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1
Dijkstra, Thomas, Peter Korsten und Jan Komdeur. „Is UV signalling involved in male-male territorial conflict in the blue tit (Cyanistes caeruleus)? A new experimental approach“. Behaviour 144, Nr. 4 (2007): 447–70. http://dx.doi.org/10.1163/156853907780756030.
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Structurally-based ultraviolet (UV) coloration of plumage can signal male quality and plays a role in female mate choice in many bird species. UV-reflecting badges could also be important signals in male-male competition. We tested if territorial blue tit ( Cyanistes caeruleus ) males discriminate between conspecific male intruders which differ in the UV reflectance of their crown feathers. To this aim, we used a new experimental approach in which we simultaneously (instead of sequentially) introduced two male blue tit taxidermic mounts in the territories of resident males during the female fertile period; one mount with natural crown UV reflectance and one mount with reduced crown UV. The two mounts provoked strong aggressive reactions from resident males. Males specifically directed their aggression to conspecific intruders, as a male blue tit mount received substantially more aggression than a mount of a European robin ( Erithacus rubecula ). However, aggression of resident males did not vary between the UV-reduced and the control mount. Furthermore, the variation in natural crown UV reflectance of the resident males did not predict the intensity of their aggressive response. Contrary to previous findings our results suggest that UV signals play only a limited role in male-male interactions during territorial intrusions in the female fertile period.
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Hof, David, und Jeffrey Podos. „Escalation of aggressive vocal signals: a sequential playback study“. Proceedings of the Royal Society B: Biological Sciences 280, Nr. 1768 (07.10.2013): 20131553. http://dx.doi.org/10.1098/rspb.2013.1553.
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Rival conspecifics often produce stereotyped sequences of signals as agonistic interactions escalate. Successive signals in sequence are thought to convey increasingly pronounced levels of aggressive motivation. Here, we propose and test a model of aggressive escalation in black-throated blue warblers, presenting subjects with two sequential and increasingly elevated levels of threat. From a speaker outside the territorial boundary, we initiated an interaction (low-threat level), and from a second speaker inside the territory, accompanied by a taxidermic mount, we subsequently simulated a territorial intrusion (escalated threat level). Our two main predictions were that signalling behaviours in response to low-threat boundary playback would predict signalling responses to the escalated within-territory threat, and that these latter signalling behaviours would in turn reliably predict attack. We find clear support for both predictions: (i) specific song types (type II songs) produced early in the simulated interaction, in response to boundary playback, predicted later use of low-amplitude ‘soft’ song, in response to within-territory playback; and (ii) soft song, in turn, predicted attack of the mount. Unexpectedly, use of the early-stage signal (type II song) itself did not predict attack, despite its apparent role in aggressive escalation. This raises the intriguing question of whether type II song can actually be considered a reliable aggressive signal. Overall, our results provide new empirical insights into how songbirds may use progressive vocal signalling to convey increasing levels of threat.
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Akçay, Çağlar, S. Elizabeth Campbell und Michael D. Beecher. „Individual differences affect honest signalling in a songbird“. Proceedings of the Royal Society B: Biological Sciences 281, Nr. 1775 (22.01.2014): 20132496. http://dx.doi.org/10.1098/rspb.2013.2496.
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Research in the past decade has established the existence of consistent individual differences or ‘personality’ in animals and their important role in many aspects of animal behaviour. At the same time, research on honest signalling of aggression has revealed that while some of the putative aggression signals are reliable, they are only imperfectly so. This study asks whether a significant portion of the variance in the aggression-signal regression may be explained by individual differences in signalling strategies. Using the well-studied aggressive signalling system of song sparrows ( Melospiza melodia ), we carried out repeated assays to measure both aggressive behaviours and aggressive signalling of territorial males. Through these assays, we found that aggressive behaviours and aggressive signalling were both highly repeatable, and moreover that aggressive behaviours in 2009–2010 predicted whether the birds would attack a taxidermic mount over a year later. Most significantly, we found that residual variation in signalling behaviours, after controlling for aggressive behaviour, was individually consistent, suggesting there may be a second personality trait determining the level of aggressive signalling. We term this potential personality trait ‘communicativeness’ and discuss these results in the context of honest signalling theories and recent findings reporting prevalence of ‘under-signalling’.
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Akçay, Çağlar, und Michael D. Beecher. „Multi-modal communication: song sparrows increase signal redundancy in noise“. Biology Letters 15, Nr. 10 (Oktober 2019): 20190513. http://dx.doi.org/10.1098/rsbl.2019.0513.
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Although the effects of anthropogenic noise on animal communication have been studied widely, most research on the effect of noise in communication has focused on signals in a single modality. Consequently, how multi-modal communication is affected by anthropogenic noise is relatively poorly understood. Here, we ask whether song sparrows ( Melospiza melodia ) show evidence of plasticity in response to noise in two aggressive signals in acoustic and visual modalities. We test two hypotheses: (i) that song sparrows will shift signalling effort to the visual modality (the multi-modal shift hypothesis) and (ii) that they will increase redundancy of their multi-modal signalling (the back-up signal hypothesis). We presented male song sparrows with song playback and a taxidermic mount with or without a low-frequency acoustic noise from a nearby speaker. We found that males did not switch their signalling effort to visual modality (i.e. wing waves) in response to the noise. However, the correlation between warbled soft songs and wing waves increased in the noise treatment, i.e. signals became more redundant. These results suggest that when faced with anthropogenic noise, song sparrows can increase the redundancy of their multi-modal signals, which may aid in the robustness of the communication system.
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Cartar, Ralph V., und R. I. Guy Morrison. „Estimating metabolic costs for homeotherms from weather data and morphology: an example using calidridine sandpipers“. Canadian Journal of Zoology 75, Nr. 1 (01.01.1997): 94–101. http://dx.doi.org/10.1139/z97-012.
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It is often desirable to estimate the metabolic costs incurred by homeothermic organisms of differing morphology living in different real or hypothetical environmental conditions. To address this problem, we describe a method, based on previously published empirical allometric and heat-transfer equations, that allows a rough estimate to be made of the daily maintenance metabolic costs (i.e., basal and thermoregulatory costs) incurred by a bird in a simple cold two-dimensional environment. The model uses widely available weather variables (temperature, wind speed, and global solar radiation), morphological variables (body mass, height of body's centre of gravity, diameter of torso), and a habitat variable (height of vegetation). We apply the model to weather data from the Canadian Arctic to predict daily metabolic costs for two calidridine sandpiper species (Calidris canutus and C. minutilla) during the summer. The model is extremely sensitive to error in the slope and intercept of the allometric equation predicting conductance from body mass, but is generally robust to other model parameters. Using ambient temperature (Ta) in place of operative temperature (Te) has only a minor (3.5%) effect on predicted metabolic costs, so, given that Te is difficult to estimate, we recommend this substitution (at least for arctic latitudes, where solar radiation is of reduced importance). The model predicts metabolic rates similar to those obtained from an equation based on a heated taxidermic mount for C. canutus, thereby providing some measure of validation. The model can easily be modified to predict metabolic costs for other groups of birds or mammals.
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Casado, Santos, und Santiago Aragón. „Vignettes of Spanish Nature“. Historical Studies in the Natural Sciences 44, Nr. 3 (November 2012): 197–233. http://dx.doi.org/10.1525/hsns.2014.44.3.197.
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Taxidermy played a pivotal role in the renewal of the Spanish Museo Nacional de Ciencias Naturales in Madrid during the first few decades of the twentieth century. This essay examines the work of the brothers José María Benedito (1873–1951) and Luis Benedito (1884–1955) and their part in the making of a remarkable series of biological groups and habitat dioramas, mainly devoted to the most characteristic species of Spanish fauna. The Benedito brothers’ taxidermy mounts can be viewed as an attempt to construct a new image of a national fauna. From this point of view, taxidermic practices appear as an integral component of an ambitious educational and cultural project, with their foundations in the scientific work of the museum’s zoologists, and aimed at a broad, educated public, at a time of widespread political effort to reinvigorate Spanish society. Indeed, efforts to regenerate a troubled Spanish national identity and to promote science and education as drivers of social progress are typical of the critical turn-of-the-century period. In this context, the Benedito brothers’ work at the museum can be related both to an international trend to modernize natural history displays in museums around the world, and to more specific cultural and scientific developments characteristic of the processes of modernization at work in early twentieth-century Spanish society. Modern taxidermy, it is argued, has been incorporated in various ways into political and cultural discourses contingent on national contexts, while at the same time its technical procedures have remained essentially unchanged.
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Bakken, George S., Kevin P. Kenow, Carl E. Korschgen und Andrew F. Boysen. „Statistical and procedural issues in the use of heated taxidermic mounts“. Journal of Thermal Biology 25, Nr. 4 (August 2000): 317–21. http://dx.doi.org/10.1016/s0306-4565(99)00094-7.
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Greek, Thomas J., Kyaw Tha Paw U und Wesley W. Weathers. „A comparison of operative temperature estimated by taxidermic mounts and meteorological data“. Journal of Thermal Biology 14, Nr. 1 (Januar 1989): 19–26. http://dx.doi.org/10.1016/0306-4565(89)90025-9.
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Eliason, Stephen L. „Reconstructing Dead Nonhuman Animals: Motivations for Becoming a Taxidermist“. Society & Animals 20, Nr. 1 (2012): 1–20. http://dx.doi.org/10.1163/156853012x614332.
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Abstract Displays of dead nonhuman animals are a common sight on the walls of many American homes and commercial establishments. Taxidermists are the individuals who preserve and attempt to re-create dead animals, birds, and fish so they can be displayed. Little is known about those employed in the profession, including characteristics of individuals who enter this line of work. Using a qualitative approach to data collection, this exploratory research examined motivations for becoming a taxidermist in Montana. Findings suggest that Montana taxidermists entered the profession for one of five main reasons: an interest in wildlife, a desire to mount their own trophies, a hobby that became a job, the necessity of changing jobs, and miscellaneous motivations.
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Sullivan, Steven M., Wesley Skidmore und George Dante. „Authenticity in an Uncertain World: Ensuring Accuracy in both the Explicit and Implicit Messages of Exhibits“. Biodiversity Information Science and Standards 2 (13.06.2018): e25785. http://dx.doi.org/10.3897/biss.2.25785.
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Do you know what a kiwi looks like - all the way down to the orientation of the nostrils? While small details won’t make or break the aesthetics of an exhibit, they can have important impacts on visitor learning and future behavior. Museums are a traditional bastion of authenticity. From the objects we exhibit to the information we share, audiences know that museums are a trustworthy source of real objects and vetted facts. We strive to ensure accurate label copy, but the traditional constraints of preservation and exhibition of natural history specimens can still convey confusing or implicitly inaccurate information. Problems like sub-standard taxidermy, faded mounts, heedless application of plants, and inaccurate social groupings abound in museums. Visitors are usually not equipped to evaluate such details, yet such details often become a baseline from which visitor’s expectations of nature are derived. Therefore, accurate representations of species are an important way to convey both explicit institutional messages and implicit information about nature. We will discuss the fundamental details that differentiate award-winning taxidermy from substandard representations of the species. We will show how to employ a few, fundamental principles to overcome the constraints of preservation to make mounts, dioramas, and artificial reproductions as exciting, beautiful, and accurate as possible.
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Larochelle, Jacques. „Comments on a Negative Appraisal of Taxidermic Mounts as Tools for Studies of Ecological Energetics“. Physiological Zoology 71, Nr. 5 (September 1998): 596–98. http://dx.doi.org/10.1086/515951.
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12
Lindholm, Anna, und Robert Thomas. „BETWEEN POPULATIONS OF REED WARBLERS IN DEFENCES AGAINST BROOD PARASITISM“. Behaviour 137, Nr. 1 (2000): 25–42. http://dx.doi.org/10.1163/156853900501854.
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AbstractTwo potential defences against brood parasitism by the cuckoo Cuculus canorus were compared experimentally between British populations of reed warblers Acrocephalus scirpaceus that are parasitised at different rates. (1) Rates of rejection of model cuckoo eggs were lower at two unparasitised populations which did not have resident cuckoos, than at a rarely parasitised population which had cuckoos nearby, and at a regularly parasitised population. (2) Reed warblers from an unparasitised population showed a slightly weaker response to taxidermic mounts of cuckoos and, unlike a parasitised population, did not differentiate between mounts of a cuckoo, sparrowhawk Accipiter nisus and jay Garrulus glandarius . Differences in exposure to real predators may explain the differences in responses to mounted predators between populations, as specific aggressive responses to predators are likely to have been learned. Although evidence from dispersal and population turnover data suggests that there is likely to be gene flow between reed warbler populations in Britain, the hypothesis that the population differences reflect genotypic differences could not be ruled out. An alternative explanation of phenotypic plasticity in defences could also explain the population differences. Phenotypic plasticity in defences would be favoured in environments where the risk of parasitism fluctuates, if those defences are costly to unparasitised reed warblers.
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Kabat, Alan R. „Richard Frederick Deckert (1878–1971), Florida naturalist and natural history artist“. Archives of Natural History 39, Nr. 2 (Oktober 2012): 321–37. http://dx.doi.org/10.3366/anh.2012.0098.
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Richard Deckert (born in Germany in 1878, immigrated to New York in 1887, died in Florida in 1971) was a polymath with great enthusiasm and wide ranging interests in natural history. His collections and publications did much to document the reptiles, amphibians, and land snails of Florida. His contributions to natural history illustration were equally important, as his carefully detailed line drawings and water colour paintings delineated the intricate details of snails, fishes, amphibians, and reptiles (particularly snakes and turtles), as well as fossil vertebrates, and were used in a wide range of systematic publications. Deckert also contributed to the modernization of fish taxidermy, leading to the current methods for creating lifelike fish mounts. This paper documents his scientific and artistic work.
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Gill, Sharon A., und Spencer G. Sealy. „Nest Defence By Yellow Warblers: Recognition of a Brood Parasite and an Avian Nest Predator“. Behaviour 133, Nr. 3-4 (1996): 263–82. http://dx.doi.org/10.1163/156853996x00143.
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AbstractYellow warblers (Dendroica petechia) were exposed to taxidermic mounts of a brood parasite (brown-headed cowbird, Molothrus ater), avian nest predator (common grackle, Quiscalus quiscula) and control (fox sparrow, Passerella iliaca) during their laying and nestling stages to determine whether nest owners distinguish between the threats of brood parasitism and predation. Yellow warblers responded more intensely to the cowbird at the laying stage, performing two unique behaviours (seet calling and nest-protection behaviour) in response to this threat. By contrast, yellow warbler responses to the grackle were greater at the nestling stage, consisting largely of alarm calls (chip, metallic chip and warble calls). The sparrow model infrequently elicited aggressive behaviour from nest owners at either stage. These responses support the hypothesis that yellow warblers discriminate between threats of brood parasitism and nest predation. Yellow warblers may perform specific behaviours to cowbirds because defensive behaviours used against predators may be incompatible with cowbird deterrence. Female nest owners responded more frequently than males at the laying stage, and more intensely than males at both nesting stages. The distance that females and males approached the models and several aggressive behaviours were positively correlated. The greater responsiveness of females may be because they dominate their mates and because females are more experienced with intruders near the nest.
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Fortin, Daniel, und Gilles Gauthier. „The effect of postural adjustment on the thermal environment of greater snow goose goslings“. Canadian Journal of Zoology 78, Nr. 5 (01.05.2000): 817–21. http://dx.doi.org/10.1139/z00-002.
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This study examines how changing from a standing to a sitting posture influences the thermal environment of greater snow goose goslings (Chen caerulescens atlantica). This was investigated by estimating the standard operative temperature of four heated taxidermic mounts (3, 10, 20, and 30 d old) exposed to various wind velocities (0-5 m/s) and ground (16-23°C) and air (0-15°C) temperatures, in three orientations (head, flank, or tail toward the wind) and two postures (sitting and standing). Changes in posture influenced both conductive and convective heat exchanges. At low wind speeds, sitting on the sand reduced the standard operative temperature of goslings, while at high wind speeds sitting enhanced this temperature index. We calculated that a net thermal gain would be obtained by sitting on cold sand at air temperatures of 5, 10, and 15°C when the wind speed exceeded 3 m/s for most orientations toward the incoming wind. However, this critical wind speed would be 23% lower following a 7°C increase in ground temperature. Our study suggests that postural changes can have important consequences on goslings' thermal environment. It also stresses the importance of considering the synergistic impact of conductive and convective heat transfer processes, when studying the impact of postural changes on thermal environments.
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Groenewoud, Frank, Sjouke A. Kingma, Kat Bebbington, David S. Richardson und Jan Komdeur. „Experimentally induced antipredator responses are mediated by social and environmental factors“. Behavioral Ecology 30, Nr. 4 (12.04.2019): 986–92. http://dx.doi.org/10.1093/beheco/arz039.
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AbstractNest predation is a common cause of reproductive failure for many bird species, and various antipredator defense behaviors have evolved to reduce the risk of nest predation. However, trade-offs between current reproductive duties and future reproduction often limit the parent’s ability to respond to nest predation risk. Individual responses to experimentally increased nest predation risk can give insights into these trade-offs. Here, we investigate whether social and ecological factors affect individual responses to predation risk by experimentally manipulating the risk of nest predation using taxidermic mounts in the cooperative breeding Seychelles warbler (Acrocephalus sechellensis). Our results show that dominant females, but not males, alarm called more often when they confront a nest predator model alone than when they do so with a partner, and that individuals that confront a predator together attacked more than those that did so alone. Dominant males increased their antipredator defense by spending more time nest guarding after a presentation with a nest predator, compared with a nonpredator control, but no such effect was found for females, who did not increase the time spent incubating. In contrast to incubation by females, nest guarding responses by dominant males depended on the presence of other group members and food availability. These results suggest that while female investment in incubation is always high and not dependent on social and ecological conditions, males have a lower initial investment, which allows them to respond to sudden changes in nest predation risk.
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Sealy, Spencer G., und Diane L. Neudorf. „Reactions of Four Passerine Species To Threats of Predation and Cowbird Parasitism: Enemy Recognition or Generalized Responses?“ Behaviour 123, Nr. 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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Allen, Maximilian L., Nathan M. Roberts und Timothy R. Van Deelen. „Hunter selection for larger and older male bobcats affects annual harvest demography“. Royal Society Open Science 5, Nr. 10 (Oktober 2018): 180668. http://dx.doi.org/10.1098/rsos.180668.
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Wildlife researchers often rely on demographic data collected from harvested animals to estimate population dynamics. But demographic data from harvested animals may be non-representative if hunters/trappers have the ability and motivation to preferentially select for certain physical traits. Hunter preference is well demonstrated for ungulates, but less so for other wildlife species such as furbearers. We used data from bobcats harvested in Wisconsin (1983–2014) to determine if harvest method and demographics (mass, male:female sex ratio and age) have changed over time, and if bobcat hunters/trappers exhibited selection. Each trait of harvested bobcats that we tested changed over time, and because these selected traits were interrelated, we inferred that harvest selection for larger size biased harvests in favour of older, male bobcats. The selection of older, male bobcats appears primarily driven by hound hunters (hereafter hunters) compared to trappers, with hunters more frequently creating taxidermy mounts from their harvested bobcats. We found an increase in the proportion of bobcats that were harvested by hunting compared to trapping over time, and this was associated with increased selectivity and substantial changes in the characteristics of harvested bobcats. Selection by hunters may bias population models that are based on the demography of harvested bobcats, and accounting for biases that may occur, including from different harvest methods, is critical when using harvest-dependent data.
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Kalb, Nadine, Fabian Anger und Christoph Randler. „Great tits encode contextual information in their food and mobbing calls“. Royal Society Open Science 6, Nr. 11 (November 2019): 191210. http://dx.doi.org/10.1098/rsos.191210.
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The calling behaviour of Paridae species (i.e. titmice, tits and chickadees) in a predator-related context is well-studied. Parid species are known to alter call types, note composition or call duration according to predation risk. However, how these species encode information about a non-threatening context, such as food sources, has been subject to only few studies. Studies in Carolina chickadees ( Poecile carolinensis ) have shown that this species alters the ratio of C and D notes to encode information about the presence of food and/or the flight behaviour of the signaller. This suggests that parids also use graded signals to encode information about non-predatory contexts. No study to date has directly compared the calls of a feeding context with those of a predation (i.e. mobbing) context. Hence, the aim of this study was to compare the calling behaviour of these two situations in great tits ( Parus major ). Calls uttered at a feeder were recorded, analysed and compared with calls uttered in front of taxidermy mounts of sparrowhawks ( Accipiter nisus ). In the food context, great tits reduced the number of D notes and increased the number of B, C and E notes compared with the mobbing context. Furthermore, tits produced calls with longer D notes and shorter intervals between D notes than in the mobbing context. This indicates that great tits use two mechanisms of graded signals (i.e. note type and acoustic structure of D calls) to inform conspecifics about the nature of a situation.
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Elliot, Richard D. „The Effects of Predation Risk and Group Size On the Anti-Predator Responses of Nesting Lapwings Vanellusvanellus“. Behaviour 92, Nr. 1-2 (1985): 168–87. http://dx.doi.org/10.1163/156853985x00433.
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The anti-predator responses of nesting lapwings were studied near Newburgh, Aberdeenshire, Scotland, using taxidermy mounts of a carrion crow, great black-backed gull, and red fox pulled towards their nests. Lapwings appeared to respond to these dummies and to a control woodpigeon as they would to the live animals. Responses to nest predators that are relatively harmless to adult lapwings, represented by the crow, included initial investigative flights. These quickly changed to diving attacks, over 60% of which actually struck the dummy predator. In response to the fox, which is a threat to both the adults and the eggs, lapwings never made physical contact, but circled overhead, or attempted to lead or distract the predator on the ground. Responses to the fox were similar in daylight and darkness, but lapwings did not respond to the dummy crow at night. Both diving and distraction responses to the gull were observed. Thus the closeness of attack was inversely related to the risk that the live predator would have posed to the adults. The intensity of response to the dummy crow increased through the incubation period and breeding season, as predicted on the basis of a decreasing difference between the reproductive value of the adults and the clutch they were protecting, resulting in the defenders under-taking increasingly greater risks. Both the number of lapwings responding to the crow, and the distances from the nest at which high intensity responses occurred, increased with the size of the nesting aggregation, ranging from one to five pairs, but not with the number of birds present prior to the experiment. Both these effects should lead to a higher probability of successfully repelling a crow with increasing group size. The area in which diving attacks occurred extended to 40-60 m from the nest in larger groups. Neither relationship was found in experiments with the dummy fox, in which all high intensity responses were performed by one adult only. Nesting in loose aggregations thus seems to enhance the effectiveness of the lapwings' responses to nest predators such as crows, but not to more dangerous predators such as the fox.
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FORTIN, D. „The use heated taxidermic mounts in studies of ecological energetics“. Mammalia 65, Nr. 2 (2001). http://dx.doi.org/10.1515/mamm.2001.65.2.195.
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