Eastern-breeding Lesser Yellowlegs are more likely than western-breeding birds to visit areas with high shorebird hunting during southward migration

Shorebirds have experienced a precipitous reduction in abundance over the past four decades. While some threats to shorebirds are widespread (e.g., habitat alteration), others are regional and may affect specific populations. Lesser Yellowlegs (Tringa flavipes) are long-distance migrants that breed across the North American boreal biome and have declined in abundance by 60-80% since the 1970s. The documented harvest of Lesser Yellowlegs in the Caribbean and northeastern South America during southward migration is a possible limiting factor for the species, but it is unknown to what extent birds from different breeding origins may be affected. To address the question of differential occurrence in harvest zones during southward migration, we used PinPoint GPS Argos transmitters to track the southward migrations of 85 adult Lesser Yellowlegs from across the species' breeding range and 80 degrees of longitude from Anchorage, Alaska, USA, to the Mingan Archipelago, Quebec, Canada. We classified migratory locations as inside or outside three zones with high levels of harvest (Caribbean, coastal Guianas, and coastal Brazil) and then fit generalized additive mixed models to estimate the probability of occurrence of Lesser Yellowlegs in harvest zones according to their breeding origin. Individuals from the Eastern Canada population had a higher probability of occurrence within one or more harvest zones and remained in those zones longer than individuals breeding in Alaska and western Canada. Linear regressions also suggested that longitude of the breeding origin is an important predictor of occurrence in harvest zones during southward migration. Lastly, our findings, combined with other sources of evidence, suggest that current estimated harvest rates may exceed sustainable limits for Lesser Yellowlegs, which warrants further investigation. Lay Summary center dot The Lesser Yellowlegs is experiencing a steep population decline. Addressing longstanding knowledge gaps, such as the potential impact that unregulated harvest has on specific breeding populations, helps scientists and managers develop and implement effective conservation actions for this vulnerable species. center dot Using GPS telemetry, we tracked the southward migration of 85 adult Lesser Yellowlegs across the Western Hemisphere to establish the specific populations that migrate through areas with high harvest. center dot Lesser Yellowlegs originating from the eastern part of their migratory range were more likely than western-breeding birds to occur within jurisdictions in the Caribbean and northeastern South America where shorebird harvest occurs. center dot Without considering differential occurrence of Lesser Yellowlegs within harvest regions, their decline will likely continue, resulting in the loss of biodiversity and an important cultural resource.

Automated summary

Shorebirds, especially the Lesser Yellowlegs, have experienced a significant decline in abundance. The occurrence of Lesser Yellowlegs in harvest zones during southward migration is influenced by their breeding origin, especially the longitude of their breeding range. The estimated harvest rates may exceed sustainable limits, indicating the importance of further investigation and conservation efforts.