Migratory Connectivity Research Articles

Low-coverage whole genome sequencing for highly accurate population assignment: Mapping migratory connectivity in the American Redstart (Setophaga ruticilla).

Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing methods, such as low-coverage whole genome sequencing (lcWGS), provides new opportunities for improved estimates of migratory connectivity. Here, we use lcWGS to identify fine-scale population structure in a widespread songbird, the American Redstart (Setophaga ruticilla), and accurately assign individuals to genetically distinct breeding populations. Assignment of individuals from the nonbreeding range reveals population-specific patterns of varying migratory connectivity. By combining migratory connectivity results with demographic analysis of population abundance and trends, we consider full annual cycle conservation strategies for preserving numbers of individuals and genetic diversity. Notably, we highlight the importance of the Northern Temperate-Greater Antilles migratory population as containing the largest proportion of individuals in the species. Finally, we highlight valuable considerations for other population assignment studies aimed at using lcWGS. Our results have broad implications for improving our understanding of the ecology and evolution of migratory species through conservation genomics approaches.

Investigating connectivity and seasonal differences in wind assistance in the migration of Common Sandpipers

Many migratory bird species have undergone recent population declines, but there is considerable variation in trends between species and between populations employing different migratory routes. Understanding species‐specific migratory behaviours is therefore of critical importance for their conservation. The Common Sandpiper Actitis hypoleucos is an Afro‐Palaearctic migratory bird species whose European populations are in decline. We fitted geolocators to individuals breeding in England or wintering in Senegal to determine their migration routes and breeding or non‐breeding locations. We used these geolocator data in combination with previously published data from Scottish breeding birds to determine the distributions and migratory connectivity of breeding (English and Scottish) and wintering (Senegalese) populations of the Common Sandpiper, and used simulated random migrations to investigate wind assistance during autumn and spring migration. We revealed that the Common Sandpipers tagged in England spent the winter in West Africa, and that at least some birds wintering in Senegal bred in Scandinavia; this provides insights into the links between European breeding populations and their wintering grounds. Furthermore, birds tagged in England, Scotland and Senegal overlapped considerably in their migration routes and wintering locations, meaning that local breeding populations could be buffered against habitat change, but susceptible to large‐scale environmental changes. These findings also suggest that contrasting population trends in England and Scotland are unlikely to be the result of population‐specific migration routes and wintering regions. Finally, we found that birds used wind to facilitate their migration in autumn, but less so in spring, when the wind costs associated with their migrations were higher than expected at random. This was despite the wind costs of simulated migrations being significantly lower in spring than in autumn. Indeed, theory suggests that individuals are under greater time pressures in spring than in autumn because of the time constraints associated with reproduction.

Comparing migratory connectivity across species: The importance of considering the pattern of sampling and the processes that lead to connectivity

Measuring the degree of migratory connectivity – how much and where different populations of species mix as they migrate over their annual cycle – is important because it informs the understanding of the evolution of migration, how populations will be affected by both habitat and climate change, and which areas to prioritize for conservation. But existing measures of connectivity may be difficult to compare because they measure different things and are confounded by sampling bias. Here we use tagging data from all available published landbird tracks up to July 2019 (224 populations, 86 species and 1524 individuals tracked in the three main global flyways) to identify robust measures to compare migratory connectivity across species. We consider two widely used descriptive measures: (1) degree of breeding population overlap on the non‐breeding grounds and (2) Mantel correlation, which tests the degree of spatial autocorrelation between the breeding and non‐breeding individuals; as well as one causative measure of the main process that leads to connectivity patterns: migratory spread of individuals from the same breeding population across the non‐breeding area. We investigated the sensitivity of these three measures to the distance between breeding locations of sampled populations (breeding distance) and their sample size. We also considered the confounding effects of migration distance because longer migrations decreased overlap and increased Mantel correlations and migratory spread. We found that the degree of overlap between breeding populations on the non‐breeding grounds decreased with increasing breeding distance and increased with increasing sample size. Mantel correlation coefficients also increased significantly with increasing breeding distance; sample size did not affect accuracy, but precision was greatly improved above a sample size of about 15 individuals. Migratory spread, however, was independent of breeding distance; sample size had only small effects on accuracy and precision, with no significant effects when more than four individuals per population were included. Furthermore, migratory spread was highly positively correlated with the maximum non‐breeding range. Overlap and Mantel correlations were highly confounded by the spatial pattern and amount of sampling, whereas migratory spread was relatively unconfounded, even by migratory distance. Although any descriptive migratory connectivity measure can help set priorities by determining current areas for conservation on the non‐breeding grounds, migratory spread, which leads to these patterns, needs fewer data, is comparable, and gives information on evolutionary flexibility and so ability to deal with changing habitat and climate.

Multi-isotope (δ2H, δ13C, δ15N) feather profiles and morphometrics inform patterns of migratory connectivity in three species of North American swallows

Aerial insectivorous birds have suffered steep population declines in North America over the last 60 years. A lack of information on migratory connectivity between breeding and non-breeding grounds for these species limits our ability to interpret factors affecting their population-specific trends. We determined likely Latin American non-breeding regions of Bank (Riparia riparia), Barn (Hirundo rustica) and Cliff (Petrochelidon pyrrhonota) swallow from populations across their breeding ranges. We used predicted feather hydrogen (δ2Hf) and carbon (δ13Cf) isoscapes for winter-grown feathers to indicate areas of highest probability of moult origin and incorporated these results into a cluster analysis to determine likely broad non-breeding regions. We also assessed variation in wing length among populations to determine the potential for this metric to differentiate population moult origins. We then investigated patterns of multi-isotopic (δ2Hf, δ13Cf, δ15Nf) and wing-length niche occupancy by quantifying niche size and overlap among populations under the assumption that broad niches were consistent with low within-species migratory connectivity and narrow and non-overlapping niches with higher connectivity. Multivariate assignment identified different non-breeding regions and potential clusters of moult origin generally corresponding to Central America and northern South America, eastern and south-central South America, and the western and southern part of that continent, with variation within and among populations and species. Separate niche space indicated different wintering habitat or areas used by species or populations whereas niche overlap indicated only potential spatial similarity. Wing length varied significantly among populations by species, being longer in the west and north for Bank and Cliff Swallow and longer in eastern Canadian Barn Swallow populations. Barn Swallow occupied consistently larger isotopic and wing length niche space than the other species. Comparisons among populations across species showed variable isotopic and wing-length niche overlap generally being greater within breeding regions and lower between western and eastern breeding populations supporting a general North American continental divide for all species with generally low migratory connectivity for all species. We present a novel approach to assessing connectivity using inexpensive and broad isotopic approaches that provides the basis for hypothesis testing using more spatially explicit expensive techniques.

Lesser kestrels of the same colony do not overwinter together.

Migratory connectivity describes the linkage between breeding and nonbreeding sites, having major ecological implications in birds: 1 season influence the success of an individual or a population in the following season. Most studies on migratory connectivity have used large-scale approaches, often considering regional populations, but fine-scale studies are also necessary to understand colony connectivity. The lesser kestrel Falco naumanni, an insectivorous migratory raptor which form colonies during the breeding period, was considered to have strong connectivity based on regional populations. However, no small-scale studies on migratory connectivity have been conducted. Therefore, we GPS (Global Positioning System)-tracked 40 adult lesser kestrels from 15 different Spanish breeding colonies, estimating the overlap index between home ranges and the distance between their centroids. It was found that lesser kestrels from the same breeding colony placed their nonbreeding areas at 347 ± 281 km (mean ± standard deviation) away from each other (range = 23-990), and their home ranges overlapped by 38.4 ± 23.6%. No differences between intra-colony and inter-colony metrics were found, which suggests that lesser kestrels from the same breeding cluster do not overwinter together, but they spread out and mixed independently of the colony belonging throughout the nonbreeding range of the species. Ultimately, this study highlights the importance of performing connectivity studies using fine-scale approaches.

Habitat use, survival, and migration of a little-known East Asian endemic, the yellow-throated bunting Emberiza elegans.

Basic information on the ecology of species is key for their conservation. Here we study the ecology of the little-known yellow-throated bunting Emberiza elegans based on a multi-year study on its breeding grounds in the Russian Far East. For the first time in this species, we quantified breeding habitat parameters, calculated sex-specific apparent survival, and determined individual nonbreeding locations using light-level geolocation. We found that the habitat around song posts of male yellow-throated buntings is characterized by tree and shrub layers on richly littered moist ground. Habitat use overlaps with co-occurring Tristram's Buntings Emberiza tristrami and Black-faced Buntings E. spodocephala, but territories differ especially in tree cover and litter cover. Based on 4 years of color-ringing data of 72 individuals, we calculated an apparent survival rate of 36%, with higher survival estimates for male than for female yellow-throated buntings. We found no effect of carrying a geolocator on survival. We retrieved six geolocators from males. All birds migrated south-westward during autumn and spent the nonbreeding season at locations in China 700-1700 km away from their breeding sites. At least two individuals spent the boreal winter outside of the known range in northern or central China. Birds left the breeding area between early October and early November and returned between mid-March and mid-April. Our data on habitat use, survival rate, and migratory connectivity will help to assess threats to the populations of this enigmatic species, which might include habitat loss due to forest fires on the breeding grounds, and unsustainable harvest for consumption during the nonbreeding season.

Intra‐ and interspecific variation in trace element concentrations in feathers of north European trans‐African migrants

The knowledge of migratory connectivity is important for understanding the potential drivers of populations and it is thus important for conservation implications. Migratory connectivity of species can be studied using exogenous, such as rings and transmitters, or endogenous markers, such as stable isotopes and trace elements. The use of trace elements has been much less frequently studied compared to stable isotopes. Trace elements can be studied from the feathers of birds and this does not necessarily require trapping of individuals. Here we studied the variation of 18 different trace elements in feathers of two long‐distance trans‐African migrants, willow warblers Phylloscopus trochilus and barn swallows Hirundo rustica, using body feathers of museum specimens of birds from Finnish breeding grounds. The trace elements were measured using laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA‐ICP‐MS). We show that trace element concentrations were relatively stable along the rachis within the same feather except in Ni and S, which showed a quadratic pattern. In general, variation within feathers of the same individuals was smaller than in feathers between individuals for most elements. Furthermore, concentrations of 11 trace elements showed significantly higher concentrations in willow warbler feathers collected in spring than in autumn, moulted in African wintering grounds and European breeding grounds, respectively. Last, concentrations of seven trace elements were significantly higher in the spring feathers of willow warblers compared to barn swallows. This suggests that trace elements could be used to separate moulting grounds of the birds on the larger scale within the same species, but also sampling design should be carefully considered.

Management of U.S. Agricultural Lands Differentially Affects Avian Habitat Connectivity

Despite frequently being implicated in species declines, agricultural lands may nonetheless play an important role in connecting wildlife populations by serving as movement corridors or stopover sites between areas of high-quality habitat. For many North American bird species, agricultural intensification over the past half century has substantially impacted populations, yet recent studies have noted the potential for supporting avian biodiversity on agricultural lands through the promotion of functional connectivity. To support avian conservation efforts on agricultural lands across the United States, we used publicly available data from eBird to quantify and map the effects of agriculture on habitat suitability (using random forest models) and functional connectivity (via circuit theory) for three focal species that have experienced agriculture-linked declines or range contractions in recent decades: Greater Sage-grouse (Centrocercus urophasianus), American Black Duck (Anas rubripes), and Bobolink (Dolichonyx oryzivorus). Our analysis drew on novel, remotely sensed estimates of agricultural management intensity to quantify the effects of management practices on avian habitat and movement, revealing complex, species-specific relationships between agriculture and habitat value for the three focal species. Rangelands and croplands exhibited relatively high connectivity values for Greater Sage-grouse and Bobolink, respectively, mirroring these species’ strong habitat preferences for open sagebrush and cultivated grasslands. By contrast, American Black Duck migratory connectivity was low on all agricultural cover types. Mapping our model results across each species’ geographic range in the U.S. revealed key areas for agricultural management action to preserve high-quality habitat and connectivity, and we link these spatial recommendations to government incentive programs that can be used to increase wildlife-friendly management on U.S. agricultural lands.

Minimizing Data Waste: Conservation in the Big Data Era

Minimizing Data Waste: Conservation in the Big Data Era

Non‐reproductive dispersal: an important driver of migratory range dynamics and connectivity

Dispersal is the primary ecological process underpinning spatial dynamics in motile species by generating flux in reproductive locations over time. In migratory species, dispersal can also occur around non‐breeding ranges, but this form currently lacks a unifying theoretical framework. We present a novel conceptual model for dispersal in migrants that builds upon existing literature, differentiating ‘reproductive' dispersal (i.e. changes in breeding locations) from ‘non‐reproductive' dispersal, which we define as movements resulting in inter‐annual or inter‐generational changes in non‐breeding locations. Crucially, unlike reproductive dispersal where movement outcomes are naturally propagated between generations, the outcomes of non‐reproductive dispersal can be non‐heritable. We use simulations of a solo‐migrant population with a genetically encoded migratory programme to illustrate how variation in this heritability exerts a strong influence on both migratory connectivity and range shift propensity. When exposed to spatially uncoupled shifts in habitable ranges (i.e. seasonal climate niches shifting at different rates), long‐term persistence of simulated populations required changes in migratory programmes to arise through heritable forms of non‐reproductive dispersal (e.g. mutations in migratory gene complexes). By contrast, non‐heritable dispersal mechanisms (e.g. navigation errors) cannot drive long‐term shifts in non‐breeding ranges, despite being a major component of realised dispersal and migratory connectivity patterns. Migratory connectivity metrics conflate these heritable and non‐heritable drivers of non‐reproductive dispersal, and therefore have limited power in predicting population responses to environmental change. Our models provide a framework for improving our understanding of spatial dynamics in migratory populations, and highlight the importance of teasing apart the mechanisms that drive migratory variability in order to evaluate and predict range plasticity in migrants.

New insight into migration patterns of western North Pacific humpback whales between the Babuyan Islands, Philippines and the Commander Islands, Russia

The population structure of humpback whales (Megaptera novaeangliae) in the North Pacific has received significant attention in recent years through the collaborative Structure of Populations, Levels of Abundance, and Status of Humpback whales in the North Pacific (SPLASH) study. However, the analysis of humpback whales in the western North Pacific Asian population was limited in the SPLASH study, due to small sample size. Much of the Asian population summers off Kamchatka, Russia and spends the winters in breeding grounds in Okinawa and Ogasawara, Japan and the Babuyan Islands in the northern Philippines. Prior studies grouped the Commander Islands feeding ground in Russia, with the eastern Aleutian Islands as part of the central humpback whale stock. This paper uses additional years of photo-ID data from both the Philippines (160 whales from 2000–12) and the Commander Islands (531 whales from 2008–10) to establish a previously unreported migratory connection by matching four animals between the two sites. The new migratory linkage found in the present study suggests that a small portion of humpback whales hypothesised to be migrating to a ‘missing’ breeding ground in the central North Pacific are actually migrating to the Philippines. However, additional studies on a wider geographical scale are required.

Winter connectivity and leapfrog migration in a migratory passerine.

Technological advances in migratory tracking tools have revealed a remarkable diversity in migratory patterns. One such pattern is leapfrog migration, where individuals that breed further north migrate to locations further south. Here, we analyzed migration patterns in the Painted Bunting (Passerina ciris) using a genetic-based approach. We started by mapping patterns of genetic variation across geographic space (called a genoscape) using 386 individuals from 25 populations across the breeding range. We then genotyped an additional 230 samples from 31 migration stopover locations and 178 samples from 16 wintering locations to map patterns of migratory connectivity. Our analyses of genetic variation across the breeding range show the existence of four genetically distinct groups within the species: Eastern, Southwestern, Louisiana, and Central groups. Subsequent assignment of migrating and wintering birds to genetic groups illustrated that birds from the Central group migrated during the fall via western Mexico or southern Texas, spent the winter from northeastern Mexico to Panama, and migrated north via the Gulf Coast of Mexico. While Louisiana birds overlapped with Central birds on their spring migratory routes along the Gulf Coast, we found that Louisiana birds had a more restricted wintering distribution in the Yucatan Peninsula and Central America. Further estimation of the straight-line distance from the predicted breeding location to the wintering location revealed that individuals sampled at lower winter latitudes traveled to greater distances (i.e., the predicted breeding area was further north; p> .001), confirming that these species exhibit a leapfrog migration pattern. Overall, these results demonstrate the utility of a genoscape-based approach for identifying range-wide patterns of migratory connectivity such as leapfrog migration with a high degree of clarity.

Migratory connectivity of North American waterfowl across administrative flyways.

Management of waterfowl that migrate seasonally across North America occurs within four flyways that were delineated in the early 1900s to include the annual movements of populations. Movements may have changed over the past century since the administrative flyways were established, and may do so while management plans are in use, so information about transitions among flyways through time can illustrate how management assumptions may change. Today there are more than 12 million records from 60 years of migratory waterfowl band recoveries to assess adaptive management approaches that will be most effective when they account for movements within and between flyways. We examined how much the movement of North American waterfowl occurs between flyways, whether those movements have changed through time, and whether movements of mallards are representative of multiple species, as suggested by current harvest management strategies. We estimated the probability a duck would transition from one flyway to another and the strength of migratory connectivity (MC) for each species within and among flyways. We used capture-mark-recovery models to estimate population-specific movement within and among flyways (transition probabilities) for 15 migratory waterfowl species that were banded during breeding and recovered during winter. We developed new functionality in the R package MigConnectivity to estimate the species-specific strength of MC using transition probability samples from the capture-mark-recovery models. We found the regular movement of duck populations among flyways, overall weak MC, and no consistent change in migratory movements through time. Mallard movements were median among all duck species, but significantly different from many species, particularly diving ducks. Despite the significant movement between flyways, our work suggests flyway management of waterfowl matches many of the seasonal movements of these species when considering mid-continent flyway management. We recommend models accounting for all transition probabilities between populations and regularly estimating harvest derivations, transition probabilities, and MC metrics to verify that the current movements match model assumptions.

MIGRATORY CONNECTIONS IN WATERFOWL OF NORTHERN WESTERN SIBERIA, BASED ON RING-RECOVERY DATA

Migratory connections in waterfowl in the north of Western Siberia are discussed as based on ring recoveries from the database of the Bird Ringing Center of Russia, A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences. Altogether, 3531 recoveries from waterfowl of 29 species were used. The waterfowl in the region are characterized by exceptionally wide migratory connections, occurring in different seasons in most regions of the Old World within the Northern Hemisphere: from Iceland to the Japanese Islands and from West Africa to the Indian Subcontinent and the Yangtze River basin. The long-distance flights of birds to molting sites, the interannual change of nesting grounds and wintering regions, as well as the distribution on wintering grounds are discussed. Ten wintering regions have been allocated. The available material on the migration of waterfowl is evaluated from the viewpoint of completing the description of their seasonal distribution and its significance in the study of ecological connections of the territory of Western Siberia.

Light-level geolocation reveals moderate levels of migratory connectivity for declining and stable populations of Black-throated Blue Warblers ( Setophaga caerulescens )

Light-level geolocation reveals moderate levels of migratory connectivity for declining and stable populations of Black-throated Blue Warblers ( Setophaga caerulescens )

The strength of migratory connectivity in Painted Buntings is spatial scale dependent and shaped by molting behavior

The strength of migratory connectivity in Painted Buntings is spatial scale dependent and shaped by molting behavior

Trends and progress in studying butterfly migration

AbstractSeveral hundred butterfly species show some form of migratory behaviour. Here we identify how the methodologies available for studying butterfly migration have changed over time, and document geographic and taxonomic foci in the study of butterfly migration. We review publications on butterfly migration published in six languages (English, Simplified Chinese, Traditional Chinese, Japanese, Korean, and Spanish), summarise how migration in butterflies has been studied, explore geographic and taxonomic patterns in the knowledge base, and outline key future research directions. Using English search keywords, we found only 58 studies from Asia; however, after searching in local languages, we found an additional 98 relevant studies. Overall, butterfly migration studies are mostly from North America and Europe. Most studies focus on three species: monarch (Danaus plexippus), painted lady (Vanessa cardui) and red admiral (Vanessa atalanta). About 62% of publications are focused on the monarch, with nearly 50% of migratory butterfly species mentioned in only a single paper. Several research methods have been applied to ascribe migratory status and to study the physiology, neurobiology, and ecology of migration; however, virtually all this research is on a handful of species. There remain hundreds of species for which we do not understand the comprehensive seasonal pattern of movement, flight destinations, wintering, or breeding grounds. A better understanding of movement ecology and migratory connectivity is needed to effectively conserve migratory butterflies. It is essential that research becomes more geographically and linguistically representative since migrants frequently cross political borders and international cooperation is necessary for their conservation.

A cold high-pressure system over North China hinders the southward migration of Mythimna separata in autumn

BackgroundIn warm regions or seasons of the year, the planetary boundary layer is occupied by a huge variety and quantity of insects, but the southward migration of insects (in East Asia) in autumn is still poorly understood.MethodsWe collated daily catches of the oriental armyworm (Mythimna separata) moth from 20 searchlight traps from 2014 to 2017 in China. In order to explore the autumn migratory connectivity of M. separata in East China, we analyzed the autumn climate and simulated the autumn migration process of moths.ResultsThe results confirmed that northward moth migration in spring and summer under the East Asian monsoon system can bring rapid population growth. However, slow southerly wind (blowing towards the north) prevailed over the major summer breeding area in North China (33°–40° N) due to a cold high-pressure system located there, and this severely disrupts the autumn ‘return’ migration of this pest. Less than 8% of moths from the summer breeding area successfully migrated back to their winter-breeding region, resulting in a sharp decline of the population abundance in autumn. As northerly winds (blowing towards the south) predominate at the eastern periphery of a high-pressure system, the westward movement of the high-pressure system leads to more northerlies over North China, increasing the numbers of moths migrating southward successfully. Therefore, an outbreak year of M. separata larvae was associated with a more westward position of the high-pressure system during the previous autumn.ConclusionThese results indicate that the southward migration in autumn is crucial for sustaining pest populations of M. separata, and the position of the cold high-pressure system in September is a key environmental driver of the population size in the next year. This study indicates that the autumn migration of insects in East China is more complex than previously recognized, and that the meteorological conditions in autumn are an important driver of migratory insects’ seasonal and interannual population dynamics.

Tracking Device Attachment Methods for American Kestrels: Backpack Versus Leg-Loop Harnesses

ABSTRACT The American Kestrel (Falco sparverius) is a small falcon whose population is declining across North America, but drivers of this decline have yet to be identified. Conservationists have called for greater understanding of kestrels' migratory connectivity to identify potential causes of decline that may occur during various parts of their annual cycle. For many bird species, the most common and direct way to determine migratory connectivity is by attaching a tracking device that documents their locations over time. However, American Kestrels present a challenge when attaching tracking devices due to their small size and aggressive biting capabilities. We used two attachment methods (backpack and leg-loop harnesses) commonly used for raptors on a wintering population of American Kestrels in north Texas to test whether there were differences in observed return rates the following year. Of 20 American Kestrels fit with devices, significantly more of the kestrels fit with backpack harnesses were observed the following winter than the birds fit with leg-loop harnesses. Eight of the 10 kestrels we fit with backpacks were observed to return to their winter territories compared to only two of 10 kestrels fit with leg-loops. Overall return frequency data of kestrels with both harnessing methods (50%, n = 20) was similar to the frequency we observed on marked birds without devices (52%, n = 190), though this was heavily skewed due to the high return of birds with backpack harnesses (80%). Although our sample size was limited, the disparity between the return rates of birds with the two harness types suggests that backpack harnesses are the preferred method of attaching tracking devices to American Kestrels, and also potentially to similar small raptor species.

Flyway-scale GPS tracking reveals migratory routes and key stopover and non-breeding locations of lesser yellowlegs.

Many populations of long-distance migrant shorebirds are declining rapidly. Since the 1970s, the lesser yellowlegs (Tringa flavipes) has experienced a pronounced reduction in abundance of ~63%. The potential causes of the species' decline are complex and interrelated. Understanding the timing of migration, seasonal routes, and important stopover and non-breeding locations used by this species will aid in directing conservation planning to address potential threats. During 2018-2022, we tracked 118 adult lesser yellowlegs using GPS satellite tags deployed on birds from five breeding and two migratory stopover locations spanning the boreal forest of North America from Alaska to Eastern Canada. Our objectives were to identify migratory routes, quantify migratory connectivity, and describe key stopover and non-breeding locations. We also evaluated predictors of southbound migratory departure date and migration distance. Individuals tagged in Alaska and Central Canada followed similar southbound migratory routes, stopping to refuel in the Prairie Pothole Region of North America, whereas birds tagged in Eastern Canada completed multi-day transoceanic flights covering distances of >4000 km across the Atlantic between North and South America. Upon reaching their non-breeding locations, lesser yellowlegs populations overlapped, resulting in weak migratory connectivity. Sex and population origin were significantly associated with the timing of migratory departure from breeding locations, and body mass at the time of GPS-tag deployment was the best predictor of southbound migratory distance. Our findings suggest that lesser yellowlegs travel long distances and traverse numerous political boundaries each year, and breeding location likely has the greatest influence on migratory routes and therefore the threats birds experience during migration. Further, the species' dependence on wetlands in agricultural landscapes during migration and the non-breeding period may make them vulnerable to threats related to agricultural practices, such as pesticide exposure.