Split migrations

Split migrations are common in shorebirds and passerines, some of which moult over several weeks at a stopover site en route to winter quarters. Shorebird examples include some populations of Dunlin Calidris alpina, Curlew Sandpiper C. ferruginea and Purple Sandpiper C. maritima. Passerine examples include the Lazuli Bunting Passerina amoena, Western Tanager Piranga ludovi-ciana and Bullock's Oriole Icterus bullocki of western North America, the Great Reed Warbler Acrocephalus arundinacous, Garden Warbler Sylvia borin, Marsh Warbler Acrocephalus palustris and Thrush Nightingale Luscinia luscinia of western Eurasia-Africa, and the Yellow-breasted Bunting Emberiza aureola of eastern Eurasia (Young 1991, Stresemann & Stresemann 1966). In some western North American species, juveniles moult in breeding areas before migration, and adults at a staging site or in their wintering areas (Rohwer & Manning 1990, Butler et al. 2002). Some Common Starling Sturnus vulgaris populations in northern Europe show the opposite pattern, with adults remaining to moult in their breeding areas and juveniles migrating and moulting on a staging area (Chapter 15). Split migrations are also common in waterfowl, many of which first migrate to special sites where they moult, becoming flightless as they replace their large wing feathers (see 'Moult migrations', Chapter 16). Only after completing wing moult do the birds move on to wintering areas.

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