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Use of wetlands at the mouth of the Yangtze River by shorebirds during spring and fall migration

2006; Association of Field Ornithologists; Volume: 77; Issue: 4 Linguagem: Inglês

10.1111/j.1557-9263.2006.00059.x

1557-9263

Zhen‐Ming Ge, Tianhou Wang, Xiao Yuan, Xiao Zhou, Wenyu Shi,

Fish Ecology and Management Studies

ABSTRACT The mouth of the Yangtze River is an important stopover site for migratory shorebirds using the East Asian-Australasian Flyway. From 1984 to 2004, we censused and banded shorebirds and monitored hunting activities at the mouth of the Yangtze River to understand how shorebirds used the study area. Counts and banding data revealed greater numbers of shorebirds at the mouth of the Yangtze River during northward migration (spring) than during southward migration (fall), with ratios varying from 1.5:1 to 7.2:1 at different sites from 1984 to 2005. The most common species observed during spring (northward) migration were Great Knots (Calidris tenuirostris), Red Knots (Calidris canutus), Bar-tailed Godwits (Limosa lapponica), Sharp-tailed Sandpipers (Calidris acuminata), and Red-necked Stints (Calidris ruficollis). During spring 2003–2004, 96.98% of the shorebirds observed were adults (ASY or older) and 3% were after hatching-year and second-year birds (AHY or SY). In contrast, almost all (94.73%) birds counted during the fall were hatching-year (HY) birds. These results indicate that adult shorebirds either use a different migration route during fall migration or use the same route, but do not stop at the mouth of the Yangtze River. HY birds, however, may depend on the coastal stopover sites for feeding during their first southward passage. La desembocadura del Rio Yangtze es un importante punto de parada de playeros migratorios que utilizan la vía del Este-Asiático-Australásico. De 1984 to 2004 anillamos playeros y se condujeron censos para monitorear las actividades de cacería en la desembocadura del Yangtze y ademásdeterminar como los playeros utilizaban dicha área. Los conteos de aves anilladas revelaron un mayor número de playeros durante la migración hacia el norte (primaveral) que durante la migración hacia el sur (otoñal) con una tasa de 1.5:1 a 7.2:1 en diferentes localidades. Las especies que se observaron con mayor frecuencia durante la primavera (moviéndose hacia el norte) fueron Calidris tenuirostris, C. canutus, C. acuminata, C. ruficollis y Limosa lapponica. Durante la primavera del 2003–2004, el 96.98% de las aves observadas fueron adultos y el 3% fueron aves de segundo año o juveniles del primer año. En contraste el 94.73% de las aves contabilizadas durante el otoño fueron juveniles del primer año. Estos resultados indican que los adultos utilizan otra ruta durante la migración otoñal o una ruta similar pero que no paran en la desembocadura del Yangtze. Sin embargo, las aves de primer año muy bien pudieran depender de los recursos alimentarios de los puntos de parada costaneros durante su primer viaje hacia el sur.