Residency and Movement Patterns of Wintering Dunlin in the Willamette Valley of Oregon

• Published in: The Condor
• Main Authors: Sanzenbacher, Peter M., Haig, Susan M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2002
• Subjects: Calidris alpina; Dunlin
• Online Access: http://dx.doi.org/10.1093/condor/104.2.271; http://academic.oup.com/condor/article-pdf/104/2/271/29711885/condor0271.pdf

Abstract In the winters of 1998–1999 and 1999–2000, we tracked 67 radio-marked Dunlin (Calidris alpina) throughout the complex agricultural landscape of the Willamette Valley of Oregon. Individual birds were tracked across 8-week sampling periods and indicated a high degree of regional fidelity throughout the three winter sampling periods. Birds exhibited varied degrees of fidelity to specific wetland sites and were detected at an average of nine different sites. Distances traveled within the region were extensive and greatest during late winter. Females ranged farther from capture sites than males, and movement from capture sites for all birds was greatest during late winter. Mean home-range size (95% minimum convex polygons) of birds was 258.2 ± 44.8 km2 (SE) and was greatest during late winter. Diurnal roosts were identified as centers of activities and daily movements were most pronounced during crepuscular periods. These data represent the most extensive documentation of winter movements for a shorebird at an inland site. Findings indicate Dunlin were winter residents, and extensive local movements suggest a high degree of functional connectivity of habitats. Residencia y Patrones de Movimiento de Calidris alpina en el Valle Willamette de Oregon Resumen. En los inviernos de 1998–1999 y 1999–2000, seguimos 67 individuos de Calidris alpina marcados con transmisores a través del complejo paisaje agrícola del Valle Willamette, Oregon. Seguimos aves individuales a lo largo de períodos de 8 semanas de muestreo, que indicaron un alto nivel de fidelidad regional a través de los tres períodos invernales muestreados. Las aves exhibieron diversos grados de fidelidad a sitios específicos de los humedales y fueron detectadas en promedio en nueve sitios diferentes. Las distancias recorridas dentro de la región fueron grandes y mayores durante el final del invierno. Las hembras se desplazaron a mayores distancias desde los sitios de captura que los machos, y el movimiento de todas las aves desde los sitios de captura fue ...