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311 results for “Migrants”
Data from: Measures of oxidative state are primarily driven by extrinsic factors in a long-distance migrant
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Environmental drivers of annual population fluctuations in a trans-Saharan insect migrant
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Data from: Juveniles and migrants as drivers for seasonal epizootics of avian influenza virus
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Data from: Timing manipulations reveal the lack of a causal link across timing of annual-cycle stages in a long-distance migrant
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Data from: Interspecific social information use in habitat selection decisions among migrant songbirds
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Data from: Wind-associated detours promote seasonal migratory connectivity in a flapping flying long-distance avian migrant
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Data from: Diet dichotomy between two migrant seabirds breeding near a high Arctic polynya
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Data from: Seasonal detours by soaring migrants shaped by wind regimes along the East Atlantic Flyway
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Data from: Extreme altitudes during diurnal flights in a nocturnal songbird migrant
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Data from: Time-keeping programme can explain seasonal dynamics of leukocyte profile in a migrant bird
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Recurrence, fidelity, and proximity to previously visited sites throughout the annual cycle in a trans-Saharan migrant, the Common Cuckoo
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Data for: Early-life behavior predicts first-year survival in a long-distance avian migrant
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Data from: The influence of climate variability on demographic rates of avian Afro-palearctic migrants
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Feather mercury increases with feeding at higher trophic levels in two species of migrant raptors, Merlin (Falco columbarius) and Sharp-shinned Hawk (Accipiter striatus)
<p>Mercury (Hg) is a toxic heavy metal that, when methylated to form methylmercury (MeHg), bioaccumulates in exposed animals and biomagnifies through food webs. The purpose of this study was to assess Hg concentrations in raptors migrating through the upper Midwestern USA. From 2009-2012, 966 raptors of 11 species were captured at Hawk Ridge, Duluth, MN. Breast feathers were sampled to determine the concentration of total Hg. Mean Hg concentrations ranged from 0.11 – 3.46 μg g<sup>-1</sup> fresh weight across species and were generally higher in raptors that feed on birds in comparison with those that feed on mammals. To evaluate the effect of dietary sources on Hg biomagnification, carbon and nitrogen stable isotope ratios were measured in feathers of the two species with the highest Hg concentrations, Merlin (<i>Falco columbarius</i>) and Sharp-shinned Hawk (<i>Accipiter striatus</i>). Measured δ<sup>13</sup>C values were similar in both species and indicated a primarily terrestrial-derived diet, whereas δ<sup>15</sup>N values suggested that individual Merlin and Sharp-shinned Hawk feeding at higher trophic levels accumulated higher concentrations of Hg. The risk to birds associated with measured levels of feather Hg was evaluated by calculating blood-equivalent values using an established algorithm. Predicted blood values were then compared to heuristic risk categories synthesized across avian orders. This analysis suggested that while some Merlin and Sharp-shinned Hawk were at moderate risk to adverse effects of MeHg, most of the sampled birds were at negligible or low risk.</p>
Earlier and slower or later and faster: Spring migration pace linked to departure time in a Neotropical migrant songbird
<p><span>1. Migratory birds travel vast distances and the timing of migratory flights can affect survival and the ability to reproduce. For Neotropical migrant songbirds, <span>early spring departure from wintering sites, early arrival to the breeding grounds and higher reproductive success have been related to the use of suitable habitats and environmental conditions during the non-breeding season. However, how migratory strategies are shaped by winter habitat choice is largely unknown due to the general </span>inability to track birds from specific wintering habitats to stopovers or breeding destinations<span>. </span></span></p> <p><span>2. We assessed how winter habitat (native forest vs. shade-grown coffee plantations) relates to spring departure date and migration pace in Swainson's Thrush (<i>Catharus ustulatus</i>). We also determined the effect of departure date and total migration duration on the arrival date of birds detected near or within their breeding range. </span></p> <p><span>3. We used a novel application of Motus radio telemetry arrays to track individuals from their wintering grounds in the Andes of South America along their migratory journey to North America.</span></p> <p><span>4. We found variation in migratory strategies between habitats, with birds wintering in native forest departing later than birds in coffee. We present isotopic evidence for native forest being of higher quality than shade coffee for Swainson's Thrush and hypothesize that moister conditions in forest, as shown by stable isotope (δ<sup>13</sup>C) analysis of thrush whole blood, provides favourable pre-migratory conditions allowing birds to delay departure from wintering grounds. Habitat, between-site and -year variation in departure date, suggests that birds made facultative adjustments to winter habitat quality and environmental conditions. Independent of habitat, birds that departed later migrated faster and this pattern was maintained along the migration route (<i>n</i> = 44). <span>Migrating earlier and slower or later and faster was unlikely to result in significant differences in arrival time to breeding destinations. </span></span></p> <p><span><span>5. Our</span></span> findings reveal underappreciated complexity in migratory decisions by long-distance migrants that contrast with the current paradigm of earlier departures and arrival from optimal habitats. The next step is to understand the relative fitness benefits of early versus late schedules or whether each strategy is an equally good response to experienced conditions.</p>
Using stable isotopes to estimate migratory connectivity for a patchily distributed, wetland-associated Neotropical migrant
<p>Estimates of migratory connectivity are needed for full annual cycle population models of migratory bird species experiencing rapid declines in abundance. One technique to determine migratory connectivity is through stable isotope analysis. This low-resolution method may be influenced by how data are calibrated between isotopes measured in precipitation and those measured in feathers, and can be informed by incorporating relative abundance into the assignment model. eBird abundance maps are a new tool combining citizen science data into a predictive species distribution model. In the Prothonotary Warbler (Protonotaria citrea), a wetland-associated songbird with a patchy breeding distribution, we sought to use stable-hydrogen isotope analysis informed by a species-specific calibration equation and eBird abundance data to determine the strength of migratory connectivity. We developed a species-specific calibration equation using known-origin samples from the breeding grounds and found that stable-hydrogen isotope values measured in precipitation explained 50% of the variation in stable-hydrogen isotope values among feathers. We found that the assignment model incorporating eBird abundance data correctly identified the true origins of 66% of individuals, and that the average assignment area (as a measure of precision) was 64% of the breeding distribution. These results represented a 7% increase in precision and a 3% decrease in accuracy when compared to a model that was not informed by abundance. Based on these models, wintering populations from 6 countries represented a mix of likely breeding origins, suggesting low migratory connectivity for Prothonotary Warblers. We found evidence that wintering latitude was related to likely breeding origin, with individuals at western wintering locations more likely to have southern breeding origins, but this relationship was weak. These results corroborate studies using archival light-level geolocators and high-resolution genetic markers, which also demonstrated weak migratory connectivity in this species. For patchily distributed species, eBird abundance data may not provide a useful increase in precision and accuracy for isotope assignments.</p>
Local human population increase in the non-breeding areas of long-distance migrant bird species is only weakly associated with their declines, even for synanthropic species
<p><span>Aim: To show how recent declines in populations of long-distance migrant birds are associated with recent increases in human population growth and agricultural intensification on their tropical non-breeding grounds, except for synanthropic species, where we expect the reverse.</span></p> <p><span>Location: Breeding populations throughout Europe and North America spending the non-breeding season throughout Africa, and Central and South America, respectively. </span></p> <p><span>Methods: </span>We mapped 50 species of long-distance migrant birds from published tagging studies of 126 breeding populations and identified their breeding population trends from 2000-2015 from published Country or State census data. We then matched individual bird non-breeding locations, from each population, to local human population change and crop yield data. We used GLMs to predict whether bird population decline was associated with human population change or crop yield and whether this was dependent on if a species was synanthropic or not, controlling for absolute human population density, breeding and non-breeding location, migratory distance and phylogeny. We predicted that bird populations that spend the non-breeding season in areas of recent higher human population increase or agricultural intensification (crop yield), would show greater declines, but that declines would be less for species that frequently utilize anthropogenic habitats such as secondary woodland and farmland.</p> <p><span>Results: </span>Bird population change, even for synanthropic species, showed a significant negative relationship with relative human population change and crop yield (but this was weak, <2% and 6% of variance respectively), and this relationship was the same for the Neotropics and Africa, despite African human population change being three times larger.</p> <p><span>Main conclusions: </span>The results suggest that local human population change in the non-breeding area is likely to be only a relatively minor driver of migrant declines, and its effects may be through increases in agricultural intensification reducing carrying capacity but we currently lack local studies to confirm this.</p>
Data from: A single migrant enhances the genetic diversity of an inbred puma population
Migration is essential for maintaining genetic diversity among populations, and pumas (Puma concolor) provide an excellent model for studying the genetic impacts of migrants on populations isolated by increasing human development. In densely populated southern California, USA, puma populations on the east and west side of interstate highway 15 (I-15) have become fragmented into a small inbred population on the west side (Santa Ana Mountains) and a relatively larger, more diverse population on the east side (Eastern Peninsular Range). From 146 sampled pumas, genetic analyses indicate seven pumas crossed I-15 over the last 15 years, including four males from west to east, and three males from east to west. However, only a single migrant (named M86) was detected to have produced offspring and contribute to gene flow across the I-15 barrier. Prior to the M86 migration, the Santa Ana population exhibited inbreeding and had significantly lower genetic diversity than the Eastern Peninsular Range population. After M86 emigrated, he sired 11 offspring with Santa Ana females, decreasing inbreeding measures and raising heterozygosity to levels similar to pumas in the Eastern Peninsular Range. The emigration of M86 also introduced new alleles into the Santa Ana population, although allelic richness still remained significantly lower than the Eastern Peninsular population. Our results clearly show the benefit of a single migrant to the genetics of a small, isolated population. However, ongoing development and habitat loss on both sides of I-15 will increasingly strengthen the barrier to successful migration. Further monitoring, and potential human intervention, including minimizing development effects on connectivity, adding or improving freeway crossing structures, or animal translocation, may be needed to ensure adequate gene flow and long-term persistence of the Santa Ana puma population.
Data from: Genetic differentiation and selection against migrants in evolutionarily replicated extreme environments
We investigated mechanisms of reproductive isolation in livebearing fishes (genus Poecilia) inhabiting sulfidic and nonsulfidic habitats in three replicate river drainages. Although sulfide spring fish convergently evolved divergent phenotypes, it was unclear if mechanisms of reproductive isolation also evolved convergently. Using microsatellites, we found strongly reduced gene flow between adjacent populations from different habitat types, suggesting that local adaptation to sulfidic habitats repeatedly caused the emergence of reproductive isolation. Reciprocal translocation experiments indicate strong selection against immigrants into sulfidic waters, but also variation among drainages in the strength of selection against immigrants into nonsulfidic waters. Mate choice experiments revealed the evolution of assortative mating preferences in females from nonsulfidic but not from sulfidic habitats. The inferred strength of sexual selection against immigrants (RIs) was negatively correlated with the strength of natural selection (RIm), a pattern that could be attributed to reinforcement, whereby natural selection strengthens behavioral isolation due to reduced hybrid fitness. Overall, reproductive isolation and genetic differentiation appear to be replicated and direct consequences of local adaptation to sulfide spring environments, but the relative contributions of different mechanisms of reproductive isolation vary across these evolutionarily independent replicates, highlighting both convergent and nonconvergent evolutionary trajectories of populations in each drainage.
Data from: Simulated moult reduces flight performance but overlap with breeding does not affect breeding success in a long-distance migrant
1. Long-distance migrants are time-constrained as they need to incorporate many annual cycle stages within a year. Migratory passerines moult in the short interval between breeding and migration. To widen this interval, moult may start while still breeding, but this results in flying with moulting wings when food provisioning. 2. We experimentally simulated wing gaps in breeding male pied flycatchers by plucking 2 primary feathers from both wings. We quantified the nest visitations of both parents, proportion of high-quality food brought to the nestlings and adults and nestlings condition. Differences in oxidative damage caused by a possible reduction in flight efficiency were measured in amounts of ROMs and OXY in the blood. We also measured how flight performance was affected with recordings of the male`s escape flight using high-speed cameras. Finally, we collected data on adult survival, clutch size and laying date in the following year. 3. "Plucked" males travelled a 5% shorter distance per wingbeat, showing that our treatment reduced flight performance. In line with this, "plucked" males visited their nests less often. Females of "plucked" males, however, visited the nest more often than controls, and fully compensated their partner's reduced visitation rate. As a result, there were no differences between treatments in food quality brought to the nest, adult or chick mass or number of successfully fledged chicks. Males did not differ in their oxidative damage or local survival to the following year. In contrast, females paired with plucked males tended to return less often to breed in the next year in comparison to controls, but this difference was not significant. For the birds that did return there were no effects on breeding. 5. Our results reveal that wing gaps in male pied flycatchers reduce their flight performance, but when it occurs during breeding they prioritise their future reproduction by reducing parental care. As a result, there is no apparent detriment to their condition during breeding. Because non-moulting females are able to compensate their partner's reduced care, there is also no immediate costs to the offspring, but females may pay the cost suffering from a reduced survival.
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.