Journal articles: 'Radio-tagged animals'

1

Pollock, Kenneth H., Scott R. Winterstein, and Michael J. Conroy. "Estimation and Analysis of Survival Distributions for Radio-Tagged Animals." Biometrics 45, no. 1 (March 1989): 99. http://dx.doi.org/10.2307/2532037.

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Pollock, Kenneth H., Christine M. Bunck, Scott R. Winterstein, and Chiu-Lan Chen. "A capture-recapture survival analysis model for radio-tagged animals." Journal of Applied Statistics 22, no. 5-6 (November 1995): 661–72. http://dx.doi.org/10.1080/02664769524522.

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Mcleod, M., and D. Goldney. "Home Range, Burrow Usage and Diel Activity of Platypuses on the Duckmaloi Weir, New South Wales." Australian Mammalogy 20, no. 2 (1998): 308. http://dx.doi.org/10.1071/am98319.

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Platypuses, Ornithorhynchus anatinus, have been studied on the Duckmaloi River, New South Wales, in a long term mark-release-recapture project from 1986 to 1996. Some animals are recaptured regularly, while others are trapped only once. A high percentage of juveniles are never retrapped. New animals continue to be captured each year. Hence radio-tracking was employed to examine the movements of animals within the river system including their spatial utilisation of the Duckmaloi Weir. Concurrent studies on activity patterns and burrow usage were undertaken. Seventeen animals (I 0 juveniles, 2 subadults and 5 adults) were radio-tracked for various lengths of time between January and October 1993. Telemetric data revealed that radio-tagged animals were not recaptured on all possible occasions. Home ranges (length of river) varied from 0.5 km to 3.5 km. Home ranges of all animals, overlapped extensively, while core area overlap also occurred in the pool behind the Duckmaloi weir. One juvenile male dispersed 8.5 km upstream from the weir. Platypuses typically utilised areas when feeding with water depth between I to 2.5 m, rarely using areas less than 0.5 m deep. Juvenile platypuses were crepuscular and nocturnal, while adults, although mainly nocturnal also exhibited individual variations in diurnality. Although some individuals remained active throughout the night, others returned to burrows before re-entering the water. Animals commonly returned to certain burrow complexes with some exhibiting a higher degree of burrow site specificity than others. Certain burrows were used by nearly all radio-tagged animals over time while others were used by only a select number of individuals. Some animals tracked in the weir pool were found to share burrows.

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Nams, Vilis O. "A technique to determine the behavior of a radio-tagged animal." Canadian Journal of Zoology 67, no. 2 (February 1, 1989): 254–58. http://dx.doi.org/10.1139/z89-036.

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I describe a technique to differentiate between activities of radio-tagged animals solely from radio signals. Signal amplitude and pulse interval data are transformed with time series analysis, and variables measured from the transformation are classified with discriminant function analysis. An example is given with known reference radio signals for three behaviors from striped skunks (Mephitis mephitis) in which 75% of the reference signals are classified correctly. If the classification is adjusted to allow for unclassifiable signals, then 23% are unclassifiable, but of the remaining 77%, 84% are classified correctly.

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Saunders, Debbie, Huyen Nguyen, Saul Cowen, Michael Magrath, Karen Marsh, Sarah Bell, and Josh Bobruk. "Radio-tracking wildlife with drones: a viewshed analysis quantifying survey coverage across diverse landscapes." Wildlife Research 49, no. 1 (February 4, 2022): 1–10. http://dx.doi.org/10.1071/wr21033.

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Radio-tracking tagged wildlife remains a critical research technique for understanding the movements, behaviours and survival of many species. However, traditional hand-held tracking techniques on the ground are labour intensive and time consuming. Therefore, researchers are increasingly seeking new technologies to address these challenges, including drone radio-tracking receivers. Following the implementation of drone radio-tracking techniques for five different threatened species projects within different habitat and landscape types, we identified the need to quantify the relative spatial extent of surveys using both drone and hand-held techniques for each project. This was undertaken using viewshed analyses. These analyses demonstrated that survey coverage with drone-based radio-tracking was substantially greater than that of hand-held radio-tracking for all species and landscapes examined. Within mountainous landscapes, drone radio-tracking covered up to four times the area of hand-held tracking, whereas in flat to undulating landscapes, drone surveys covered up to 11.3 times the area that could be surveyed using hand-held techniques from the same locations on the ground. The viewshed analyses were also found to be a valuable visualisation tool for identifying areas for targeted surveys to reduce the risk of ‘losing’ tagged animals, which has traditionally been one of the biggest radio-tracking challenges.

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Lu, Jun, Huidong Li, Chuan Tian, Mitchell J. Myjak, Jie Xiao, Brian J. Bellgraph, Samuel S. Cartmell, and Zhiqun Daniel Deng. "A Frequency-Programmable Miniaturized Radio Frequency Transmitter for Animal Tracking." Sensors 21, no. 19 (October 8, 2021): 6683. http://dx.doi.org/10.3390/s21196683.

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In animal tracking applications, smaller transmitters can reduce the impact of the transmitter on the tagged animal and thus provide more accurate data about animal behavior. By combining a novel circuit design and a newly developed micro-battery, we developed frequency-programmable and more powerful radio frequency transmitters that are about 40% smaller and lighter in weight than the smallest commercial counterpart for animal monitoring at the time of development. The new radio frequency transmitter has a miniaturized form factor for studying small animals. Designs of two coding schemes were developed: one transmits unmodulated signals (weight: 152 mg; dimensions: Ø 2.95 mm × 11.22 mm), and the other transmits modulated signals (weight: 160 mg; dimensions: Ø 2.95 mm × 11.85 mm). To accommodate different transmitter life requirements, each design can be configured to transmit in high or low signal strength. Prototypes of these transmitters were evaluated in the laboratory and exhibited comparable or longer service life and higher signal strength compared to their smallest commercial counterparts.

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Ripperger, Simon P., Niklas Duda, Alexander Kölpin, and Gerald G. Carter. "Simultaneous Monitoring of the Same Animals with PIT Tags and Sensor Nodes Causes No System Interference." Animal Behavior and Cognition 7, no. 4 (November 1, 2020): 531–36. http://dx.doi.org/10.26451/abc.07.04.05.2020.

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Recent technological advances have multiplied the variety of biologgers used in wildlife research, particularly with small-bodied animals. Passive integrated transponders (PIT) have been used for decades to log visits of tagged animals at reader-equipped artificial feeders or roost boxes. More recently, novel miniaturized sensor nodes can collect data on social encounters among tagged individuals in any location. Combining these systems allows researchers to gather high-resolution tracking data on certain individuals from their long-term PIT-tagged animal populations. However, there can be a risk of interference among tracking systems. Here we tested whether placing an additional biologging sensor on top of a PIT tag might attenuate the magnetic field reaching the PIT tag and, in turn, hamper reading success of the radio-frequency identification (RFID) reader. We also evaluated data transmission by a digital sensor node in the presence of a magnetic field created by the RFID antenna. The combination of this RFID system and wireless biologging sensors works without error, suggesting that the simultaneous use of PIT tags and other digital biologgers, e.g., miniaturized GPS-loggers, should also work together properly when communication channels do not overlap. The combination of long-term monitoring with PIT tags and short-term tracking with biologging sensor nodes creates exciting new opportunities to gather rich social data when individuals are not present at RFID reader stations.

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Skogland, Terje. "Movements of tagged and radio-instrumented wild reindeer in relation to habitat alteration in the Snøhetta region, Norway." Rangifer 6, no. 2 (June 1, 1986): 267. http://dx.doi.org/10.7557/2.6.2.658.

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In winter, 1981, 103 reindeer, out of a population of 3600, were herded into a fence by snowmobiles and marked. During the next 4 1/2 years reindeer were followed from the ground, or by radiolocations from an airplane. On the average one animal was tagged per 42 animals in any group. A total sample of 175 locations in all seasons indicated that snow conditions, traffic on a road lying parallel to a railroad, and the damming of a lake significantly affected annual distribution as compared with expected modern as well as prehistoric distribution.

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Cowan, PE, RE Brockie, GD Ward, and MG Efford. "Long-distance movments of juvenile brushtail possums (Trichosurus vulpecula) on farmland, Hawkes Bay, New Zealand." Wildlife Research 23, no. 2 (1996): 237. http://dx.doi.org/10.1071/wr9960237.

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Long-distance movements of juvenile male and female brushtail possums (Trichosurus vulpecula) at a farmland site, Hawke's Bay, New Zealand, were studied by radio-tracking. About 20% of radio-tagged possums dispersed more than 2 km, moving up to 11.5 km from their natal area, most in a north-easterly direction. The proportion of males that dispersed was higher than that of females, but the difference was not statistically significant. All juveniles dispersing did so before they were one year old. The bimodal timing of dispersal in summer and late winter to early spring reflected an underlying similar pattern of breeding. Most possums made several moves before settling. A higher proportion of possums dispersed from the lowdensity area of pastoral and cropping land than from the higher-density areas of swamp and willows. A few dispersal records of ear-tagged animals were also obtained; most records were of males from the area of pastoral and cropping land, and movements ranged from 3 to 25 km.

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Cliff, Oliver M., Debra L. Saunders, and Robert Fitch. "Robotic ecology: Tracking small dynamic animals with an autonomous aerial vehicle." Science Robotics 3, no. 23 (October 17, 2018): eaat8409. http://dx.doi.org/10.1126/scirobotics.aat8409.

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Understanding animal movements that underpin ecosystem processes is fundamental to ecology. Recent advances in animal tags have increased the ability to remotely locate larger species; however, this technology is not suitable for up to 70% of the world’s bird and mammal species. The most widespread technique for tracking small animals is to manually locate low-power radio transmitters from the ground with handheld equipment. Despite this labor-intensive technique being used for decades, efforts to reduce or automate this process have had limited success. Here, we present an approach for tracking small radio-tagged animals by using an autonomous and lightweight aerial robot. We present experimental results where we used the robot to locate critically endangered swift parrots (Lathamus discolor) within their winter range. The system combines a miniaturized sensor with newly developed estimation algorithms to yield unambiguous bearing- and range-based measurements with associated measures of uncertainty. We incorporated these measurements into Bayesian data fusion and information-based planning algorithms to control the position of the robot as it collected data. We report estimated positions that lie within about 50 meters of the true positions of the birds on average, which are sufficiently accurate for recapture or observation. Further, in comparison with experienced human trackers from locations where the signal was detectable, the robot produced a correct estimate as fast or faster than the human. These results provide validation of robotic systems for wildlife radio telemetry and suggest a way for widespread use as human-assistive or autonomous devices.

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Thiem, Jason D., Brendan C. Ebner, and Rhian C. Clear. "Validating variation in radio-signal strength as an index of aquatic fauna activity." Australian Journal of Zoology 58, no. 1 (2010): 50. http://dx.doi.org/10.1071/zo09110.

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Studying biological rhythms of activity and determining the external factors that influence behaviour of animals can be challenging in many aquatic habitats. We investigated the validity of using variations in radio-signal strength to quantify changes in activity of radio-tagged aquatic fauna on a small spatial scale under controlled conditions in the field. We monitored short-term activity (<1 min) of two aquatic species, rainbow trout (Oncorhynchus mykiss) and Murray River crayfish (Euastacus armatus), that differ markedly in their primary mode of movement. Simultaneous video monitoring confirmed that active and inactive periods for both species could be accurately determined by radio-telemetry, as were specific behaviours exhibited by trout. We were also able to quantify activity based on different radio-tag (coil and trailing whip antennas) and receiving antenna configurations (yagi and gap-loop antennas); however, we recommend use of control tags to provide reference data. Variation in radio-signal strength represents a valid means of monitoring activity of moderately site-attached aquatic species.

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Nguyen, Hoa Van, Michael Chesser, Lian Pin Koh, S. Hamid Rezatofighi, and Damith C. Ranasinghe. "TrackerBots: Autonomous unmanned aerial vehicle for real‐time localization and tracking of multiple radio‐tagged animals." Journal of Field Robotics 36, no. 3 (January 4, 2019): 617–35. http://dx.doi.org/10.1002/rob.21857.

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Baumgartner, Mark F., and Bruce R. Mate. "Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 3 (March 1, 2005): 527–43. http://dx.doi.org/10.1139/f04-238.

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Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 19891991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 19891991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.

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Figueira, C. J. M., J. S. R. Pires, A. Andriolo, M. J. R. P. Costa, and J. M. B. Duarte. "Marsh deer (Blastocerus Dichotomus) reintroduction in the Jataí Ecological Station (Luís Antônio, SP): spatial preferences." Brazilian Journal of Biology 65, no. 2 (May 2005): 263–70. http://dx.doi.org/10.1590/s1519-69842005000200009.

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Throughout the latter half of the twentieth century, wildlife habitat destruction and species extinctions have greatly increased. As the number of endangered species grows, the use of reintroduction as a conservation tool against species extinction increases. This study focuses on a 16-month study on marsh deer reintroduced in the Jataí Ecological Station. The animals were radio tagged and tracked daily between December 1998 and April 2000. Displacement activity and spatial preferences were monitored by triangulation. The animals wandered the floodplains inside the protected area and also a floodplain that is part of privately owned property on the western edge of the Jataí Ecological Station. During the study, most of the reintroduced marsh deer preferred the private floodplain area more than the floodplains inside the protected area. This preference revealed the ecological importance of the area and the necessity of its incorporation into the Jataí Ecological Station.

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Green, David M., and Katharine T. Yagi. "Ready for bed: pre-hibernation movements and habitat use by Fowler’s Toads (Anaxyrus fowleri)." Canadian Field-Naturalist 132, no. 1 (August 28, 2018): 46–52. http://dx.doi.org/10.22621/cfn.v132i1.2023.

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We used radio-tracking to investigate movement patterns and habitat use of Fowler’s Toads (Anaxyrus fowleri) during late summer and early fall in a relatively undisturbed lakeshore dune and beach habitat at Long Point, Ontario. Small radio transmitters were fitted to 11 adult toads with an external harness made from fine surgical plastic tubing wrapped around the body behind the front limbs. We located radio-tagged toads morning and evening, for a maximum of 9 days, recording their locations using Global Positioning System units. Initially, the toads were located on the upper beach or in the fore-dunes during the day, either dug in under the sand or hiding beneath debris; in the evening, they were generally active on the lower beach close to the water line. After a storm and the onset of cooler autumn weather, the toads tended to move further from the water line. They also curtailed their nightly activity and retreated deeper into the sand. As this sort of behaviour was not observed during the summer, we interpret it as pre-hibernation movement to more stable sites away from the beach where the animals can burrow deeply into the sand to lie dormant during the winter.

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Jackson, George D., Ron K. O'Dor, and Yanko Andrade. "First tests of hybrid acoustic/archival tags on squid and cuttlefish." Marine and Freshwater Research 56, no. 4 (2005): 425. http://dx.doi.org/10.1071/mf04248.

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This study demonstrates the simultaneous use of acoustic and archival tags for obtaining data for near-shore species. Australian giant cuttlefish Sepia apama (off Whyalla, South Australia) and the tropical squid Sepioteuthis lessoniana (off Magnetic Island, Queensland, Australia) were tagged using a ‘hybrid’ tag consisting of a Vemco V8 acoustic tag potted with a Vemco minilog temperature–depth archival tag. Four of these animals were released and monitored inside radio-acoustic-positioning-telemetry (RAPT) buoy-system arrays that included bottom-mounted sensors that transmitted independent temperature records and a reference standard for sound conductivity and position. All were subsequently located out of RAPT range and two of the four archival tags were recovered. Tags were located using a boat-mounted hydrophone and VR60 receiver and recovery was aided by a diver operating a hand-held VUR96 receiver. This technology provides a cost-effective alternative to expensive satellite pop-up tags and is suitable for much smaller species that return to near-shore environments.

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Sandberg, Jacqueline E., Timothy R. Van deelen, and Mark E. Berres. "Survival of rehabilitated and released red-tailed hawks (Buteo jamaicensis)." Wildlife Rehabilitation Bulletin 38, no. 1 (January 25, 2022): 28–39. http://dx.doi.org/10.53607/wrb.v38.177.

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Wildlife rehabilitation provides responsible care for sick, injured or orphaned wild animals with the goal of releasing fully recovered individuals back into the environment. Post-release survival data for these animals remain sparse but necessary to measure and assess the impact of wildlife rehabilitation as a conservation strategy. This study used national banding data to quantitatively compare annual survival of wild-caught (non-rehabilitated) and rehabilitated red-tailed hawks (Buteo jamaicensis). In addition, 13 rehabilitated and released red-tailed hawks from Dane County Humane Society’s Wildlife Center (DCHS, Madison, WI) were monitored using radio telemetry. Annual survival of rehabilitated and radio-tagged red-tailed hawks from DCHS was 36% over 85 weeks of monitoring. Nationally, wild red-tailed hawk annual survival (0.777; 95% CI [0.768, 0.777]) was largely equivalent to estimates reported in other published studies. These estimates reflect average survival over 40 years in a fully time-dependent model (variance component estimated using the Delta Method; Powell 2007). Rehabilitated red-tailed hawks had an annual survival of 0.549 (95% CI: 0.523, 0.575]) over 43 years. These values reflect model-averaged estimates from time-independent survival models (recovery was time dependent) that were equivalent in terms of likelihood (Brownie = Seber = wi = 0.50). Consequently, survival of rehabilitated red-tailed hawks was approximately 22% lower than wild-caught individuals. Furthermore, young (hatch-year) red-tailed hawks experienced increased mortality (34%) relative to those rehabilitated as adults (0.255; 95% CI [0.199, 0.321] versus 0.598; 95% CI [0.571, 0.624], respectfully). The results of this study demonstrate the need for additional post-release monitoring and may guide future management decisions regarding wildlife rehabilitative criteria, practice and viability.

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Melnychuk, Michael C., and Carl J. Walters. "Estimating detection probabilities of tagged fish migrating past fixed receiver stations using only local information." Canadian Journal of Fisheries and Aquatic Sciences 67, no. 4 (April 2010): 641–58. http://dx.doi.org/10.1139/f09-199.

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We developed a method to predict the probability of detecting acoustic tags crossing a receiver station using only detection information at that station. This method is suitable for acoustic or radio telemetry studies in which individually tagged animals migrate past fixed stations (where a station may consist of one or more receivers). It is based on fitting attenuation models to sequences of detections and missed transmissions of individually coded tags in fish migrating past stations of the Pacific Ocean Shelf Tracking Project (POST). We used estimated attenuation model parameters from detected fish at each station to predict the number of fish that crossed the station undetected, which in turn was used to calculate the local detection probability. This estimator was correlated (r = 0.54–0.81 in river and coastal habitats) with mark–recapture estimates of detection probability (pmr) that use nonlocal detection information at stations further along migration routes. This local detection probability estimate can be used as a covariate of pmr in mark–recapture models and can predict approximate values of pmr at final detection stations where pmr is not estimable because of the lack of recaptures further along migration routes.

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Carey, T. J., and C. J. Smallridge. "A Research Project to Establish Criteria for the Reintroduction of Platypuses (Ornithorhynchus anatinus Into Selected Locations in South Australia." Australian Mammalogy 20, no. 2 (1998): 300. http://dx.doi.org/10.1071/am98300.

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Platypuses were once common through many waterways of South Australia but now only live in a small system of rivers on Kangaroo Island where they were introduced in 1940. There is renewed interest from individuals and organisations in re-establishing the species in areas of mainland South Australia. The main objective of this project is to identify essential criteria for maintaining platypuses in South Australian ponds. Platypuses were captured on Kangaroo Island and introduced into a two pond system at McLaren Vale south of Adelaide. The animals were radio tagged and their behaviour monitored. Prior to introduction the habitat was fenced to exclude foxes and feral cats. The ponds were improved by the removal of mosquito fish and trout, placement of snags in the water, planting of aquatic vegetation at the margin and management of the water volume and surface area. Observations indicated that soft moist soil at water level aids the creation of burrows and refuges which may take months to establish. In the interim platypuses will make use of natural earth cracks or create refuges in vegetation. The animals are active in the grassy surrounds, move freely between ponds and feed on supplements of mealworms and earthworms. Key requirements for establishing platypuses in pond systems will include the exclusion of mammalian predators, providing a habitat conducive to the establishment of burrows and optimising food availability.

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Thiem, J. D., D. Hatin, P. Dumont, G. Van Der Kraak, and S. J. Cooke. "Biology of lake sturgeon (Acipenser fulvescens) spawning below a dam on the Richelieu River, Quebec: behaviour, egg deposition, and endocrinology." Canadian Journal of Zoology 91, no. 3 (March 2013): 175–86. http://dx.doi.org/10.1139/cjz-2012-0298.

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Knowledge of the reproductive biology of wild sturgeon populations is critical to ensure the survival of this unique group of animals. We combined gill-netting surveys, nonlethal blood sampling, radiotelemetry, and egg collection to examine the reproductive biology of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) at a suspected spawning ground below a dam on the Richelieu River, Quebec. Lake sturgeon were present at the beginning of sampling in early May, and spawning took place from 26 May to 5 June when water temperature averaged 13.4 ± 0.1 °C (range 11.5–15.5 °C). Daily spawning population estimates ranged from 285 to 1282 individuals and the sex ratio of spawners was estimated at 2.1 males per female. The presence of radio-tagged individuals on the spawning grounds peaked from 20 to 28 May, corresponding with known spawning bouts. Residence time of spawners on the spawning ground ranged from 1 to 27 days (median = 5 days) and there were no differences in residence time between sexes. Nonlethal blood sampling enabled the quantification of steroid levels to determine the spawning population sex ratio, and steroid levels were highest before spawning was known to occur and decreased concurrently with, and after, known spawning events.

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Coman, BJ, J. Robinson, and C. Beaumont. "Home Range, Dispersal and Density of Red Foxes (Vulpes Vulpes L.) In Central Victoria." Wildlife Research 18, no. 2 (1991): 215. http://dx.doi.org/10.1071/wr9910215.

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Between 1983 and 1986, various aspects of red fox spatial behaviour were studied in both rural and semi-urban environments in central Victoria. Using radio-telemetry, the short-term home ranges of three adult foxes (2 male, 1 female) in a pasture/woodland habitat were estimated to be of the order of 5-7 km2 each. In a semi-urban environment nearby, the home ranges of a further 3 adult animals (2 male, 1 female) were estimated to be 0.6-1.3 km2 each. Estimates of home range size based on a 90% space utilisation effectively halved the home range area for all six foxes. There were indications that, for the animals concerned, ranges were mutually exclusive except in the case of a breeding pair which shared a common home range. During the studies, 137 young fox cubs were ear-tagged and released at the point of capture. Subsequently, 46 of these animals were returned by hunters. Nearly 70% of the returned animals were killed at a distance of 2 km or less from the tagging site but dispersal distances of up to 30 km were recorded. The average dispersal distance for animals killed more than 2 km from the tagging site was 11 km. Estimates of fox density in a rural area of some 2400 ha were obtained by a survey of active breeding dens in the 1985 and 1986 breeding seasons. Assuming one breeding pair plus three surviving young per litter, the maximum summer density was estimated at about 3.0 foxes km-2 and the minimum winter density as about 1.2 foxes km-2. For a further estimate of density, 13 foxes were live-captured, fitted with radios and released. In a short control program on the study area a few weeks later, 7 of these animals were recovered in a total sample of 50 foxes killed. The remaining 6 foxes were established as still present in the study area. Using this capturehecapture data, an early autumn density of about 3.9 foxes km-2 was indicated. The significance of this data in relation to the possible role of foxes as vectors of rabies disease in Australia is discussed.

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Pilliod, David S., Charles R. Peterson, and Peter I. Ritson. "Seasonal migration of Columbia spotted frogs (Rana luteiventris) among complementary resources in a high mountain basin." Canadian Journal of Zoology 80, no. 11 (November 1, 2002): 1849–62. http://dx.doi.org/10.1139/z02-175.

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Information on how animals partition their activities and travel among complementary resources, such as breeding or overwintering habitats, is needed for species conservation. In a mountain basin at 2500 m elevation in central Idaho, we studied the habitat use and movement patterns of 736 marked and 87 radio-tagged Columbia spotted frogs (Rana luteiventris) from 1995 to 1998. The goals of this study were to (i) identify and characterize R. luteiventris breeding, summer foraging, and overwintering habitats, (ii) describe the movement patterns of juvenile, male, and female R. luteiventris among these resources, and (iii) determine migration routes. Juvenile and adult R. luteiventris occupied a variety of widely distributed wetlands from late June to September. On average, 132% of juvenile, 611% of male, and 1651% of female frogs moved from breeding ponds to summer habitats. Migratory males remained within 200 m of the breeding sites, whereas females traveled up to 1030 m to reach summer habitats. From late August through September, frogs migrated to deep (>3 m) lakes to overwinter. Frog migrations occurred quickly and often followed shortest-distance travel routes through dry, open forest even when stream corridors were available nearby. This study exemplifies the need to protect both complementary resources and the corridors connecting these anuran habitats.

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Johanna Rode, E., K. Anne-Isola Nekaris, Matthias Markolf, Susanne Schliehe-Diecks, Melanie Seiler, Ute Radespiel, and Christoph Schwitzer. "Social organisation of the northern giant mouse lemur Mirza zaza in Sahamalaza, north western Madagascar, inferred from nest group composition and genetic relatedness." Contributions to Zoology 82, no. 2 (May 6, 2013): 71–83. http://dx.doi.org/10.1163/18759866-08202001.

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Shelters such as leaf nests, tree holes or vegetation tangles play a crucial role in the life of many nocturnal mammals. While information about characteristics and availability of these resources may help in conservation planning, nest use gives an indication about a species’ social organisation. The northern giant mouse lemur (Mirza zaza) is threatened by habitat loss within its restricted range. Our aim was to examine nest site preferences of M. zaza and to explore the species’ social organisation by examining sleeping site aggregation size and genetic relatedness within and between such aggregations. In the Ankarafa Forest inside Sahamalaza – Iles Radama National Park, northwestern Madagascar, we radio-tagged five male and three female M. zaza and followed them for 2.5 months during the dry season. We identified sleeping trees and observed animals during emergence in the evening and return in the morning. We compared sleeping trees and microhabitats around nest sites to trees and habitat used during nightly activity and to random sites. We found that nests were well covered by canopy, even during the dry season, and were located near the tree trunk a few meters below the tree top. Nest sites were characterised by large (> 30 cm DBH) and tall trees (>16 m) with many lianas. Up to four animals shared one to three group-exclusive nests for up to 50 days. Two of the nest groups included two and three males with fully developed testes. Relatedness data revealed that the adult males sharing nests were either unrelated or closely related. These data suggest that M. zaza is sleeping in social nest groups including multiple males, which is unusual among nocturnal strepsirrhines. Apart from protecting suitable sleeping trees and discouraging selective logging of large trees, we recommend conducting further studies on the species’ social organisation throughout an entire season.

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FARFÁN, MIGUEL ÁNGEL, JESÚS DUARTE, JOHN E. FA, RAIMUNDO REAL, and JUAN MARIO VARGAS. "Testing for errors in estimating bird mortality rates at wind farms and power lines." Bird Conservation International 27, no. 3 (January 9, 2017): 431–39. http://dx.doi.org/10.1017/s0959270916000460.

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SummaryWind power, as an alternative to fossil fuels, is increasingly common, and is expanding worldwide. Wind farms cause mortality of flying animals through collision with moving rotor blades, and from electrocution on associated power lines. Avian mortality rates have been estimated from birds collected under turbines over varying time intervals. However, without adequate and frequent monitoring, dead birds may be removed by scavengers and thus cause an underestimation of fatalities. In this paper, we tested experimentally for possible errors arising in avian mortality caused by the removal of carcasses by scavengers. At two different wind farms and associated power lines in southern Spain, we placed pigeon and quail carcasses to determine their disappearance rate. All dead pigeons were radio-tagged to estimate distances taken by scavengers. We found significant differences in carcass disappearance rates of pigeons and quails, and between wind farms and power lines but not between habitats. All quails and 45% of pigeon carcasses had disappeared by the third and fourteenth day, respectively. Less than half (40%) of the carcasses were found < 100 m from where they were deposited. While scavenging losses may vary according to the location of the wind farm or power line, here we propose a method to estimate correctly the number of fatalities at any wind farm and power line. Using this method, we can improve our understanding of the real impact of wind structures on adjacent bird communities, and adopt appropriate measures to ensure their conservation.

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Cowled, Brendan D., Eddie Gifford, Michelle Smith, Linton Staples, and Steven J. Lapidge. "Efficacy of manufactured PIGOUT® baits for localised control of feral pigs in the semi-arid Queensland rangelands." Wildlife Research 33, no. 5 (2006): 427. http://dx.doi.org/10.1071/wr05083.

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Conservative population declines of 73% were recorded in three independent feral pig populations in Welford National Park, Queensland, when PIGOUT® baits containing 72 mg of sodium fluoroacetate were used in a baiting program following prefeeding. Declines were measured using a prebaiting population census with remote cameras, followed by carcass recovery. The knockdown of susceptible feral pigs may have been higher than this, since any carcasses not recovered reduced the recorded efficacy. In addition, feral pigs know to have left the baiting area after trapping and telemetry-tagging, and subsequently not exposed to toxic baits, were included in the analysis. The use of remote cameras and carcass recovery appears to be a relatively accurate means of recording localised declines in feral pig populations. This method is applicable only when carcass recovery is possible, such as in open areas in the semi-arid rangelands. A decline of 86% of radio-tagged feral pigs attending bait stations was also recorded. Camera observations revealed no non-target consumption of baits. Measurement of sodium fluoroacetate–contaminated tissues from feral pigs showed that residues were too low to present a significant risk to recorded scavenging animals in the area. Some feral pigs vomited before death, with vomitus containing sodium fluoroacetate poison at high concentrations. No vomitus was consumed by non-target species. Almost all feral pigs were killed relatively rapidly after ingestion of sodium fluoroacetate and the signs observed in a small number of poisoned feral pigs did not indicate a significant welfare concern.

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Hagen, Chloe S., Laura L. Greiner, Dalton C. Humphrey, Gregory Krahn, and Joel Spencer. "161 The Impact of Sex, Birth Weight, and Nutrient Density on the Growth Restriction and Compensatory Gain of Finishing Hogs After a Three- or Six-Week Period of Nutrient Restriction." Journal of Animal Science 100, Supplement_2 (April 12, 2022): 77. http://dx.doi.org/10.1093/jas/skac064.124.

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Abstract The objective of this analysis was to investigate the effect of pig phenotype on growth restriction and compensatory ability after receiving a nutrient-deficient (97% corn) diet for 3 or 6 weeks. Sixteen hundred and sixty mixed-sex pigs (DNA Genetics, Columbus, NE) were tagged with radio frequency identification tags (LeeO, Prairie Systems, Spencer, IA) at birth with litter information and body weight (BW) measured at birth, weaning, and the end of the nursery phase. At a starting BW of 73.5 ± 2.2 kg, pigs were blocked by BW to 140 pens and assigned to a 2:3:1 factorial. The seven treatments were comprised of a combination of 2 restriction lengths (3 weeks vs. 6 weeks) and 3 lysine inclusion levels at re-alimentation (Lys:ME of 100%, 110%, or 120% of the genetic margin over feed curve), and a control that remained nutrient unrestricted. Individual BW was measured on trial d 0, 21, 41, and market to calculate individual average daily gain (ADG) for each phase. Percent change in ADG between each phase was calculated using the previous ADG of each pig. Observational analysis was conducted in SAS 9.4 (Cary, NC) with pig as the observational unit. When fed the restrictive diet, gilts had a greater reduction in ADG (P < 0.01) than barrows (64 vs. 59 % decrease in ADG from previous period). Furthermore, pigs with lower birth weight, thus lighter starting trial weight, had a greater decrease (P < 0.01) in growth in response to nutrient restriction. Validating the biological requirements of finishing pigs, animals with a greater lysine requirement, gilts, and lighter weight pigs had a more severe reduction in growth than those with a decreased lysine requirement.

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Meek, PD. "A biological review of Pseudomys oralis: a response to Pyke and Read." Australian Mammalogy 25, no. 2 (2003): 209. http://dx.doi.org/10.1071/am03209.

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IN their recent paper, Pyke and Read (2002) provide a detailed review of the biology and ecology of the Hastings River mouse Pseudomys oralis. The authors should be commended for compiling this information, however, there are some comments I would like to make to provide a contemporary review of this species. The authors note there has been no discussion of geographic variation within P. oralis or recognition of a subspecies. However, the recovery plan (NPWS 2003), which has been in draft for many years, emphasises the need to survey populations between the mitochondrial DNA haplotype sites identified by Jerry et al. 1998 to determine whether there are two distinct species. Pyke and Read (2002) also maintain the historical belief that P. oralis is mostly found in open habitat associated with riparian features (gullies and watercourses). Based on the studies of Townley (2000), Keating (2000) and new data collected by Meek (2002) and Meek et al. (2003), there is evidence that P. oralis is not dependent on riparian habitat. The species has been captured at many ridge and mid-slope sites where sedges and/or grasses are not found in high abundance. High numbers of P. oralis trapped and monitored at Marengo State Forest since 2000 have been found living on a ridge top in an open forest habitat dominated by fern (Meek 2002; Meek et al. 2003). Radio tracking and spool-and-line tracking from this forest showed that P. oralis did not favour a microhabitat of grasses or sedges and when riparian habitat was available the tagged animals rarely used it. Habitat at known P. oralis sites indicate that shelter is an important factor in population size, however emphasising the value of rock shelter as an indicator of capture success (Keating 2000) ignores the value of head and butt residue and fallen timber for the species. In all of the trapping sites described in Meek et al. (2003), none contained large amounts of large or small rock. However, occurrence of the species and trap success does correspond with the amount of hollows in fallen timber and residues from previous logging events and is further supported by tracking observations (Meek 2002, 2003).

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Woolnough, Andrew P., Tim J. Lowe, and Ken Rose. "Can the Judas technique be applied to pest birds?" Wildlife Research 33, no. 6 (2006): 449. http://dx.doi.org/10.1071/wr06009.

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The Judas technique was evaluated for its use as a technique to assist with the control of the common starling (Sturnus vulgaris). This technique uses the natural behaviour of a gregarious animal to betray the location of itself and its companions through radio-telemetry. Two trials were conducted to assess and develop the technique for starlings. The first trial was conducted near the western edge of the starling’s current established range in Australia, at Penong in South Australia. Nine out of ten radio-tagged birds were successfully tracked from the ground and air. Estimates of the areas utilised varied from 1.1 km2 to 96.5 km2 (100% convex polygons). Night-time roosts were found for three of the nine radio-tagged birds and control (shooting) recovered just one bird directly associated with a Judas starling, as well as the radio-tagged bird. The second trial was conducted at Munglinup near Esperance in Western Australia. Munglinup is the site of a recent infestation of starlings and is the most western-known outlier of this pest in Australia. At this site, five radio-tagged starlings tracked from the ground and air, utilised areas ranging from 0.7 km2 to 51.6 km2. Reduced fidelity to roosting trees impaired our ability to destroy starlings here. However, the real value of the Munglinup trial was to expand the geographical area known to be occupied by this population from 103 km2 to more than 225 km2 and to identify habitats and roost sites used by the starlings. We conclude that the Judas technique could be applied to starlings and other pest birds with similar social structures as a means of strategic surveillance rather than as an adjunct to control per se.

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Fischer, C., and R. Tagand. "Spatial behaviour and survival of translocated wild brown hares." Animal Biodiversity and Conservation 35, no. 2 (December 2012): 189–96. http://dx.doi.org/10.32800/abc.2012.35.0189.

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The fragility of many populations of brown hares in Western Europe is a concern for managers, hunters and naturalists. We took advantage of a locally high density population to use wild individuals to restock areas where the species had disappeared or was close to disappearing. The aim of the project was to assess the evolution of the spatial behaviour after release using radio–tracking. Over 150 wild brown hares were translocated, one third of which were fitted with radio collars. In addition, fifteen individuals were radio–tagged and released back into the source population as a control. Most individuals settled in less than two months and their seasonal home range, once settled, was similar to that observed in the source population. Mean duration of tracking was not significantly different between the two groups. Moreover, two years after the last translocation, tagged individuals can still be observed, but most hares present are not tagged, which indicates natural reproduction of the released individuals. The translocation of wild individuals thus appears to give encouraging results.

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RÄTTI, Osmo, and Pirkko SKAMÄKI. "Female Attraction Behaviour of Radio Tagged Polyterritorial Pied Flycatcher Males." Behaviour 127, no. 3-4 (1993): 279–88. http://dx.doi.org/10.1163/156853993x00065.

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AbstractPolygynous mating is costly for pied flycatcher (Ficedula hypoleuca) females. Thus, females have a good reason to attempt to avoid mating with already mated polyterritorial males. One cue to disclose a male's mating status is his behaviour. The behaviour of polyterritorial and unmated males was studied by radio tagging that allows accurate recording of male movements. While attracting a secondary female polyterritorial males spent significantly less time on the secondary territory than did unmated males on their single territory. Polyterritorial males also tended to have lower song rates. When a female appeared on the secondary territory of polyterritorial males, they increased the proportion of time spent there, and as a result the difference between polyterritorial and unmated males was not significant. A female might potentially be able to estimate a male's mating status on basis of male presence at the territory, but only if she does not reveal herself. Still, the variation and overlap in male behaviour between mating categories may make it difficult for her to obtain reliable information about the mating status of a male.

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Law, B., M. Chidel, and A. Mong. "Life under a sandstone overhang: the ecology of the eastern cave bat Vespadelus troughtoni in northern New South Wales." Australian Mammalogy 27, no. 2 (2005): 137. http://dx.doi.org/10.1071/am05137.

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We studied the eastern cave bat (Vespadelus troughtoni) in northern New South Wales to provide ecological information on roosts and foraging. Radio-tracking of five bats was supplemented with opportunistic visits to roosts over five years. One male was radio-tracked and its roost was within a corrugated iron roof cavity of a dairy. Maternity roosts were located in the overhangs of large sandstone caves usually containing a dome at the rear. Searches of nearby cliff-lines found that small caves, crevices and overhangs were not used as day-roosts. Nor did any radio-tagged bat roost in tree hollows. Colony size of one tight roosting cluster was estimated as 240 individuals. Radio-tagged bats frequently switched roosts, while opportunistic visits over a five-year period often found caves unoccupied. Most movements between roosts were within 1.5 km, although one female moved about 3.75 km between roosts. One radiotagged female shifted roost to beneath the corrugated iron of a farm-shed that supported at least 50 bats, predominantly females with young. Observations of foraging radio-tagged and lighttagged bats were frequent along a stream lined with trees, but surrounded by cleared paddocks. Foraging was observed in the air space above the creek, interspersed with occasional rapid flights across paddocks (> 500 m). We suggest that a key requirement for V. troughtoni in the rural landscape is the presence of native vegetation in close proximity to roosts, although extensive forested areas may not be required. Education of local communities about the sensitivity of these bats at cave roosts would be an important contribution to their conservation.

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WALLS, S. S., and R. E. KENWARD. "Movements of radio-tagged Buzzards Buteo buteo in early life." Ibis 140, no. 4 (June 28, 2008): 561–68. http://dx.doi.org/10.1111/j.1474-919x.1998.tb04700.x.

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Ward, Richard M. P., and Charles J. Krebs. "Behavioural responses of lynx to declining snowshoe hare abundance." Canadian Journal of Zoology 63, no. 12 (December 1, 1985): 2817–24. http://dx.doi.org/10.1139/z85-421.

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The behavioural responses of lynx (Lynx canadensis) to declines in snowshoe hare (Lepus americanus) abundance were examined in the southwestern Yukon. Between April 1982 and June 1984, 11 lynx were radio tagged and monitored in and near the Kluane Game Sanctuary. Lynx home range size increased from 13.2 to 39.2 km2 concurrent with a decline in snowshoe hare abundance from 14.7 to 0.2 hares/ha. Below about 0.5 hares/ha, several lynx abandoned their home ranges and became nomadic, although they remained within the general study area. Lynx concentrated their foraging efforts in areas of relatively high snowshoe hare abundance and abandoned these areas after hares declined. Straight-line daily travel distance remained constant at 2.2−2.7 km/day above 1.0 hare/ha. Below 1.0 hares/ha, straight-line daily travel distances increased rapidly, reaching 5.5 km/day at 0.2 hares/ha. Three of seven radio-tagged lynx dispersed 250 km or more from the study area during the 1982 period of rapid hare decline. No similar long-distance emigrations were recorded after hare densities stabilized at less than 1.0 hares/ha. Trapping mortality was responsible for the loss of seven of nine radio-tagged lynx that travelled outside the game sanctuary. One lynx probably starved during the winter or spring of 1984. The high rate of trapping mortality outside the game sanctuary suggests that refugia in wilderness areas are important in maintaining lynx populations during periods of low recruitment.

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Walls, Sean S., Santi Manosa, Robin M. Fuller, Kathy H. Hodder, and Robert E. Kenward. "Is Early Dispersal Enterprise or Exile? Evidence from Radio-Tagged Buzzards." Journal of Avian Biology 30, no. 4 (December 1999): 407. http://dx.doi.org/10.2307/3677013.

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JOHNSON, OSCAR W., COREY D. ADLER, LEE ANNE AYRES, MARY ANNE BISHOP, JODI E. DOSTER, PATRICIA M. JOHNSON, RONALD J. KIENHOLZ, and SUSAN E. SAVAGE. "RADIO-TAGGED PACIFIC GOLDEN-PLOVERS: FURTHER INSIGHT CONCERNING THE HAWAII-ALASKA MIGRATORY LINK." Wilson Bulletin 116, no. 2 (June 2004): 158–62. http://dx.doi.org/10.1676/03-120.

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36

Naguib, Marc, Rainer Altenkamp, and Benjamin Griessmann. "Nightingales in space: song and extra-territorial forays of radio tagged song birds." Journal of Ornithology 142, no. 3 (July 2001): 306–12. http://dx.doi.org/10.1007/bf01651369.

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37

Tidemann, CR, DM Priddel, JE Nelson, and JD Pettigrew. "Foraging Behaviour of the Australian Ghost Bat, Macroderma gigas (Microchiroptera: Megadermatidae)." Australian Journal of Zoology 33, no. 5 (1985): 705. http://dx.doi.org/10.1071/zo9850705.

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The foraging behaviour of Macroderma gigas was investigated in the field by radio-tracking of tagged individuals and by direct observation of feeding bats in May 1983. Foraging areas were centred, on average, 1.9 km from the day roost. The mean size of foraging areas was 61 ha and tagged bats generally returned to the same areas each night. Hunting behaviour of bats within foraging areas consisted of observation at vantage points, with brief sallies to capture prey, mostly insects on the ground, although hawking of flying insects was also observed. Vantage points were changed about every 15 min during foraging periods. The mean distance between them was 360 m. Foraging areas were not exclusive, there was overlap between the ranges of several tagged individuals, and in one case an area was used by 20 bats.

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Capitolo, Phillip J., Lynn J. Jesus, Alan B. Harper, Allen M. Fish, and Angus C. Hull. "Fall migration of radio-tagged Broad-winged Hawks (Buteo platypterus) in California." Wilson Journal of Ornithology 132, no. 1 (July 22, 2020): 15. http://dx.doi.org/10.1676/1559-4491-132.1.15.

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39

Cederlund, Göran, Roger Bergström, and Finn Sandegren. "Winter activity patterns of females in two moose populations." Canadian Journal of Zoology 67, no. 6 (June 1, 1989): 1516–22. http://dx.doi.org/10.1139/z89-216.

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Data on activity patterns of nine radio-tagged female moose (Alces alces) in an area with a high level of nutrition (Grimsö) and seven radio-tagged female moose in an area with a low level of nutrition (Furudal) are presented. The study was done during January–May in 1982–1986 at Grimsö and in 1986 in Furudal, comprising 6063 and 4136 h of recording, respectively. The character of the radio signals allowed separation of active (any kind of body motion, mainly movements) and inactive (a motionless state, mainly in lying position) bouts. The 24-h activity pattern was similar between the two areas during all winter months. Active bouts showed a polyphasic pattern with prominent peaks around sunrise and sunset. The average active time per 24-h interval varied (30–50%) through the winter months, and increased rapidly in April and May. The average length of active bouts was similar in both areas during midwinter (60–70 min) but developed more rapidly in April and May among moose at Grimsö. The moose at Furudal rested for longer periods than those at Grimsö, and in both areas bouts became shorter towards spring (around 120 min). The moose at Grimsö kept the number of bouts per 24-h interval almost unchanged throughout winter (11.0–11.9), while the number consistently increased at Furudal (9.9–12.7 bouts per 24-h interval). Differences in activity pattern are discussed in relation to food availability and overbrowsing.

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Henkel, Laird A., Esther E. Burkett, and John Y. Takekawa. "At-sea Activity and Diving Behavior of a Radio-tagged Marbled Murrelet in Central California." Waterbirds 27, no. 1 (March 2004): 9–12. http://dx.doi.org/10.1675/1524-4695(2004)027[0009:aaadbo]2.0.co;2.

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Probst, Remo, Mihaela Pavličev, and Rudolf Schmid. "The Home Range and Notes on a Radio-tagged Northeastern Siberian Northern Goshawk (Accipitergentilis albidus)." Journal of Raptor Research 41, no. 4 (December 2007): 336–37. http://dx.doi.org/10.3356/0892-1016(2007)41[336:thrano]2.0.co;2.

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Hansen, H., C. A. Smedshaug, and G. A. Sonerud. "Preroosting behaviour of hooded crows (Corvus corone cornix)." Canadian Journal of Zoology 78, no. 10 (October 1, 2000): 1813–21. http://dx.doi.org/10.1139/z00-111.

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Gatherings of birds at preroosts before departure to nocturnal roosts have rarely been studied and their function is poorly understood. We recorded preroosting behaviour of hooded crows, Corvus corone cornix, in a mixed farmland-forest landscape in southeastern Norway during fall and winter, by selecting gatherings attended by at least one radio-tagged crow for observation. The preroosting crows perched in a highly aggregated and exposed group and did not forage. As the amount of snowfall during the preceding 24 h increased, an indication of sudden difficulty in finding food, the maximum number of crows that gathered increased, the duration of the gathering increased, and the straight-line distance covered by the radio-tagged crows from preroost to roost increased. The crows flew conspicuously in formation more often and for a longer time when on their way from preroost to roost on days with stronger winds. The results suggest that, in hooded crows, a preroost gathering is not simply a consequence of many individuals approaching the same roosting area but has some function, presumably that of maximizing the probability of finding rewarding food sites the next day by finding is a communal roost where information on the location of these sites may be obtained.

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TYACK, A. J., S. S. WALLS, and R. E. KENWARD. "Behaviour in the post-nestling dependence period of radio-tagged Common Buzzards Buteo buteo." Ibis 140, no. 1 (June 28, 2008): 58–63. http://dx.doi.org/10.1111/j.1474-919x.1998.tb04541.x.

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PROSSER, PHIL, SARA BROWN, and KATE BROOKES. "Does the presence of a human tracker affect the behaviour of radio-tagged wood mice Apodemus sylvaticus?" Mammal Review 34, no. 4 (December 2004): 311–14. http://dx.doi.org/10.1111/j.1365-2907.2004.00051.x.

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Law, B. S. "The Lunar Cycle Influences Time of Roost Departure in The Common Blossom Bat, Syconycteris australis." Australian Mammalogy 20, no. 1 (1998): 21. http://dx.doi.org/10.1071/am97021.

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Observations of radio-tagged Common Blossom Bats Syconycteris australis on the Atherton Tablelands, Queensland indicate that the time of departure from roost areas is related to the lunar cycle. During the dark phase of the moon, bats leave their roost between 5-20 mins after dark. Departure times are delayed up to 4 hrs between the period of the first quarter and full moon when the moon is bright after dusk. The predatory role of owls at night is suggested as the probable cause of this behavioural change.

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Vessem, Janine, and D. Draulans. "Spatial distribution and time budget of radio-tagged grey herons,Ardea cinerea, during the breeding season." Journal of Zoology 213, no. 3 (November 1987): 507–34. http://dx.doi.org/10.1111/j.1469-7998.1987.tb03723.x.

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Warkentin, Ian G. "Factors affecting roost departure and entry by wintering merlins." Canadian Journal of Zoology 64, no. 6 (June 1, 1986): 1317–19. http://dx.doi.org/10.1139/z86-195.

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Merlins (Falco columbarius) overwintering in Saskatoon, Saskatchewan, depended upon mature spruce trees, planted in residential areas of the city, for roosting sites. Variation in entry times at the roost by radio-tagged Merlins was accounted for by sunset time, total daily solar radiation, and temperature. To a lesser extent the variation in departure times was explained by sunrise time and temperature. Merlins left the roost significantly earlier as the days became shorter in the period leading up to the winter solstice, but returned at the same time relative to sunset resulting in a longer active phase than that provided by natural day length.

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Jones, Todd M., Jeffrey D. Brawn, and Michael P. Ward. "Development of activity rates in fledgling songbirds: when do young birds begin to behave like adults?" Behaviour 155, no. 5 (2018): 337–50. http://dx.doi.org/10.1163/1568539x-00003492.

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Abstract Logistical and technological limitations have constrained the characterization of behavioural development in songbirds, particularly during the post-fledging period. Recently, advances in radio-telemetry technology — automated radio-telemetry systems (ARTS) capable of recording continuous, high-resolution spatial-temporal data on radio-tagged birds — have opened the door to more comprehensive examinations of fledgling behaviour. We examined development of activity rates (number of times a bird was determined to have moved per number of detections, per hour) in fledgling Dickcissels using ARTS established at two grassland sites in east-central Illinois, USA. Specifically, we described general patterns of fledgling activity rates and determined the age at which fledglings began exhibiting activity rates like adults. We found that juveniles decreased activity rates immediately following fledging, likely to avoid detection by snakes and other predators, but increased activity levels throughout the rest of the post-fledging period. Peak hours of fledgling activity occurred around 0700 and 1800 h for all ages, with consistently low activity rates at night. On average, fledglings began exhibiting adult-like activity rates approximately 22 days after fledging, around roughly the same time they stopped being fed by adults. While our study provides important insights into development of fledgling behaviour in the Dickcissel, it remains unclear how patterns of behavioural development vary within and among species.

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Friend, J. Anthony, Robert Hill, Brian Macmahon, Louisa Bell, Tim Button, Corey Mosen, and Stephanie Hill. "Are red-tailed phascogales (Phascogale calura) at risk from Eradicat® cat baits?" Wildlife Research 47, no. 8 (2020): 747. http://dx.doi.org/10.1071/wr19087.

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Abstract ContextFeral cats have benefitted from effective control of foxes in south-western Australia and, consequently, their impact on some threatened mammal species has increased. Control of feral cats in the region can be enhanced by use of the Eradicat® cat bait, but its impact on non-target animal populations requires investigation before widespread use. AimsThe aim of the present study was to determine through field trials whether consumption of Eradicat® baits by resident red-tailed phascogales, following a broadscale baiting operation to control feral cats, was sufficiently frequent to cause significant rates of mortality in wild populations of phascogales. MethodsNine radio-tagged red-tailed phascogales were monitored through an Eradicat® baiting event to determine their survival. Removal and consumption of toxic and non-toxic rhodamine B-labelled baits by a range of species were monitored with camera traps and by subsequent trapping of red-tailed phascogales and other mammals to sample whiskers for evidence of rhodamine uptake. Key resultsAlthough some phascogales showed interest in baits and sometimes moved them from the deposition site, all radio-tagged phascogales survived for at least 1 week after baiting, by which time very few or no baits remained. Examination of whiskers sampled from individuals exposed to rhodamine-labelled baits showed that consumption of non-toxic Eradicat® baits by phascogales was negligible; only one phascogale of 62 sampled showed any rhodamine banding. ConclusionsThe present study provided no evidence that red-tailed phascogales in the study region are at risk from an Eradicat® baiting episode in autumn. ImplicationsThe risk to red-tailed phascogale populations through the use of Eradicat® baiting to control cats in their habitat in the Great Southern region of Western Australia is likely to be low. Further research to elucidate any impact of repeated baiting on populations of this species at several locations is recommended.

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VESSEM, JANIKE VAN, DIRK DRAULAKS, and ANTOON F. DE BONT. "Movements of radio-tagged Grey Herons Ardea cinerea during the breeding season in a large pond area." Ibis 126, no. 4 (April 3, 2008): 576–87. http://dx.doi.org/10.1111/j.1474-919x.1984.tb02081.x.

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Journal articles on the topic 'Radio-tagged animals'

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