of nest-site selection evaluate nest characteristics following the commencement of egg-laying, possibly overlooking the importance of pre-existing nest-site features that may be altered during the nesting process. Because Common Eiders ( Somateria mollissima (L.,1758)) often lay their eggs in nest bowls created in previous years, we were able to experimentally place moss or feather down in nest bowls prior to nesting. We then quantified whether these materials increased nest establishment or advanced laying dates relative to control nests and nests where material was removed prior to arrival of nesting females. We found no difference in the likelihood of successful nest establishment between groups. However, the onset of incubation occurred 2–3 days earlier in nest bowls that contained feather down versus nest bowls with little or no nesting material. Nest bowls containing feathers or vegetation may be selected first if they increase nest survival, perhaps by enhancing egg concealment during the critical early-laying period. The presence of material for egg concealment may be particularly important in nesting environments where tall or dense vegetation is not available to provide nest cover.
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DECARO JÚNIOR, SERGIO T., NILZA M. MARTINELLI, DOUGLAS H. B. MACCAGNAN, and EDUARDO S. D. B. P. RIBEIRO. "Oviposition of Quesada gigas (Hemiptera: Cicadidae) in coffee plants." Revista Colombiana de Entomología 38, no. 1 (June 30, 2012): 1–5. http://dx.doi.org/10.25100/socolen.v38i1.8906.
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Branches of coffee-plant were collected in São Sebastião do Paraíso County, Minas Gerais State, at the Experimental Station of the Agricultural Research Company (Empresa de Pesquisa Agropecuária de Minas Gerais - EP- AMIG), with the aim of studying various aspects of oviposition by Quesada gigas (Hemiptera: Cicadidae). The number of branches with Q. gigas egg nests was analyzed, as well as the number of nests per branch, the eggs per nest and the diameter of the egg nest location on the branch. The preference for oviposition either on alive or dry branches and the size of the egg were assessed. Egg-laying occurred only on dry branches. The mean of the branch diameter on which the egg nests occurred was 2.5 ± 0.53 mm. The number of eggs per nest averaged 13.2 ± 4.9, and the number of egg nests per branch was 2.2 ± 1.74. The eggs were 1.9 ± 0.08 mm long by 0.5 ± 0.04 mm wide. The largest diameters of the branches containing egg nests were found on the upper third of the trees, as well as the greatest amount of branches with egg nests, of egg nests per branch and of eggs per nest. The correlation relationship between all of the experiment variables was positive.
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Li, Zhong-qiu, Rong-rong Wang, Xue-lei Jiang, and Zhi-yuan Zhang. "New record of intraspecific nest parasitism by the Silky Starling (Sturnus sericeus)." F1000Research 1 (December 28, 2012): 71. http://dx.doi.org/10.12688/f1000research.1-71.v1.
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The Silky Starling (Sturnus sericeus) is endemic to East Asia and little is know about its’ breeding ecology. We found intraspecific nest parasitism (INP) by this species in a reproductive study conducted from March to June 2011. We found three nests were parasitized using the obvious morphological differences or partition of egg-laying. One egg appeared 3 days after the 26th female had finished laying eggs. One egg was different in color from the other five eggs in the 27th nest. The third instance was discovered in the 37th nest after the fledglings had fledged. Our findings confirmed INP by the Silky Starling.
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Walsh, John J., Ty A. Tuff, Alexander Cruz, and Jameson F. Chace. "Differential Parasitism Between Two Suitable Cowbird Hosts." Open Ornithology Journal 8, no. 1 (July 31, 2015): 32–38. http://dx.doi.org/10.2174/1874453201508010032.
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Host choice by the brood parasitic Brown-headed Cowbird (Molothrus ater) is an evolved response to host suitability, resulting in patterns of differential parasitism rates among species within a community. In the ponderosa pine (Pinus ponderosa) forests of the Colorado Front Range, we recorded that Western Wood-pewee (Contopus sordidulus) is infrequently parasitized (1%, n = 259 nests) by the Brown-headed Cowbird, whereas the Plumbeous Vireo (Vireo plumbeus) is heavily parasitized (51%, n = 292). To account for differences in parasitism rates on these species we experimentally parasitized pewee nests with cowbird eggs, and we compared host aggression towards cowbird models, host nest attentiveness, nest placement, and egg-laying dates in these species. Pewees accepted cowbirds eggs and reacted more aggressively towards the cowbird model than the control model, were more attentive at their nest sites than vireos, and placed their nests higher and closer to the trunk than vireos. Egg-laying dates for vireos and cowbirds overlapped more than the egg-laying dates for pewees and cowbirds. We suggest that temporal asynchrony in host availability, coupled with differences in nest placement and behavior at the nest, help to account for the observed differences in parasitism rates between these two species.
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Hartman, C. Alex, Joshua T. Ackerman, Sarah H. Peterson, Brady Fettig, Mike Casazza, and Mark P. Herzog. "Nest attendance, incubation constancy, and onset of incubation in dabbling ducks." PLOS ONE 18, no. 5 (May 19, 2023): e0286151. http://dx.doi.org/10.1371/journal.pone.0286151.
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In birds, parents must provide their eggs with a safe thermal environment suitable for embryonic development. Species with uniparental incubation must balance time spent incubating eggs with time spent away from the nest to satisfy self-maintenance needs. Patterns of nest attendance, therefore, influence embryonic development and the time it takes for eggs to hatch. We studied nest attendance (time on the nest), incubation constancy (time nests were at incubation temperatures), and variation in nest temperature of 1,414 dabbling duck nests of three species in northern California. Daily nest attendance increased from only 1–3% on the day the first egg was laid to 51–57% on the day of clutch completion, and 80–83% after clutch completion through hatch. Variation in nest temperature also decreased gradually during egg-laying, and then dropped sharply (33–38%) between the day of and the day after clutch completion because increased nest attendance, particularly at night, resulted in more consistent nest temperatures. During the egg-laying stage, nocturnal nest attendance was low (13–25%), whereas after clutch completion, nest attendance was greater at night (≥87%) than during the day (70–77%) because most incubation recesses occurred during the day. Moreover, during egg-laying, nest attendance and incubation constancy increased more slowly among nests with larger final clutch sizes, suggesting that the number of eggs remaining to be laid is a major driver of incubation effort during egg-laying. Although overall nest attendance after clutch completion was similar among species, the average length of individual incubation bouts was greatest among gadwall (Mareca strepera; 779 minutes), followed by mallard (Anas platyrhynchos; 636 minutes) and then cinnamon teal (Spatula cyanoptera; 347 minutes). These results demonstrate that dabbling ducks moderate their incubation behavior according to nest stage, nest age, time of day, and clutch size and this moderation likely has important implications for egg development and overall nest success.
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Pilyukshina, Elena, Vladimir Khaustov, Alexander Ozhimkov, Valentina Rusanova, and Alexey Popelyaev. "Reproductive qualities of meat chickens of the parent flock when using automatic nests." E3S Web of Conferences 222 (2020): 03007. http://dx.doi.org/10.1051/e3sconf/202022203007.
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The aim of the study presented in this paper was to compare the reproductive qualities of laying hens of the parent flock of the ROSS 308 cross when using manual and automatic egg collection. The experimental part was carried out in the production conditions of a separate subdivision “Novosafonovskaya poultry farm” of Kuzbass Broiler LLC on laying hens of the parent flock of the ROSS 308 cross at the age of 155-435 days. The use of automatic nests for collecting hatching eggs did not affect the intensity of egg production, but contributed to an increase in the yield of hatching eggs due to a decrease in the culled eggs because of egg contamination, breakage, cracked shell and others. A decrease in the number of cleaned eggs among the hatching eggs contributed to an increase in the hatching of chicks and, as a consequence, an increase in the yield of day old chicks per initial layer by 11.9 heads or 8.5%.
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Poole, Alan. "Courtship Feeding and Osprey Reproduction." Auk 102, no. 3 (July 1, 1985): 479–92. http://dx.doi.org/10.1093/auk/102.3.479.
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Abstract A female Osprey (Pandion haliaetus) usually is fed exclusively by its mate between pair formation and egg-laying. Laying dates and courtship periods-but not clutch size, egg size, breeding success, or female weight reserves-were correlated (negatively) with the prelaying feeding rates of 12 females breeding in a coastal Massachusetts colony. However, the age of a pair and of its bond influenced laying dates and courtship periods more than food intake. Older and more experienced pairs arrived earlier and laid eggs more quickly than younger pairs. As an independent test of food limitation in Ospreys producing eggs, supplemental food was provided to 4 nests during courtship. Supplemental food did not influence a female's reproductive output or timing, but males at nests receiving extra food showed reduced rates of foraging. Egg production boosted the daily energy expenditure of female Ospreys by only about 20% and females gained little weight during courtship, suggesting that egg-laying is not a demanding process in this species. Because age and mate retention had a greater effect on the reproductive output and timing of female Ospreys than rates of food consumption during courtship, and because there was evidence that poorly fed females were less willing to copulate and less faithful to their mates than well-fed females, it is argued that Osprey courtship feeding may function primarily to ensure mate fidelity.
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Honza, Marcel, Michal Šulc, Václav Jelínek, Milica Požgayová, and Petr Procházka. "Brood parasites lay eggs matching the appearance of host clutches." Proceedings of the Royal Society B: Biological Sciences 281, no. 1774 (January 7, 2014): 20132665. http://dx.doi.org/10.1098/rspb.2013.2665.
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Interspecific brood parasitism represents a prime example of the coevolutionary arms race where each party has evolved strategies in response to the other. Here, we investigated whether common cuckoos ( Cuculus canorus ) actively select nests within a host population to match the egg appearance of a particular host clutch. To achieve this goal, we quantified the degree of egg matching using the avian vision modelling approach. Randomization tests revealed that cuckoo eggs in naturally parasitized nests showed lower chromatic contrast to host eggs than those assigned randomly to other nests with egg-laying date similar to naturally parasitized clutches. Moreover, egg matching in terms of chromaticity was better in naturally parasitized nests than it would be in the nests of the nearest active non-parasitized neighbour. However, there was no indication of matching in achromatic spectral characteristics whatsoever. Thus, our results clearly indicate that cuckoos select certain host nests to increase matching of their own eggs with host clutches, but only in chromatic characteristics. Our results suggest that the ability of cuckoos to actively choose host nests based on the eggshell appearance imposes a strong selection pressure on host egg recognition.
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Aitouakli, Thilelli, and Ettayib Bensaci. "Breeding Ecology and Nest- Site Selection of Turtle Doves (Streptopelia turtur) in Three New Orchard Habitats." Journal of Bioresource Management 8, no. 2 (April 23, 2021): 01–13. http://dx.doi.org/10.35691/jbm.1202.0175.
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The main aim of our work was to investigate the breeding parameters in three orchard types in Algeria (apple, cherry and nectarine) for better conservation of existing species. A total of 149 active Turtle dove nests were monitored in these man–made agro-systems. Egg laying occurred from early May and continued until mid-August. Egg laying started later in cherry trees and stopped earlier in nectarines. Nest density was higher in apple orchards. Nests were located higher in nectarine. Clutch size was similar among orchard types. Northeast was the dominant orientation in all orchards. Breeding success was higher than that recorded in former studies. Desertion was the main cause of nest failure. The apple orchards are the preferred breeding area for turtle dove in this region.
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Forbes, Mark R. L., and C. Davison Ankney. "Nest attendance by adult Pied-billed Grebes, Podilymbus podiceps (L.)." Canadian Journal of Zoology 66, no. 9 (September 1, 1988): 2019–23. http://dx.doi.org/10.1139/z88-296.
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In 1984, we monitored diurnal attendance by adult Pied-billed Grebes, Podilymbus podiceps (L.), on nests found in the emergent vegetation of ponds located near Minnedosa, Manitoba (55°16′N, 99°50′W). Adults increased attendance on nests over the egg-laying period; by the time four of six to eight eggs had been laid, adults spent roughly 90% of daylight time on nests. Nest attendance remained high during the post-laying period, but declined to between 75 and 85% of monitoring time later in the hataching period. Time of day did not affect the amount of time spent by adults off the nest. Previous visits by observers to nests on a given day, however, had a profound effect in that adults spent less time on "disturbed" than on "undisturbed" nests during the laying period, but more time on disturbed nests during the hatching period. Females accounted for roughly 70% of the total time spent by adults on nests during the hatching period, but were equal to males in this regard during the laying and post-laying stages. Our data suggest that nest attendance by both sexes before clutch completion largely determines onset of incubation and consequently the hatching interval for Pied-billed Grebe broods. Neglect of eggs by adults after the onset of hatching, however, may exaggerate hatching intervals.
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Belabed, Bourhane-Eddine, Mohammed Athamnia, Laïd Touati, Farrah Samraoui, Abdennour Boucheker, and Boudjéma Samraoui. "The early bird catches the worm: age-specific arrival time influences reproductive performance in the White Stork Ciconia ciconia." Bird Study 66, no. 1 (January 2, 2019): 121–29. http://dx.doi.org/10.1080/00063657.2019.1618240.
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<sec><title>Capsule</title>Age, arrival date and egg laying date are essentially closely related and determine reproductive performance in the White Stork Ciconia ciconia.</sec><sec><title>Aims</title>To describe the impact of age, arrival date and egg laying date on breeding success in the White Stork.</sec><sec><title>Methods</title>Ringing data from a White Stork breeding colony of 212 nests at Dréan, Algeria, were used to model the relationship between age, arrival date, laying date and reproductive performance. Seventy breeders that were individually colour-ringed as nestlings were monitored.</sec><sec><title>Results</title>Birds breeding on the periphery of the colony had significantly smaller nests and showed a tendency towards later laying dates, but they did not differ from centrally nesting birds in age or arrival date. First year birds did not breed and second year birds were significantly more likely than older age groups to occupy nests but fail to lay eggs. Older birds arrived earlier at the breeding colony and had a higher probability of initiating laying than younger birds. They also had a higher probability of nesting successfully and fledging a larger number of young.</sec><sec><title>Conclusion</title>Age determined arrival and laying dates and influenced breeding performance in the White Stork.</sec>
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Arheimer, Ola, and Sören Svensson. "Breeding performance of the Fieldfare Turdus pilaris in the subalpine birch zone in southern Lapland: a 20 year study." Ornis Svecica 18, no. 1 (January 1, 2008): 17–44. http://dx.doi.org/10.34080/os.v18.22679.
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A Fieldfare population, on average c. 160 pairs, was studied in subalpine birch forest in southern Lapland (c. 66°N; 500–600 m.a.s.l.) in 1983–2002. Onset of egg-laying showed no temporal trend, consistent with absence of spring temperature trend. Eggs were laid with an interval of c. 21 hours and 45 minutes, not 24 hours as normal in passerines. This reduces the exposure time to depredation during egg-laying with 9%. Egg hatchability was 96%. Egg parasitism never occurred. Depredation of nests was 46%, but very variable. Replacement and second clutches did not occur. Although an average of 4.45 young fledged from successful nests (≥1 fledgling), only 2.11 fledglings were produced per pair and year. The population varied without trend over the study period. Adult survival, estimated by the proportion of adults at the start of breeding, was 58%. This infers that first year survival must be at least c. 40%. Since this is a likely value, it seems that the Fieldfare population of the subalpine birch forest is selfsustained and not dependent upon immigration.
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Touarfia, Moundji, and Nadhra Boukrouma. "Breeding ecology of the northern shoveller (Spatula clypeata) in Tiffech Lake (Souk Ahras, Northeastern Algeria)." Acta Musei Silesiae, Scientiae Naturales 71, no. 2 (May 1, 2022): 97–104. http://dx.doi.org/10.2478/cszma-2022-0005.
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Abstract The breeding behavior of Northern Shoveler (Spatula clypeata) was studied from January 2019 to March 2021 in Tiffech lake, an artificial wetland, in Souk Ahras Province, Northeastern Algeria. On this ecosystem, egg-laying occurred from earlier January to mid-March. In this study, there was a positive correlation between the egg-laying period and the number of active nests. The mean incubation period was 36.0 days. Clutches started later in the season and had a shorter incubation duration than early clutches. Hatching success amounted to 79.2% (n= 52 nests) and hatching success from eggs 37.6. In this study we measured water depth to control differences in habitats availability for the species, we speculate that differences in food abundance, water depth, and behavioral strategies during the breeding season collectively influence the selection of breeding habitat.
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Arnold, Todd W., David W. Howerter, James H. Devries, Brian L. Joynt, Robert B. Emery, and Michael G. Anderson. "Continuous Laying and Clutch-Size Limitation in Mallards." Auk 119, no. 1 (January 1, 2002): 261–66. http://dx.doi.org/10.1093/auk/119.1.261.
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Abstract We assessed nutritional constraints on clutch size in Mallards (Anas platyrhynchos) by observing incidence and consequences of continuous laying—the sequential production of eggs in two or more nest bowls. Continuous laying behavior was detected in 278 of 3,064 radiotracked Mallards (9.1%). Continuous laying females produced an average of 12.12 total eggs (SD = 2.70, range 5–18, n = 69), versus 8.90 eggs for normal nesting females (SD = 1.67, range 4–14, n = 587). On average, continuous laying females were 25 g heavier than noncontinuous laying females, and body mass was positively correlated with egg production among continuous laying females. Nest success was not affected by continuous laying, but continuous laying females that abandoned their nests were more likely to be young or to have laid a greater number of eggs. A large component of the breeding Mallard population can lay more eggs than they typically do, and there appear to be minimal consequences of that behavior. These observations appear inconsistent with the egg-formation hypothesis.
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Oliveira Filho, Júlio César de, Hugo Cardoso de Moura Costa, and Úrsula Márcia Lobo Braga. "Egg-laying and foam-beating in Leptodactylus fuscus (Anura, Leptodactylidae)." Biota Neotropica 5, no. 2 (2005): 319–20. http://dx.doi.org/10.1590/s1676-06032005000300022.
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Species of the Leptodactylus fuscus group lay their eggs in foam nests in underground chambers the males excavate. However, little is known about the interactions between males and females while egg-laying. We recorded egg-laying behavior in Leptodactylus fuscus. Observations were possible because the chambers walls were partially damaged (small holes). Within the chamber, the male holds the female in an axillary amplexus. In a typical sequence of egg-releasing/foam-beating, the male makes alternate movements of legs in a series of kicks. After a bout of foam-beating the male releases the female removing his arms from her axils. When freed by the male, the female turned a little for a new bout of beating, being seized in an axillary amplexus again. In the species of Leptodactylus of the fuscus group the lack of thumb asperities and spines may be related to their terrestrial egg-laying behavior and to the stability the couples have within the chamber.
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Enemar, Anders. "Incubation, hatching, and clutch desertion of the Treecreeper Certhia familiaris in south-western Sweden." Ornis Svecica 5, no. 3–4 (October 1, 1995): 111–24. http://dx.doi.org/10.34080/os.v5.23000.
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Breeding data were collected on a Treecreeper population nesting in artificial nest sites, erected in deciduous forests in south-western Sweden. From 1982 through 1994, 74 incubation periods were estimated by measuring the time from laying of the last egg to either the hatching of that egg or the appearance of the last hatchling. The mean period was 15.7±1.44 (SD) days, showing a negative relation to laying date from about 17 days for clutches laid in early April to about 14 days in late June, as well as to the mean ambient temperature of the egg-laying period and the first five days of incubation. Mean hatching asynchrony was 1.0±0.37 days (n=38). Approximately 90% of the eggs surviving until hatching produced viable chicks. A third of the losses were perished hatchlings, the rest unhatched egg . Out of 443 clutches with at least one egg, 13% were abandoned without signs of robbing or other destruction. Part of the desertions occurred in connection with heavy rain soaking the nests. —The concept of incubation period is discussed.
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Farkas, Tamás Péter, Sándor Szász, Attila Orbán, Dávid Mezőszentgyörgyi, Lilla Pető, and Zoltán Sütő. "Examination of Nesting Behavior of Laying Hens of Different Genotypes Housed in Indoor Alternative Pens Using a Video System." Applied Sciences 12, no. 18 (September 9, 2022): 9093. http://dx.doi.org/10.3390/app12189093.
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The aim of the research was to examine how the nest selection preference of laying hens with different genotypes differed, the proportion of eggs laid in the litter, eggs laid in the upper and bottom nests, and the number and duration of nest visits. The experiment was conducted with laying hen genotypes provided by Bábolna TETRA Ltd. (Babolna, Hungary) (Commercial hybrid (C); pure-line maternal (Maternal); pure-line paternal offspring group (Paternal)). N = 318; n = 106 hen/genotype; and 53 hens/pen. We placed 53 19-week-old, non-beak-trimmed hens in each of the six 5.52 m2 alternative pens. We provided 14 nests for the hens at two levels per pen (3.8 hens/nest). We recorded the number of eggs laid in the nests on the bottom and upper levels, as well as within the litter. Infrared cameras were installed above the pens, and we conducted recordings on a test day at the beginning of the third production month. In our results, we found a significant difference in the proportion of litter eggs overall during the 12 months of production (C. hybrid: 30.7%; Paternal: 41.1%; Maternal: 10.2%). A significant difference was found between all genotypes in the proportions of eggs laid at the bottom (B) and upper (U) level during the 12 months of production (C. hybrid: B: 72.2%, U: 27.8%; Paternal: B: 88.0%, U: 12.0%; Maternal: B: 71.4%, U: 28.6%). The evaluation of the video recordings revealed that the C. hybrid and Paternal genotypes visited the bottom nests in 97.2% and 96.0% of the cases, respectively, and the Maternal genotype individuals in a significantly lower proportion, 72.5% of the cases; the Paternal genotype spent significantly more time (13.4 min) on average in the bottom nests compared with the C. hybrid (7.9 min) and the Maternal genotypes (8.6 min). Our conclusion is that it is not enough to ensure the desired ratio of egg nests in egg production, as laying hens may not use nests in certain positions at all. This generates a relative shortage of egg nests and can increase the ratio of eggs laid in the litter, which in turn involves human health risks.
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Morris, Ralph D., and John W. Chardine. "The effects of ice cover over the colony site on reproductive activities of herring gulls." Canadian Journal of Zoology 63, no. 3 (March 1, 1985): 607–11. http://dx.doi.org/10.1139/z85-088.
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The substrate at a herring gull (Larus argentatus) colony on Lake Erie near Port Colborne, Ontario (Lighthouse), was completely covered by a thick layer of ice throughout April and early May 1982. Egg laying normally begins at this location in mid-April. An adjacent herring gull colony (Canada Furnace) was ice free. Herring gull pairs at the Lighthouse colony defended territories on top of the ice but only 3 of about 90 pairs built nests on the ice. Birds neither deserted the colony nor moved within it to ice-free areas as these became available. The mean date of egg laying at the Lighthouse colony in 1982 was about 2 weeks later than in the previous year. At the adjacent Canada Furnace colony, there was no difference in the mean date of egg laying between the 2 years. There were no differences in the distribution of clutch sizes, mean clutch sizes, or hatching success of three-egg clutches laid within ± 1 SD of the mean date of egg laying at either colony in the 2 years. By these measures, the ice-induced delay in breeding chronology of birds at the Lighthouse colony in 1982 did not adversely effect reproductive performance in that year.
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Soler, Manuel, Tomás Pérez-Contreras, and Juan José Soler. "Great spotted cuckoos show dynamic patterns of host selection during the breeding season. The importance of laying stage and parasitism status of magpie nests." Behavioral Ecology 31, no. 2 (December 28, 2019): 467–74. http://dx.doi.org/10.1093/beheco/arz208.
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Abstract Avian brood parasites depend entirely on their hosts to raise their nestlings until independence. Thus, parasite females should select suitable host nests for egg laying according to traits that enhance offspring survival. The availability of nests of certain characteristics influencing the survival of parasitic offspring is, however, temporally dynamic and, thus, patterns of host selection should be evaluated considering characteristics of available host nests the day of parasitism. This allows detecting possible seasonal changes and, therefore, a more realistic picture of host selection by brood parasites. In this paper, we adopt such a new approach and consider daily availability of magpie (Pica pica) host nests at different breeding stage that were or were not parasitized by the great spotted cuckoo (Clamator glandarius). Theory predicts that cuckoos should select host nests at the laying stage. Accordingly, we detected that cuckoos preferred to parasitize magpie nests at the laying stage but, mainly, those that already harbored one or two cuckoo eggs, which may seem counterintuitive. We also showed that patterns of host selection by cuckoos varied during the breeding season, which implies that brood parasite–host interaction is dynamic depending on phenology. These patterns are hidden when not considering the temporally dynamic nature of the availability of host nests of characteristics of interest. We discuss the importance of such patterns and considering diary hosts nests availability for detecting them.
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Whittingham, Linda A., and Peter O. Dunn. "Female Responses to Intraspecific Brood Parasitism in the Tree Swallow." Condor 103, no. 1 (February 1, 2001): 166–70. http://dx.doi.org/10.1093/condor/103.1.166.
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Abstract We studied female responses to experimental intraspecific brood parasitism (IBP), or egg-dumping, in Tree Swallows (Tachycineta bicolor). Unlike other species of swallows, Tree Swallow nests are rarely parasitized by conspecifics. We experimentally parasitized nests of Tree Swallows to investigate how females respond to uncertain maternity. Host females accepted a parasitic egg if it was added to the nest within 3 days of the host's first egg (62%). In contrast, the host female buried the parasitic egg (24%) or deserted the nest (14%) when the parasitic egg was added 4 or more days before the host's first egg. The acceptance of parasitic eggs close to the host's own laying date is similar to the behavior reported for other species; however, egg burial and nest desertion appear to be rare as responses to intraspecific brood parasitism. We suggest that the low level of IBP in Tree Swallows has evolved as an indirect consequence of females defending their nest cavity against usurpation.
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Macedo, Regina H. F., Mariana Cariello, and Laura Muniz. "Context and Frequency of Infanticide in Communally Breeding Guira Cuckoos." Condor 103, no. 1 (February 1, 2001): 170–75. http://dx.doi.org/10.1093/condor/103.1.170.
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Abstract We studied the context of brood reduction through infanticide by communally breeding Guira Cuckoos (Guira guira) in central Brazil. During seven reproductive seasons, we monitored 142 nests from egg laying until fledging. Almost all nests (97%) lost eggs through ejection, and chick deaths occurred in 72% of all nests with hatchlings. There was evidence for infanticide in 38% of the nests that exhibited some mortality. We compared egg and chick mortality in the early part of the season with the later part, when insect abundance declines, but found no significant differences. Less than one-third of all nests monitored showed asynchronous hatching of eggs, and in those that did, chick death was not in reverse hatch order. Although there are several plausible explanations for infanticide, we highlight one likely candidate, which is its interpretation as a sexually selected trait where individuals gain reproductive benefits by provoking the group's nesting failure.
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Pöysä, Hannu. "Low host recognition tendency revealed by experimentally induced parasitic egg laying in the common goldeneye (Bucephala clangula)." Canadian Journal of Zoology 81, no. 9 (September 1, 2003): 1561–65. http://dx.doi.org/10.1139/z03-147.
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Host-parasite relatedness has been suggested to promote the evolution of conspecific brood parasitism, an alternative reproductive tactic pursued by females in several animal taxa. An essential prerequisite for relatedness to promote brood parasitism is accurate kin recognition, including the recognition of related hosts by parasites. I performed a field experiment to address the accuracy of host recognition by parasites in the common goldeneye (Bucephala clangula), a cavity-nesting duck. I studied whether parasites discriminate between experimental nests that did not have a host (i.e., new nest boxes that contained chicken eggs dyed to mimic the colour of common goldeneye eggs) and real nests that did have a host (i.e., active nests that progressed to incubation). Parasitic egg laying in the experimental nests was not constrained by the lack of contemporarily available nests that had a host; it was also not constrained by the lack of suitable and empty nest sites. There was no difference in the start of parasitic laying between the experimental and real nests. The experimental nests and real nests were equally parasitized. The findings suggest that host recognition by parasites is not sophisticated in the common goldeneye, questioning the possible function of accurate kin recognition in brood parasitism in this species.
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Sealy, Spencer G., and Diane L. Neudorf. "Reactions of Four Passerine Species To Threats of Predation and Cowbird Parasitism: Enemy Recognition or Generalized Responses?" Behaviour 123, no. 1-2 (1992): 84–105. http://dx.doi.org/10.1163/156853992x00138.
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AbstractFour host species of the parasitic brown-headed cowbird (Molothrus ater) were exposed to taxidermic mounts of a female cowbird, fox sparrow (Passerella iliaca), and common grackle (Quiscalus quiscula) at their nests during their egg-laying or nestling stage. Red-winged blackbirds (Agelaius phoeniceus), a species that accepts cowbird eggs laid in their nests, responded more aggressively to cowbird models early in their nesting cycle, indicating that they recognized the unique threat the cowbird posed. Gray catbirds (Dumetella carolinensis), northern orioles (Icterus galbula), and cedar waxwings (Bombycilla cedrorum) can remove cowbird eggs from their nests and for the most part they responded similarly to cowbird models and the "nonthreatening control," i.e. a fox sparrow. Cedar waxwings were nonaggressive to all the models and may rely on concealment to protect their nests from enemies. Removal of cowbird eggs by puncture ejection is more risky than grasp ejection. Despite this, orioles and waxwings (puncture ejectors) were not significantly more aggressive to cowbird models at egg laying than catbirds (grasp ejectors). Responses of the three rejector species toward the cowbird model did not change over the nesting cycle, indicating further that they do not recognize cowbirds as a unique threat. Rejector species may not recognize cowbirds because they have little experience with them. With the exception of waxwings, all of the hosts recognized the grackle as an enemy and increased their levels of defence from the laying to nestling stages. Three of the host-species did not simply respond in a generalized manner to any intruder at their nests but indeed recognized specific enemies. Considerable interspecific variability exists amongst the four species in defensive behaviours, which may reflect their different nesting habitats.
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Riehl, Christina. "Living with strangers: direct benefits favour non-kin cooperation in a communally nesting bird." Proceedings of the Royal Society B: Biological Sciences 278, no. 1712 (November 10, 2010): 1728–35. http://dx.doi.org/10.1098/rspb.2010.1752.
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The greater ani ( Crotophaga major ), a Neotropical cuckoo, exhibits an unusual breeding system in which several socially monogamous pairs lay eggs in a single nest and contribute care to the communal clutch. Cooperative nesting is costly—females compete for reproduction by ejecting each other's eggs—but the potential direct or indirect fitness benefits that might accrue to group members have not been identified. In this study, I used molecular genotyping to quantify patterns of genetic relatedness and individual reproductive success within social groups in a single colour-banded population. Microsatellite analysis of 122 individuals in 49 groups revealed that group members are not genetic relatives. Group size was strongly correlated with individual reproductive success: solitary pairs were extremely rare and never successful, and nests attended by two pairs were significantly more likely to be depredated than were nests attended by three pairs. Egg loss, a consequence of reproductive competition, was greater in large groups and disproportionately affected females that initiated laying. However, early-laying females compensated for egg losses by laying larger clutches, and female group members switched positions in the laying order across nesting attempts. The greater ani, therefore, appears to be one of the few species in which cooperative breeding among unrelated individuals is favoured by direct, shared benefits that outweigh the substantial costs of reproductive competition.
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Gloag, Ros, Laurie-Anne Keller, and Naomi E. Langmore. "Cryptic cuckoo eggs hide from competing cuckoos." Proceedings of the Royal Society B: Biological Sciences 281, no. 1792 (October 7, 2014): 20141014. http://dx.doi.org/10.1098/rspb.2014.1014.
Full textAbstract:
Interspecific arms races between cuckoos and their hosts have produced remarkable examples of mimicry, with parasite eggs evolving to match host egg appearance and so evade removal by hosts. Certain bronze-cuckoo species, however, lay eggs that are cryptic rather than mimetic. These eggs are coated in a low luminance pigment that camouflages them within the dark interiors of hosts' nests. We investigated whether cuckoo egg crypsis is likely to have arisen from the same coevolutionary processes known to favour egg mimicry. We added high and low luminance-painted eggs to the nests of large-billed gerygones ( Gerygone magnirostris ), a host of the little bronze-cuckoo ( Chalcites minutillus ). Gerygones rarely rejected either egg type, and did not reject natural cuckoo eggs. Cuckoos, by contrast, regularly removed an egg from clutches before laying their own and were five times more likely to remove a high luminance model than its low luminance counterpart. Given that we found one-third of all parasitized nests were exploited by multiple cuckoos, our results suggest that competition between cuckoos has been the key selective agent for egg crypsis. In such intraspecific arms races, crypsis may be favoured over mimicry because it can reduce the risk of egg removal to levels below chance.
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Bancroft, G. Thomas. "Nesting Success and Mortality of the Boat-Tailed Grackle." Auk 103, no. 1 (January 1, 1986): 86–99. http://dx.doi.org/10.1093/auk/103.1.86.
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Abstract Of 605 Boat-tailed Grackle (Quiscalus major) nests with complete clutches, 60.5% fledged young. Survival of nests to the hatching stage averaged 78.7%, and survival from hatching to fledging averaged 76.9%. Nesting success between localities varied from none to almost all nests fledging some young. Fledging success for 3-egg clutches averaged 64.8% and was significantly higher than the 50.8% success rate that 2-egg clutches averaged. Individual survival of eggs from laying through hatching was lower in 2-egg clutches than in 3-egg clutches, but from hatching to fledging nestling survival was higher. Thus, in contrast to nest survival, equal proportions of eggs in 2- and 3-egg clutches produced fledglings. Predation was the greatest source of mortality, with predators taking 14.8% of the 1,605 eggs and 13.1% of the 1,145 nestlings. Of eggs that survived to the hatching stage, 9.2% failed to hatch. Starvation (13.4%) was the most common source of nestling mortality. Nest abandonment accounted for the death of 5.7% of the eggs and 2.9% of the young. The sources of mortality varied spatially and temporally in an unpredictable way. This uncertainty has resulted in the flexible nesting biology of grackles.
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Kayaalp, Pelin, and Michael P. Schwarz. "Egg size and number is influenced by both environmental and social factors in a facultatively social bee." Australian Journal of Zoology 55, no. 6 (2007): 357. http://dx.doi.org/10.1071/zo07022.
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Social factors influencing the trade-off between egg size and number have been almost entirely neglected in studies of social insects. We examined egg size and number in an Australian allodapine bee where nutritional resource availability and social competition during egg laying vary over colony development. We hypothesised that during August queens should lay many eggs to provide work incentives for subordinates, but because resources are strongly limited these eggs will be small. In spring, resources are less limited but some subordinates also lay eggs, resulting in competition between offspring for communally provided food. Here, we hypothesised that females should attempt to direct resources preferentially to their own offspring by laying large eggs. We analysed egg numbers and weights as functions of colony size. We found that a trade-off existed in August nests but that egg size increased with egg number in October. In November, when larval eclosion was commencing, colonies with larvae had smaller mean egg weights than those with only eggs, suggesting that resources are directed away from oviposition towards larval provisioning. Our analyses suggest that egg size is a function of egg number, rather than colony size per se.
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Tacoli, Federico, Elena Cargnus, Pietro Zandigiacomo, and Francesco Pavan. "Side Effects of Sulfur Dust on the European Grapevine Moth Lobesia botrana and the Predatory Mite Kampimodromus aberrans in Vineyards." Insects 11, no. 11 (November 23, 2020): 825. http://dx.doi.org/10.3390/insects11110825.
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To reduce the impact of synthetic insecticides on human health and the environment, eco-friendly alternatives must be investigated. Knowledge of the side effects on pests and natural enemies of natural products applied to vineyards is very useful. Sulfur dust, which is used in vineyards to control powdery mildew, is investigated in laboratory and field bioassays for its effects on Lobesia botrana egg laying, egg hatching, and larval settlement. In field trials, the efficacy of sulfur dust against the two L. botrana carpophagous generations is compared with that of Bacillus thuringiensis and kaolin, and its side effects on the phytoseiid mite Kampimodromus aberrans are evaluated. In the bioassays, sulfur dust reduced female survival by 43%, egg laying by around 80%, egg hatching by 10%, and larval settlement by 55%. In field trials, sulfur dust caused a significant decrease in the number of L. botrana larval nests of both generations, even though the efficacy was lower than that of B. thuringiensis. No negative effects of sulfur dust on the predatory mite population density was observed. On the basis of these results, in the context of Integrated Pest Management strategies in vineyards, the activity of sulfur dust against L. botrana could be exploited by timing its application to the beginning of egg laying.
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White, David J., Lucy Ho, and Grace Freed-Brown. "Counting Chicks Before They Hatch." Psychological Science 20, no. 9 (September 2009): 1140–45. http://dx.doi.org/10.1111/j.1467-9280.2009.02418.x.
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Here we show that demands associated with brood parasitism have favored sophisticated cognitive abilities in female brown-headed cowbirds. We discovered that cowbirds can use the rate at which eggs are added to a nest across days to assess the readiness of the nest for incubation, which would allow them to synchronize laying with the host and avoid nests where incubation has most likely commenced. In three experiments, cowbirds investigated and laid eggs in artificial nests that differed in the number of eggs they contained. Across days, we added eggs to nests at different rates to simulate differences in the timing of reproduction of the hosts. Cowbirds avoided a nest if the number of eggs that had been added was less than the number of days that had elapsed. The ability of females to remember egg number and compare changes in egg number across days allows them to select nests most suitable for parasitism.
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Tacchi, Maria Fernanda, Fernanda Peres Quirino, Diego Júnior Martins Ferreira, Lílian Gomes Afonso, Federico Tognin, and Daniel Negreiros. "Effect of sand granulometry on the egg hatchling success of the sea turtle Caretta caretta." Neotropical Biology and Conservation 14, no. 1 (April 11, 2019): 43–54. http://dx.doi.org/10.3897/neotropical.14.e34836.
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The environmental characteristics of nesting sites of sea turtles may directly interfere with the egg hatchling success. The objective of the present study was to evaluate the factors that affect the success of hatchling in the nests of the loggerhead sea turtle (Caretta caretta). Data from 37 nests of C. caretta from the coast of Mata de São João, Bahia, northeastern Brazil, were obtained from TAMAR, Sauípe station. Samples of sand were collected in each nest to determine the granulometry. A significant negative relationship was found between the stillborn rate and the fine sand ratio (r2 = 0.119; p = 0.036), indicating that a larger fraction of fine sand had a positive effect on nest hatchling success. The egg laying date also had a significant influence on the rate of stillbirths (r2 = 0.163; p = 0.013), with a trend towards a higher stillbirth rate, the later the laying date of the eggs. There is indication that the transfer of eggs to sites with more favorable characteristics may be considered as a potential alternative to increase the hatchling success rate of C. caretta eggs.
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Enos, Janice K., Mark E. Hauber, and Zachary Aidala. "Delayed timing of breeding attempts, but not time lost to nest construction, reduces the annual reproductive output of the Eastern Phoebe (Sayornis phoebe)." Avian Biology Research 15, no. 1 (December 29, 2021): 34–40. http://dx.doi.org/10.1177/17581559211066094.
Full textAbstract:
For many birds, nest construction is a costly aspect of parental care, trading finite energetic resources between parental care and self-maintenance. For multi-brooded organisms with short breeding seasons, such as migratory passerines, repeated nest construction could be especially costly if the activity delays the onset of breeding attempts. Earlier studies on passerines that reuse nests between breeding seasons suggested that time lost to initial nest construction reduces seasonal reproductive output. However, costs associated with building new nests between breeding attempts, within the same breeding season, have largely been ignored. Here, we experimentally removed first nests, after fledging or failing, of Eastern Phoebes ( Sayornis phoebe), to evaluate how the annual onset of breeding and nest construction between breeding attempts affected parental investment into second attempts. We found that first egg laying date negatively predicted the probability of second breeding attempts, but experimental treatment (first nest removal vs. control) did not. Neither first egg laying date nor treatment statistically influenced any of the reproductive traits in second breeding attempts (clutch size, nestling body condition, and nestling growth rate). We conclude that in this species, second breeding attempts are limited by the initial onset of seasonal reproduction, and not by time lost to nest construction between breeding attempts.
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Mougin, Jean-Louis. "“Two-egg clutches” in Cory’s Shearwater (Calonectris diomedea)." El Hornero 16, no. 2 (December 1, 2001): 65–70. http://dx.doi.org/10.56178/eh.v16i2.896.
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In the Cory's Shearwater (Calonectris diomedea) of Selvagem Grande, “two-egg clutches” represented 0.52% of the total number of clutches. “Two-egg clutches” were found principally in attractive nests occupied by inexperienced breeders. The first egg seemed to be laid mostly by lonely females taking advantage of the pre-laying exodus to enter the temporarily empty nest of a young inexperienced pair. These females deserted their egg after a few days; then the legitimate tenants layed the second egg. The first egg was deserted on average after three days and replaced four days later. The breeding success of “two-egg clutches” was significantly lower than that of one-egg clutches, because of the failure of the first egg. Among other Procellariiformes, as in Cory's Shearwaters, “two-egg clutches” are always rare and show little success.
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González-Desales, Giovany A., Octavio Monroy-Vilchis, Martha M. Zarco-González, and Pierre Charruau. "Nesting ecology of the American crocodile in La Encrucijada Biosphere Reserve, Mexico." Amphibia-Reptilia 37, no. 3 (2016): 261–71. http://dx.doi.org/10.1163/15685381-00003051.
Full textAbstract:
Nesting of the American crocodile (Crocodylus acutus) is affected by natural and anthropogenic processes. In Mexico, few studies exist on reproductive traits of wild populations. We assessed the key reproductive characteristics ofC. acutusin the La Encrucijada biosphere reserve and the environmental and anthropogenic factors that influence them. From February to June 2014, we searched for nests in the reserve. Clutch incubation temperature was recorded by data loggers and climatic variables were obtained from La Encrucijada meteorological station. Additionally, outside the study area, net primary productivity was obtained for different sites in Mexico to relate it to clutch characteristics. We found 34 nests in nine nesting areas. Egg laying occurred in March, and hatching took place from mid-May to early June. Mean clutch and eggs characteristics are among the higher reported forC. acutus. Some egg attributes had a relationship with the net primary productivity. There was no relation between hatching success and external and internal characteristics of the nest. A high percentage of nests was poached (50%) mainly for egg consumption and fear of crocodiles, and the nests closer to the river, trees or human settlements are more likely to be poached.
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Conrad, Kelvin F., and Raleigh J. Robertson. "Clutch size in eastern phoebes (Sayornis phoebe). I. The cost of nest building." Canadian Journal of Zoology 71, no. 5 (May 1, 1993): 1003–7. http://dx.doi.org/10.1139/z93-133.
Full textAbstract:
Eastern phoebes (Sayornis phoebe) may build new nests or repair previously built ones. New nests may be of two types: statant (built on supporting ledges) or adherent (plastered to a vertical surface). Repaired nests are statant. Previous workers compared phoebes building new nests to those repairing old nests and found that new nests require more time and effort to build. Similarly, previous workers found that adherent nests took more time and effort to build than statant nests. At the same time, these workers noted that smaller clutches were laid in new and adherent nests than in repaired and statant nests and concluded that the reduction in clutch size was the result of building the former types of nest. This implies that an increase in the demands on parental time and energy just before egg laying can decrease reproductive output proximally. However, the statistical support for this conclusion was weak, and our reanalysis of the previously reported data does not support it. In addition, previous workers used the terms statant and adherent inconsistently. We advise that nest types be carefully defined according to the expected effect of nest type on the bird's behaviour, not just according to the appearance of the nest. We found that building new nests took longer than repairing old ones. However, we failed to find a difference in the time required to build adherent and statant nests. Furthermore, clutch size was apparently unrelated to the type of nest built. We found no relationship of clutch size to female age or clutch initiation date. The type of nest built for the first clutch size of the season also was not related to the probability that there would be a second clutch, the size of the second clutch, or the interval between clutches. More research is required to show conclusively that increased demands on time or energy just before egg laying can reduce the clutch size of small passerines.
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Gloag, Ros, Vanina D. Fiorini, Juan C. Reboreda, and Alex Kacelnik. "Brood parasite eggs enhance egg survivorship in a multiply parasitized host." Proceedings of the Royal Society B: Biological Sciences 279, no. 1734 (December 7, 2011): 1831–39. http://dx.doi.org/10.1098/rspb.2011.2047.
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Despite the costs to avian parents of rearing brood parasitic offspring, many species do not reject foreign eggs from their nests. We show that where multiple parasitism occurs, rejection itself can be costly, by increasing the risk of host egg loss during subsequent parasite attacks. Chalk-browed mockingbirds ( Mimus saturninus ) are heavily parasitized by shiny cowbirds ( Molothrus bonariensis ), which also puncture eggs in host nests. Mockingbirds struggle to prevent cowbirds puncturing and laying, but seldom remove cowbird eggs once laid. We filmed cowbird visits to nests with manipulated clutch compositions and found that mockingbird eggs were more likely to escape puncture the more cowbird eggs accompanied them in the clutch. A Monte Carlo simulation of this ‘dilution effect’, comparing virtual hosts that systematically either reject or accept parasite eggs, shows that acceptors enjoy higher egg survivorship than rejecters in host populations where multiple parasitism occurs. For mockingbirds or other hosts in which host nestlings fare well in parasitized broods, this benefit might be sufficient to offset the fitness cost of rearing parasite chicks, making egg acceptance evolutionarily stable. Thus, counterintuitively, high intensities of parasitism might decrease or even reverse selection pressure for host defence via egg rejection.
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Preston, Kristine L., and John T. Rotenberry. "The Role of Food, Nest Predation, and Climate in Timing of Wrentit Reproductive Activities." Condor 108, no. 4 (November 1, 2006): 832–41. http://dx.doi.org/10.1093/condor/108.4.832.
Full textAbstract:
Abstract Abstract Timing of breeding activities by birds hasimportant fitness consequences, as deciding when tonest can affect nest success. For three breedingseasons, we provided supplemental food to Wrentits(Chamaeafasciata) inhabitingsemiarid shrublands. We tested the effects of foodsupplementation on timing of initial egg laying,number of nests attempted, timing of fledging, andlength of the breeding season. We also evaluatedwhether Wrentits timed nest initiation to avoidperiods of greatest predation risk. Our study wasconducted during a period of high interannualvariation in precipitation. Supplemental food didnot advance laying date in Wrentits. During adrought, even Wrentits given supplemental fooddelayed nesting, initiated fewer nesting attempts,fledged young earlier, and reduced the length ofthe breeding season. In a year of average rainfall,supplemental food allowed pairs to continuerenesting late into the summer, after repeated nestlosses from predation. Wrentits did not timenesting to avoid periods of greatest predationrisk. In timing initial breeding, Wrentits appearedto be responding to climatic conditions and toindirect cues that predicted environmentalconditions later in the breeding season rather thanto food availability at the time of egg laying.
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Bjørn, Tor Harry, and Kjell Einar Erikstad. "Patterns of intraspecific nest parasitism in the High Arctic common eider (Somateria mollissima borealis)." Canadian Journal of Zoology 72, no. 6 (June 1, 1994): 1027–34. http://dx.doi.org/10.1139/z94-139.
Full textAbstract:
Intraspecific nest parasitism was studied during two breeding seasons at two common eider (Somateria mollissima borealis) colonies in Kongsfjord, Svalbard (79°55′N, 12°10′E). The density of breeding eiders differed considerably from year to year and also among colonies. Parasitic eggs were identified through deviations from a normal laying pattern. Parasitic eggs (8%) were laid in 16% of the clutches at the dense colony. The corresponding values on the island with low breeding density were 1.6 and 2% in 1989 and 1990, respectively. Parasitic eggs were laid in clutches of all sizes according to their availability. The parasitizing females laid 70% of their eggs during the host's laying period. Parasitic laying occurred despite the constant availability of suitable nest sites. The hosts did not reduce their clutch size in response to egg parasitism. The rate of egg predation was significantly higher in parasitized than in nonparasitized nests. Parasitic eggs were laid late in the breeding period, suggesting that birds which were immature, in poor body condition, or had previously failed are salvaging some reproductive effort.
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Becot, Lorry, Nicolas Bedere, Thierry Burlot, Jenna Coton, and Pascale Le Roy. "Nest acceptance, clutch, and oviposition traits are promising selection criteria to improve egg production in cage-free system." PLOS ONE 16, no. 5 (May 20, 2021): e0251037. http://dx.doi.org/10.1371/journal.pone.0251037.
Full textAbstract:
In cage-free systems, laying hens must lay their eggs in the nests. Selecting layers based on nesting behavior would be a good strategy for improving egg production in these breeding systems. However, little is known about the genetic determinism of nest-related traits. Laying rate in the nests (LRN), clutch number (CN), oviposition traits (OT), and nest acceptance for laying (NAL) of 1,430 Rhode Island Red (RIR) hens and 1,008 White Leghorn (WL) hens were recorded in floor pens provided with individual electronic nests. Heritability and genetic and phenotypic correlations of all traits were estimated over two recording periods–the peak (24–43 weeks of age) and the middle (44–64 weeks of age) of production–by applying the restricted maximum likelihood method to an animal model. The mean oviposition time (MOT) ranged from 2 h 5 min to 3 h and from 3 h 35 min to 3 h 44 min after turning on the lights for RIR and WL hens, respectively. The mean oviposition interval ranged from 24 h 3 min to 24 h 16 min. All heritability and correlation estimates were similar for RIR and WL. Low to moderate heritability coefficients were estimated for LRN (0.04–0.25) and moderate to high heritability coefficients for CN and OT (0.27–0.68). CN and OT were negatively genetically correlated with LRN (-0.92 to -0.39) except during peak production for RIR (-0.30 to +0.43). NAL was weakly to moderately heritable (0.13–0.26). Genetic correlations between NAL and other traits were low to moderate (-0.41 to +0.44). In conclusion, CN and OT are promising selection criteria to improve egg production in cage-free systems. NAL can be also used to reduce the number of eggs laid off-nest in these breeding systems. However, variability in MOT must be maintained to limit competition for the nests.
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Doniyorov, Boymurad N. "INFORMATION ON THE BIOLOGY OF ACRIDOTHERES TRISTIS." Oriental Journal of Biology and Chemistry 02, no. 02 (October 1, 2022): 1–8. http://dx.doi.org/10.37547/supsci-ojbc-02-02-01.
Full textAbstract:
The relevance of the topic in the article, the distribution of Acridotheres tristis, mating characteristics and its study, the duration of the research and the methods used in the work, the number of nests found, nesting places, mating places and their number, mating, breeding behavioral responses, number and location of nests, nesting interspecific relationships, nesting duration and use, nest shape, dimensions, nest location, nest construction, nest components and morphometric dimensions, egg laying and duration and brood care during incubation, changes in the egg, hatching, chick size, growth and development, reproduction images, relationship of the new generation to the nest , information about the night, relations with historical monuments, biological characteristics such as nutrition and food types and their importance were studied.
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ODA, Welton Yudi. "Communal egg laying by Gonatodes humeralis (Sauria, Gekkonidae) in Manaus primary and secondary forest areas." Acta Amazonica 34, no. 2 (2004): 331–32. http://dx.doi.org/10.1590/s0044-59672004000200020.
Full textAbstract:
Communal nesting has been registered for a number of lizard species at different sites. Here it is described communal egg laying of Gonatodes humeralis at different sites near and in human buildings in the period between 1990 and 1998. All these communal nests have been found in the dry season, between April and July, suggesting that the nests of are more common in this season, when the activity of their predators is less intense and the reduction of humidity diminish the decomposition action of the fungi that may kill the eggs.
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Wang, Longwu, Canchao Yang, Yu-Cheng Hsu, Anton Antonov, Arne Moksnes, Eivin Røskaft, Wei Liang, and Bård Gunnar Stokke. "Increase of clutch size triggers clutch destruction behaviour in common moorhens (Gallinula chloropus) during the incubation period." Behaviour 150, no. 2 (2013): 215–23. http://dx.doi.org/10.1163/1568539x-00003046.
Full textAbstract:
Conspecific brood parasitism (CBP) is common in a variety of animal taxa, including birds. In coots (Fulica spp.), and the closely related moorhens (Gallinula spp.), such parasitism is especially common, and hosts experience considerable costs through increased chick competition soon after hatching. Hence, these birds have evolved egg recognition and rejection abilities, e.g., egg counting, burying the foreign eggs, assigning them suboptimal positions within the mixed clutch, or deserting parasitized clutches. For common moorhens (Gallinula chloropus) it has been shown that desertion of parasitized nests pays most at the early egg laying stage. Later on, the costs of desertion exceed the costs of brood parasitism and acceptance is favoured. Here we tested moorhen egg discrimination behaviour during the incubation stage when acceptance of foreign eggs is expected. Four treatments were applied: (1) single added non-mimetic pale blue egg, (2) single added non-mimetic white chicken egg, (3) four foreign conspecific eggs added to the clutch and (4) four foreign conspecific eggs exchanged for four host eggs. Moorhens responded by egg destruction (47%) only to the increased clutch size but not to foreign egg colour and size match. In three nests where egg destruction occurred, all the eggs in the mixed clutch were destroyed by pecking, in two other nests one of the foreign eggs were pecked, while two other nests were deserted. These results are puzzling since moorhens have been shown to possess refined egg recognition abilities. To our knowledge, such destruction of parasitized clutches by moorhens during incubation has not previously been reported. We suggest that after clutch completion, moorhens use increase in clutch size as a cue to determine if they have been parasitized, and some individuals choose to reject parasitic eggs by deserting or destroying the whole clutch.
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Karim, Hadijah. "Vegetation Characteristics of The Maleo Bird (Macrochepalon Maleo) Habitat at Natural Tourism Park of Towuti Lake, South Sulawesi." Jurnal Wasian 9, no. 1 (June 29, 2022): 63–73. http://dx.doi.org/10.20886/jwas.v9i1.6375.
Full textAbstract:
Maleo birds (Macrocephalon maleo) generally have habitats in forests near hot springs, but in East Luwu Regency their habitat is found on the shores of Lake Towuti. It is suspected that the habitat of maleo birds at the site has different characteristics. This study aims to identify the vegetation characteristics of maleo bird habitat in the sleeping area and tread where to lay eggs. Vegetation analysis was carried out by purposive sampling with a plot size of 20 m x 20 m in the sleeping area, and 5 m x 5 m in the laying site where the egg-laying was located. The data collected are the name of the type, diameter, the individual number of trees, poles, stakes, and seedlings. The results showed that in sleeping areas, macadamia hildebrandii trees have the highest INP values. Macadamia hildebrandii fruit is thought to be one of [1]the feeds for Maleo birds. In egg-laying habitats, Imperata cylindrica has the highest INP compared to other types. On the tread of the egg-laying nests can be seen maleo birds eating grass grains. There are differences in ecological index [2]values found in sleeping habitats, namely H'= 2.24 (medium), Dmg= 3.02 (low), and E= 0.81 (high). However, in egg-laying habitats, the Ecological Index values found were H'= 0.62 (low), Dmg= 0.93 (low) and E= 0.30 (low). The discovery of maleo birds in Lake Towuti TWA makes the area one of the remaining in situ habitats in South Sulawesi and can be a consideration for the government to maintain and preserve it.
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Martins, Marcio. "Observations on nest dynamics and embryonic and larval development in the nest building gladiator frog, Hyla faber." Amphibia-Reptilia 14, no. 4 (1993): 411–21. http://dx.doi.org/10.1163/156853893x00101.
Full textAbstract:
AbstractNests and larval development of the nest building gladiator frog, Hyla faber were studied in southeastern Brazil, during the rainy season of 1988-1989. Nests were built at the pond margins, exclusively by males, and varied in shape, size, and composition in relation to the substrate. Nests were used by 1-4 individual males and housed larvae for a mean of 26 days; 0-6 egg clutches were deposited in a nest. Larvae from individual clutches stayed inside the nests for 8-38 days. Embryonic development occurred within the first 210 h after fertilization and larval development, inside an enclosure installed in a pond, lasted over 8 months. Mortality inside the nests was due to nest water evaporation and/or drainage, to eggs sinking in the first hours after fertilization, or to predation by aquatic insects. Slow larval development in Hyla faber seems to be related to breeding in permanent ponds. Nest building in Hyla faber and related species may have evolved from the habit of using natural depressions for egg laying observed in other morphologically similar species.
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Izadjoo, Mina J., Carmen O. A. Pantoja, and R. J. Siebeling. "Acquisition of Salmonella flora by turtle hatchlings on commercial turtle farms." Canadian Journal of Microbiology 33, no. 8 (August 1, 1987): 718–24. http://dx.doi.org/10.1139/m87-125.
Full textAbstract:
A commercial turtle pond in South Louisiana was studied to identify the mechanism by which turtle hatchlings acquire Salmonella flora. The visceral organs and mature eggs removed from 31 adult gravid female turtles over the course of two egg-laying seasons and from 37 adult females during one winter dormant period were examined bacteriologically for Salmonella. Pond water, egg nest soil, and hatchlings produced by eggs removed from the oviducts and nest soil were also tested. Eighty-eight turtles hatched from eggs removed from the oviducts of 15 turtles at necropsy did not excrete or harbor systemically Salmonella, nor were these pathogens isolated from ovarian tissue or immature eggs. The findings suggest transovarian transmission of these pathogens does not occur frequently. Turtles hatched from eggs retrieved from soil nests 1 to 2 h after deposition harbor and excrete these organisms. This result coupled with the isolation of these pathogens from the cloaca, colon contents, and bursal fluid from 18 females captured in the act of egg laying supports the cloaca to egg and nest soil to egg mode for salmonellae infection in the resultant hatchling. Salmonella arizonae and Salmonella serogroups B, C2, and E1 were isolated from the cloaca, colon contents, pond water, and nest soil, and were excreted by hatchlings produced from eggs removed from the soil nests. These same serogroups were isolated from the colon contents of 19 of 37 females tested during the dormant period, suggesting the salmonellae persist in the pond environment in the adult throughout the year.
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Welty, J. L., J. R. Belthoff, J. Egbert, and H. Schwabl. "Relationships between yolk androgens and nest density, laying date, and laying order in Western Burrowing Owls (Athene cunicularia hypugaea)." Canadian Journal of Zoology 90, no. 2 (February 2012): 182–92. http://dx.doi.org/10.1139/z11-125.
Full textAbstract:
Increases in yolk androgens within and among avian clutches have been correlated with decreased incubation time, increased aggression within a nest, increased begging behaviour, decreased immune response, and decreased life span. Although the mechanisms that lead to variability in yolk androgens within and between clutches are not completely known, yolk androgens can be a function of both social and environmental conditions. We were interested in if and how nesting density, laying date, and laying order influenced yolk androgens in Western Burrowing Owls ( Athene cunicularia hypugaea (Bonaparte, 1825)) in which nest density varies considerably. In 2006 and 2007, we used radioimmunoassay to quantify the concentrations of testosterone, 5α-dihydrotestosterone, and androstenedione in the egg yolks from one early and one late-laid egg in 47 nests of Burrowing Owls located in the Morley Nelson Snake River Birds of Prey National Conservation Area in southern Idaho. Nesting density had no detectable effect on yolk androgens. Yolk androgens varied temporally and peaked in the middle of the laying season while being low before and after this time period. Within nests, late-laid eggs had higher testosterone and dihydrotestosterone than early-laid eggs; adrostendione exhibited a similar pattern in one but not both years of our study. It is possible that the seasonal pattern in yolk androgens that we observed is related to aspects of mate quality for females or declining chances of fledging success for later nesting females, whereas rises in egg androgens between early and late eggs within clutches could reflect a mechanism to assist nestlings from late-laid eggs that hatch one to several days after their siblings to better compete for resources within the nest or promote survival in the presence of larger siblings.