Sensor:Solar Geolocator Raw
Solar Geolocator Raw
No Thumbnail Available
Name
Solar Geolocator Raw
External ID
solar-geolocator-raw
Is Location Sensor
3 results
Search Results
Now showing 1 - 3 of 3
- Data packageData from: Light-level geolocation reveals wintering distribution, migration routes, and primary stopover locations of an endangered long-distance migratory songbird(2017-02-01) Cooper, Nathan W.; Hallworth, Michael T.; Marra, Peter P.The importance of understanding the geographic distribution of the full annual cycle of migratory birds has been increasingly highlighted over the past several decades. However, the difficulty of tracking small birds between breeding and wintering areas has hindered progress in this area. To learn more about Kirtland's warbler Setophaga kirtlandii movement patterns throughout the annual cycle, we deployed archival light-level geolocators across their breeding range in Michigan. We recovered devices from 27 males and analyzed light-level data within a Bayesian framework. We found that most males wintered in the central Bahamas and exhibited a loop migration pattern. In both fall and spring, departure date was the strongest predictor of arrival date, but in spring, stopover duration and migration distance were also important. Though stopover strategies varied, males spent the majority of their spring migration at stopover sites, several of which were located just before or after large ecological barriers. We argue that loop migration is likely a response to seasonal variation in prevailing winds. By documenting a tight link between spring departure and arrival dates, we provide a plausible mechanism for previously documented carry-over effects of winter rainfall on reproductive success in this species. The migratory periods remain the least understood periods for all birds, but by describing Kirtland's warbler migration routes and timing, and identifying locations of stopover sites, we have begun the process of better understanding the dynamics of their full annual cycle. Moreover, we have provided managers with valuable information on which to base future conservation and research priorities.
- Data packageData from: Breeding latitude predicts timing but not rate of spring migration in a widespread migratory bird in South America(2019-04-01) Jahn, Alex E.; Cereghetti, JoaquĂn; Cueto, Victor R.; Hallworth, Michael T.; Levey, Douglas J.; Marini, Miguel Ă‚.; Masson, Diego; Pizo, Marco A.; Sarasola, JosĂ© Hernán; Tuero, Diego T.(1) Identifying the processes that determine avian migratory strategies in different environmental contexts is imperative to understanding the constraints to survival and reproduction faced by migratory birds across the planet. (2) We compared the spring migration strategies of Fork-tailed Flycatchers (Tyrannus s. savana) that breed at south-temperate latitudes (i.e., austral migrants) vs. tropical latitudes (i.e., intra-tropical migrants) in South America. We hypothesized that austral migrant flycatchers are more time-selected than intra- tropical migrants during spring migration. As such, we predicted that that austral migrants, which migrate further than intra-tropical migrants, will migrate at a faster rate and that the rate of migration for austral migrants will be positively correlated with the onset of spring migration. (3) We attached light-level geolocators to Fork-tailed Flycatchers at two tropical breeding sites in Brazil and at two south-temperate breeding sites in Argentina and tracked their movements until the following breeding season. (4) Of 286 geolocators that were deployed, 37 were recovered ~1 year later, of which 28 provided useable data. Rate of spring migration did not differ significantly between the two groups, and only at one site was there a significantly positive relationship between date of initiation of spring migration and arrival date. (5) This represents the first comparison of individual migratory strategies among conspecific passerines breeding at tropical vs. temperate latitudes and suggests that austral migrant Fork-tailed Flycatchers in South America are not more time- selected on spring migration than intra-tropical migrant conspecifics. Low sample sizes could have diminished our power to detect differences (e.g., between sexes), such that further research into the mechanisms underpinning migratory strategies in this poorly understood system is necessary.
- Data packageData from: Concentration of a widespread breeding population in few critically important nonbreeding areas: migratory connectivity in the Prothonotary Warbler(2019-07-03) Tonra, Christopher M.; Hallworth, Michael T.; Boves, Than J.; Reese, Jessie; Bulluck, Lesley P.; Johnson, Matthew; Viverette, Cathy; Percy, Katie; Ames, Elizabeth M.; Matthews, Alix; Slevin, Morgan C.; Wilson, R. Randy; Johnson, Erik I.One of the greatest challenges to informed conservation of migratory animals is elucidating spatiotemporal variation in distributions. Without such information, it is impossible to understand full-annual-cycle ecology and effectively implement conservation actions that address where and when populations are most limited. We deployed and recovered light-level geolocators (n = 34) at 6 breeding sites in North America across the breeding range of a declining long-distance migratory bird, the Prothonotary Warbler (Protonotaria citrea). We sought to determine migratory routes, stopover location and duration, and the location of overwintering grounds. We found that the species exhibits a large-scale, east‒west split in migratory routes and weak migratory connectivity across its range. Specifically, almost all individuals, regardless of breeding origin, overlapped in their estimated wintering location in northern Colombia, in an area 20% the size of the breeding range. Additionally, most of the individuals across all breeding locations concentrated in well-defined stopover locations in Central America while en route to Colombia. Although error inherent in light-level geolocation cannot be fully ruled out, surprisingly much of the estimated wintering area included inland areas even though the Prothonotary Warbler is considered a specialist on coastal mangroves in winter. Based on these results, conservation efforts directed at very specific nonbreeding geographical areas will potentially have benefits across most of the breeding population. Our findings highlight the importance of using modern technologies to validate assumptions about little-studied portions of a species’ annual cycle, and the need to distribute sampling across its range.