Sensor:
Radio Transmitter

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Radio Transmitter
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radio-transmitter
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search.filters.applied.f.sensorName: Radio Transmitter × Subject: animal movement ×

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Now showing 1 - 10 of 17
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    Data from: Movements of neotropical understory passerines affected by anthropogenic forest edges in the Brazilian Atlantic Rainforest
    (2021-11-03) Hansbauer, Miriam M.; Storch, Ilse; Pimentel, Rafael G.; Metzger, Jean Paul; Leu, Stephan; Nieto-Holguin, Juan-Pablo
    Edge effects are suggested to have great impact on the persistence of species in fragmented landscapes. We tested edge avoidance by forest understory passerines in the Brazilian Atlantic Rainforest and also compared their mobility and movement patterns in contiguous and fragmented landscapes to assess whether movements would increase in the fragmented landscape. Between 2003 and 2005, 96 Chiroxiphia caudata, 38 Pyriglena leucoptera and 27 Sclerurus scansor were radio-tracked. The most strictly forest species C. caudata and S. scansor avoided forest edges, while P. leucoptera showed affinities for the edge. Both sensitive species showed larger mean step length and maximal observed daily distance in the fragmented forest versus the unfragmented forest. P. leucoptera did not show any significant difference. There were no significant differences in proportional daily home range use for any of the three species. Our results suggested that fragmentation and the consequent increase in edge areas do influence movement behavior of sensitive forest understory birds that avoided the use of edges and increased the speed and distance they covered daily. For the most restricted forest species, it would be advisable to protect larger patches of forest instead of many small or medium fragments connected by narrow corridors. However, by comparing our data with that obtained earlier, we concluded that movement behavior of resident birds differs from that of dispersing birds and might not allow to infer functional connectivity or landscape-scale sensitivity to fragmentation; a fact that should be taken into consideration when suggesting conservation strategies.
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    Data from: Spatial ecology of copperhead snakes (Agkistrodon contortrix) in response to urban park trails
    (2020-03-20) Carrasco-Harris, Malle F.; Cole, Judith A.; Reichling, Steve
    NOTE: An updated and larger version of this dataset is available. See https://doi.org/10.5441/001/1.1rs3j824. ABSTRACT: Urban forests and parks are important for recreation and may serve as a natural corridor for commuters. The consequences of human-mediated disturbance in natural areas are documented for avian and mammalian species. Less is known about the consequences of human disturbance on reptile species, specifically snakes, residing in natural refuges within the urban matrix. Thus, we examined the spatial activity of copperheads (Agkistrodon contortrix) in regard to pedestrian trails within an urban forest. We used radio telemetry to track snakes during the active season and estimated distances moved in between relocations, distances to the nearest trail and home range size for individuals. We found sex and season, but not distance to the nearest trail, affected the distance snakes moved. In addition, we observed a weak, positive relationship between home range size and average distance to the trail. Sex, season and body condition did not explain snake distance to the trail, but individual patterns were variable for snakes compared to random locations generated from snake relocations. Our study indicates copperheads may be tolerant of low-level human disturbances found in an urban forest. Further work should be done to quantify levels of disturbance, such as trail use, and compare the behavior of reptiles across urban park types and locations.
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    Data from: Modelling landscape connectivity for greater horseshoe bat using an empirical quantification of resistance
    (2018-07-09) Pinaud, David; Claireau, Fabien; Leuchtmann, Maxime; Kerbiriou, Christian
    (1) Habitat fragmentation and isolation as a result of human activities have been recognized as great threats to population viability. Evaluating landscape connectivity in order to identify and protect linkages has therefore become a key challenge in applied ecology and conservation. (2) One useful approach to evaluate connectivity is Least‐Cost Path (LCP) analysis. However, several studies have highlighted importance of parameterization with empirical, biologically‐relevant proxies of factors affecting movements, as well as the need to validate the LCP model with an independent dataset. (3) We used LCP analysis incorporating quantitative, empirical data about behaviour of the greater horseshoe bat Rhinolophus ferrumequinum to build up a model of functional connectivity in relation to landscape connecting features. We then validated the accumulated costs surface from the LCP model with two independent datasets; one at an individual level with radio tracking data and one at a population level with acoustic data. (4) When defining resistance, we found that the probability of bat presence in a hedgerow is higher when the distance between hedgerows is below 38 m, and decrease rapidly when gaps are larger than 50 m. The LCP model was validated by both datasets: the independent acoustic data showed that the probability of bat presence was significantly higher in areas with lower accumulated costs, and the radio tracking data showed that foraging was more likely in areas where accumulated costs were significantly lower. (5) Synthesis and applications. Through our modelling approach, we recommend a maximum of 38m (and no more than 50m) between connecting features around colonies of greater horseshoe bats. Our quantitative study highlights the value of this framework for conservation: results are directly applicable in the field and the framework can be applied to other species sensitive to habitat loss, including other bats. Provided that it is parameterized with empirical, biologically‐relevant data, this modelling approach can be used for restoring and evaluating green networks in agri‐environmental schemes and management plans.
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    Data from: Ámbito de hogar y actividad circadiana del ocelote (Leopardus pardalis) en la Isla de Barro Colorado, Panamá
    (2020-07-03) Moreno, Ricardo; Mares, Rafael; Aliaga-Rossel, Enzo; Kays, Roland
    Because ocelots (Leopardus pardalis) are elusive species in the wild, little is known of them. This study determines the home range and circadian activity of this feline in the Barro Colorado Island (BCI), Panama. This island has a wet tropical rainforest. Using wooden box traps and Tomahawk traps, between July 2001 and May 2004 15 ocelots were captured, and three other ocelots in 2009. Once captured, they were sedated and VHF collars were fitted, for the ones captured in 2009 we fitted GPS collars. Camera-traps were used to get additional information from individuals without collars and a more reliable data interpretation. The average home range of ocelots, obtained by radio-telemetry was 3.48 km2 (DE: 3.17) for males and 1.48 km2 (DE: 0.65) for females, although an adult male used an area of 9 km2. Males traveled on average 1.15 km per day and females 0.7 km. Through telemetry and camera traps, we found that ocelots were primarily nocturnal (Night = 63.2%; Day = 36.8%). Our results are similar to other studies; however, they suggest that BCI ocelots have smaller home ranges due to the high availability of food and also by the high density of females within the home ranges of males.
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    Data from: Are movements of day- and night-time passerine migrants as different as day and night?
    (2020-09-08) Michalik, Bianca; Brust, Vera; Hüppop, Ommo
    Even after decades of research, the migration of songbirds still holds numerous secrets. Distinct stopover and routing behavior of diurnally and nocturnally migrating songbirds has been stated in the 1960s, but empirical confirmation is yet lacking widely. We studied the behavior of individual diurnally migrating dunnocks and nocturnally migrating blackcaps by means of large‐scale automated radio‐telemetry. Birds were radio‐tagged during their stopover at the German North Sea coast. Our data indicate longer initial stopover duration in the diurnally migrating dunnocks, opposing the hypothesis of nocturnal migrants needing more time to recover due to their longer migratory flights. Nonetheless, dunnocks stopped over more often along their tracks as when compared to the nocturnally migrating blackcaps. Behavior en route did not differ as clearly between species challenging the general view of contrasting routings of diurnal and nocturnal migrants with regard to landscape and open water. Our results imply additional factors of relevance other than differences in species or daily migration timing per se. We discuss and highlight the need of detailed and individual based data to better understand stopover and routing behavior of songbirds in the environmental context.
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    Data from: Two subspecies of a songbird migrant optimise departure from a coastal stopover with regard to weather and the route lying ahead
    (2022-11-18) Brust, Vera; Schmaljohann, Heiko; Hüppop, Ommo
    Songbirds on migration spend a greater share of their travelling time at stopover sites in order to rest, recover and refuel compared to actively flying. In the German Bight of the North Sea, two subspecies of the northern wheatear split travelling routes, with Greenlandic/Icelandic breeders (subspecies leucorhoa) facing a long over-sea flight and Scandinavian breeding birds (subspecies oenanthe) travelling further roughly along the coast. We used automated radio-telemetry in spring to show that leucorhoa birds stayed significantly longer at a coastal stopover site and clearly selected for favourable weather, especially easterly winds, when resuming flights Conditions for departures of individuals from the subspecies oenanthe were less obvious. They were more likely to depart on nights with southerly winds, often along with rising air temperatures, while air pressure dropped. Individuals of subspecies leucorhoa thus wait for optimal flying conditions to resume for longer flights, while oenanthe birds, with shorter distances ahead, seem to optimise time by leaving the stopover site more quickly. Our dataset thus confirms that songbirds optimise stopover based on their (sub)species-specific migration patterns.
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    Data from: Large-range movements of neotropical orchid bees observed via radio telemetry
    (2020-07-03) Wikelski, Martin; Moxley, Jerry; Eaton-Mordas, Alexander; López-Uribe, Margarita M.; Holland, Richard A.; Moskowitz, David; Roubik, David W.; Kays, Roland
    Neotropical orchid bees (Euglossini) are often cited as classic examples of trapline-foragers with potentially extensive foraging ranges. If long-distance movements are habitual, rare plants in widely scattered locations may benefit from euglossine pollination services. Here we report the first successful use of micro radio telemetry to track the movement of an insect pollinator in a complex and forested environment. Our results indicate that individual male orchid bees (Exaerete frontalis) habitually use large rainforest areas (at least 42–115 ha) on a daily basis. Aerial telemetry located individuals up to 5 km away from their core areas, and bees were often stationary, for variable periods, between flights to successive localities. These data suggest a higher degree of site fidelity than what may be expected in a free living male bee, and has implications for our understanding of biological activity patterns and the evolution of forest pollinators.
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    Data from: Foraging and roosting behaviour of the fringe-lipped bat, Trachops cirrhosus, on Barro Colorado Island, Panamá
    (2017-12-18) Hämsch, Frank; O'Mara, M. Teague; Jones, Patricia L.
    The Neotropical fringe-lipped bat, Trachops cirrhosus, is a generalist predator that hunts frogs and insects by homing in on their mating calls. Although research has examined cognition and prey preferences of bats in captivity, little is known of the foraging or roosting behaviour of this species in the wild. We radio tracked six T. cirrhosus individuals on Barro Colorado Island, Panamá. Bat day roosts were all in hollow cashew trees, Anacardium excelsum, in mixed sex groups of three to five T. cirrhosus individuals, with frequent roost switching. Radio tracked individuals flew an average of 218 ± 227 m from their day roosts to 12.0 ± 10.17 ha foraging areas (50% utilization distribution [UD] kernels = area where bats spent 50% of their time as estimated from a probability distribution). These 50% UD kernels were less than 10% of their average total range use, but larger than previously reported for T. cirrhosus. Radio tracked individuals overlapped in 50% UD kernel foraging areas by only 2.1 ± 5.9 % on average. Foraging behaviour consisted predominantly of short sally flights of less than one minute, indicating bats were likely perch hunting. Bats were more frequently in flight, and had longer flight durations, at the beginning of the night and just before dawn than throughout the rest of the night. These data provide insight into the foraging behaviour of T. cirrhosus in the wild that is a species fast becoming a model system of cognition in captivity.
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    Data from: Spatial ecology of the water opossum Chironectes minimus in Atlantic Forest streams
    (2016-06-13) Leite, Melina de Souza; Galliez, Maron; Queiroz, Thiago Lopes; Pinto de Mendonça, Patrícia; Fernandez, Fernando A.S.
    The water opossum Chironectes minimus is the world’s only semi-aquatic marsupial. It is considered rare, and it is reported on several regional conservation lists of species as either endangered or data deficient. Given its uniqueness and the poor knowledge of its ecology, we aimed to investigate home range size and overlap and habitat selection of the water opossum in Atlantic Forest streams in southeastern Brazil. We radio tracked water opossums and collected information about their habitats and behaviour from October 2004 to April 2010. We combined common home range estimators for animals living in linear habitats with the synoptic model of home range and habitat selection. For the 10 individuals monitored, the home ranges varied between 0.80 and 9.66 km of watercourses; none of them had exclusive home ranges. The home range size for males was, on average, three times larger than for females. The overlap data showed that, on average, one male could encompass the home ranges of up to five females simultaneously, but more than one male could have access to the same female. For habitat selection at the individual level, we could not find any strong influence of habitat features on water opossum preferences because individuals selected different sets of habitat variables. However, at the population level, we found a negative relationship between home range size and river size. The water opossum seems to prefer shallow and narrow watercourses to establish its home ranges. Here, we present valuable information to advance our knowledge of the water opossum and its ecology, which is urgent for conservation purposes.
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    Data from: Cozy in the city: the morphology and spatial ecology of copperheads in an urban forest
    (2020-10-05) Carrasco-Harris, Malle F.; Cole, Judith A.; Reichling, Steve
    Anthropogenic environments alter behaviors in a wide variety of taxa. We examined the morphology and spatial ecology of Agkistrodon contortrix Linnaeus (Eastern Copperhead) within an urban forest and a rural forest in Tennessee. We captured snakes for morphological data and radio tracked 36 urban and 8 rural subjects to collect spatial data. We estimated home range size, core area, and movement parameters (total distance moved; daily, sampling, and monthly movement) using relocation data. Copperheads in the urban forest were smaller but did not differ in body condition compared to rural conspecifics. We found urban Copperheads had reduced home ranges, core areas, and movement parameters compared to rural subjects. Our study suggests urban snakes alter spatial behavior by decreasing overall movement.