Migration and Wintering Locations of Breeding Eastern Willet (Tringa semipalmata semipalmata) in the Western Gulf of Mexico

Abstract. Knowledge of the geographic linking of individuals or populations between different annual life cycle stages is essential for effective conservation decision making. The Willet (Tringa semipalmata) is composed of two distinct subspecies that are separated by breeding habitat in North America, with eastern Willets breeding in estuarine marshes along the Atlantic and Gulf Coasts and western Willets breeding in wet grasslands and prairies in the interior west of North America. We studied the migratory paths and wintering locations of Texas Gulf Coast breeding eastern Willets from 2015 to 2019 using light-level geolocators. Data analysis from 9 retrieved geolocators indicated that all birds departed Texas 5-26 July, made a 2–5-day flight, and arrived on the wintering grounds 8–30 July. All birds wintered on the Pacific coasts of Central and South America. In spring, the birds departed the wintering location 9–24 March, made a 3–4-day flight and arrived on the breeding grounds 12–27 March. These results are in contrast to previous work which showed that Atlantic breeding eastern Willets overwintered on the Atlantic coast in northern South America. This work has implications for shorebird conservation planning, which currently considers all Willets overwintering on the Pacific coast to be western Willets.