Sensor:Solar Geolocator Raw
Solar Geolocator Raw
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Solar Geolocator Raw
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- Data packageData from: Trans-equatorial migration links oceanic frontal habitats across the Pacific Ocean: year-round movements and foraging activity of a small gadfly petrel(2024-01-22) Clay, Thomas A.; Brooke, MdeL.Gadfly petrels are among the widest-ranging birds and inhabit oceanic regions beyond the legislative protection of national jurisdictions (the High Seas). Detailed information on breeding phenology, at-sea distributions, and habitat requirements is crucial for understanding threats and designing conservation measures for this highly threatened group. We tracked 10 Stejneger’s petrels Pterodroma longirostris, endemic to Isla Alejandro Selkirk, Juan Fernández Islands in the southeast Pacific Ocean, with geolocator-immersion loggers over two years to examine year-round movements, phenology, habitat use, and activity patterns. Birds conducted round-trip trans-equatorial migrations of 54,725 km to the northwest Pacific Ocean between Hawaii and Japan. Across the boreal summer, birds followed the c. 1000 km northward movement of the North Pacific Transition Zone Chlorophyll Front, before their return migration which took a long detour south toward New Zealand before heading east at 40–50°S, presumably benefitting from Antarctic circumpolar winds. To our knowledge, a comparable triangular migration is unique among seabirds. During the pre-laying exodus, birds traveled southwest to the Sub-Antarctic Front, and unlike congeners, there was no evidence of sexual segregation. Foraging areas during incubation were similar to pre-laying, with trips lasting 13 d and taking birds up to 4810 km southwest of the colony. Petrels spent > 75% of their time flying during breeding and migration, yet flight activity was substantially lower during non-breeding, presumably due to flight feather molt. Birds spent 87% of their time at sea within the High Seas and their apparent preference for oceanic frontal regions demonstrates the importance of protecting these remote habitats.
- Data packageData from: Spatiotemporally variable snow properties drive habitat use of an Arctic mesopredator(2023-08-16) Glass, Thomas W.; Robards, Martin D.Climate change is rapidly altering the composition and availability of snow, with implications for snow-affected ecological processes, including reproduction, predation, habitat selection, and migration. How snowpack changes influence these ecological processes is mediated by physical snowpack properties, such as depth, density, hardness, and strength, each of which is in turn affected by climate change. Despite this, it remains difficult to obtain meaningful snow information relevant to the ecological processes of interest, precluding a mechanistic understanding of these effects. This problem is acute for species that rely on particular attributes of the subnivean space, for example depth, thermal resistance, and structural stability, for key life-history processes like reproduction, thermoregulation, and predation avoidance. We used a spatially explicit snow evolution model to investigate how habitat selection of a species that uses the subnivean space, the wolverine, is related to snow depth, snow density, and snow melt on Arctic tundra. We modeled these snow properties at a 10 m spatial and a daily temporal resolution for 3 years, and used integrated step selection analyses of GPS collar data from 21 wolverines to determine how these snow properties influenced habitat selection and movement. We found that wolverines selected deeper, denser snow, but only when it was not undergoing melt, bolstering the evidence that these snow properties are important to species that use the Arctic snowpack for subnivean resting sites and dens. We discuss the implications of these findings in the context of climate change impacts on subnivean species.
- Data packageData from: Study "Switzerland Biel - Long term study on migratory movement of Alpine swifts (Apus melba)"(2020-11-26) Meier, Christoph M.; Liechti, FelixFor migratory birds optimal timing of the onset of reproduction is vital, especially when suitable conditions for reproduction occur only for a short while during the year. With increasing latitude the suitable period becomes shorter and we expect the organization of annual cycle to be more synchronized to the local conditions across individuals of same population. This should result in low variation of arrival and departure date in breeding sites at higher latitudes. We quantify the temporal and geographical variation in pre‐ and post‐breeding migration between individuals from four different populations of alpine swifts Tachymarptis melba along a latitudinal gradient. We tracked 215 individuals in three years with geolocators. The two western and two eastern populations showed separate migratory flyways and places of residence in Africa. Length of stay at the breeding sites was negatively correlated with latitude and differed by more than a month between populations. Duration of migration was similarly short in all populations (median 6.2 days in autumn and 8.7 days in spring). However, variation in timing of migration was unrelated to latitude and individuals everywhere arrived in the same asynchrony at the breeding site.
- Data packageData from: White-crested Elaenias (Elaenia albiceps chilensis) breeding across Patagonia exhibit similar spatial and temporal movement patterns throughout the year(2024-04-02) Jara, Rocío Fernanda; Jiménez, Jaime Enrique; Ricardo, RozziFor migratory birds, events happening during any period of their annual cycle can have strong carry-over effects on the subsequent periods. The strength of carry-over effects between non-breeding and breeding grounds can be shaped by the degree of migratory connectivity: whether or not individuals that breed together also migrate and/or spend the non-breeding season together. We assessed the annual cycle of the White-crested Elaenia (Elaenia albiceps chilensis), the longest-distance migrant flycatcher within South America, which breeds in Patagonia and spends the non-breeding season as far north as Amazonia. Using light-level geolocators, we tracked the annual movements of elaenias breeding on southern Patagonia and compared it with movements of elaenias breeding in northern Patagonia (1,365 km north) using Movebank Repository data. We found that elaenias breeding in southern Patagonia successively used two separate non-breeding regions while in their Brazilian non-breeding grounds, as already found for elaenias breeding in the northern Patagonia site. Elaenias breeding in both northern and southern Patagonia also showed high spread in their non-breeding grounds, high non-breeding overlap among individuals from both breeding sites, and similar migration phenology, all of which suggests weak migratory connectivity for this species. Elucidating the annual cycle of this species, with particular emphasis on females and juveniles, still requires further research across a wide expanse of South America. This information will be critical to understanding and possibly predicting this species’ response to climate change and rapid land-use changes.
- Data packageData from: Migratory routes of red-necked phalaropes Phalaropus lobatus breeding in southern Chukotka revealed by geolocators(2018-06-13) Mu, Tong; Tomkovich, Pavel S.; Loktionov, Egor Y.; Syroechkovskiy, Evgeny E.; Wilcove, David S.The migration routes of Red‐necked Phalaropes breeding around the Bering Sea are poorly known, despite the fact that the Bering Sea could mark the boundary between the East Palearctic populations that winter in the Pacific Ocean around the East Indies and the West Nearctic populations that winter in the Pacific Ocean off the coast of South America. Geolocator data retrieved from two male phalaropes tagged in southern Chukotka, Far Eastern Russia, confirm that birds breeding in this region belong to the East Palearctic population and winter in the East Indies, suggesting that the division line with the West Nearctic population is farther to the East. The routes taken by the two phalaropes were almost entirely pelagic, totaling around 18,000–20,000 km round‐trip, with the birds continuously on the move during migration, rather than resident in any particular stopover site, contrary to most other migratory shorebirds.
- 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, Joaquín; Cueto, Victor R.; Hallworth, Michael T.; Levey, Douglas J.; Marini, Miguel Â.; Masson, Diego; Pizo, Marco A.; Sarasola, José 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: Migration of red-backed shrikes from the Iberian Peninsula: optimal or sub-optimal detour?(2017-03-23) Tøttrup, Anders P.; Pedersen, Lykke; Onrubia, Alejandro; Thorup, KasperNOTE: An updated and larger version of this dataset is available. See https://doi.org/10.5441/001/1.4bt7365c. ABSTRACT: The current Northern Hemisphere migration systems are believed to have arisen since the last glaciation. In many cases, birds do not migrate strait from breeding to non-breeding areas but fly via a detour. All western European populations of red-backed shrikes Lanius collurio are assumed to reach their southern African wintering grounds detouring via southeast Europe. Based on theoretical considerations under an optimality framework this detour is apparently optimal. Here, we use individual geolocator data on red-backed shrikes breeding in Spain to show that these birds do indeed detour via southeast Europe en route to southern Africa where they join other European populations of red-backed shrikes and return via a similar route in spring. Disregarding potential wind assistance, the routes taken for the tracked birds in autumn were not optimal compared to crossing the barrier directly. For spring migration the situation was quite different with the detour apparently being optimal. However, when considering potential wind assistance estimated total air distances during autumn migration were overall similar and the barrier crossing shorter along the observed routes. We conclude that considering the potential benefit of wind assistance makes the route via southeast Europe likely to be less risky in autumn. However, it cannot be ruled out that other factors, such as following a historical colonisation route could still be important.
- Data packageData from: Seasonal variation in migration strategies used to cross ecological barriers in a Nearctic migrant wintering in Africa(2019-05-20) Léandri-Breton, Don-Jean; Lamarre, Jean-François; Bety, JoëlEcological barriers such as oceans, mountain ranges or glaciers can have a substantial influence on the evolution of animal migration. Along the migration flyway connecting breeding sites in the North American Arctic and wintering grounds in Europe or Africa, Nearctic species are confronted with significant barriers such as the Atlantic Ocean and the Greenland icecap. Using geolocation devices, we identified wintering areas used by Ringed Plovers nesting in the Canadian High‐Arctic and investigated migration strategies used by these Nearctic migrants along the transatlantic route. The main wintering area of the Ringed Plovers (n = 20) was located in Western Africa. We found contrasting seasonal migration patterns, with Ringed Plovers minimizing continuous flight distances over the ocean in spring by making a detour to stop in Iceland. In autumn, however, most individuals crossed the ocean in one direct flight from Southern Greenland to Western Europe, as far as Southern Spain. This likely resulted from prevailing anti‐clockwise winds associated with the Icelandic low‐pressure system. Moreover, the plovers we tracked largely circumvented the Greenland icecap in autumn, but in spring, some plovers apparently crossed the icecap above the 65°N. Our study highlighted the importance of Iceland as a stepping‐stone during the spring migration and showed that small Nearctic migrants can perform non‐stop transatlantic flights from Greenland to Southern Europe.
- Data packageData from: Non‐breeding areas and timing of migration in relation to weather of Scottish‐breeding common sandpipers Actitis hypoleucos(2019-02-01) Summers, Ron W.; de Raad, A. Louise; Bates, Brian; Etheridge, Brian; Elkins, NormanThe number of breeding common sandpipers has declined in Britain due to poorer return rates from non‐breeding areas. To investigate little known aspects of their annual cycle, breeding common sandpipers were fitted with geolocators to track their migrations and determine their non‐breeding areas. Ten tagged birds left Scotland on 9 July (median dates and durations are given throughout the abstract). Short‐term staging was carried out by some birds in England and Ireland, then for longer by most birds in Iberia before continuing to West Africa, arriving on 28 July. Six birds spent most of the non‐breeding season (October–February) on the coast of Guinea‐Bissau, suggesting that this is a key area. Single birds occurred in Sierra Leone, Guinea, the Canary Islands and Western Sahara. The southward migration from Scotland took 17.5 days (range 1.5‐24 days), excluding the initial fuelling period. The first northward movement from Africa was on 12 April. Staging occurred in either Morocco, Iberia or France. Arrival in Scotland was on 2 May. The northward migration took 16 days (range 13.5‐20.5 days). The main migration strategy involved short‐ and medium‐range flights, using tail‐winds in most cases. Variation in strategy was associated with departure date; birds that left later staged for shorter durations. Coastal West Africa provides two major habitats for common sandpipers: mudflats associated with mangroves and rice fields. Although the area of mangrove has been depleted, the scale of loss has probably been insufficient to account for the decline in sandpiper numbers. Rice fields are expanding, providing feeding areas for water‐birds. Meteorological data during the migrations suggest that the weather during the southward migration is unlikely to contribute to a population decline but strong cross‐winds or head‐winds during the northward migration to the breeding grounds may do so.
- 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.