Primary moult strategies in adult migrant waders (Charadrii)
126 – 137
1 September 22
Colin H.W. Jackson, Leslie G. Underhill
Leslie G. Underhill
Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
Biodiversity and Development Institute, 25 Old Farm Road, Rondebosch, 7700, South Africa
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We assembled the results of moult studies for 57 populations of 24 species of migrant waders which moult in the period between their southward and northward migrations. We used studies in which the Underhill-Zucchini moult model had been used to estimate the duration of primary moult and its mean starting date. Study sites were between 70°N and 38°S. We created three zones: north of 30°N, between 30°N and 30°S, and south of 30°S. We found that north of 30°N, moult patterns were constrained by the onset of cold winter weather; the timing of moult was relatively early and the duration was short. Moult duration was positively correlated with body mass. South of 30°S, the main constraint on moult patterns was the relatively short period between arrival and departure on the non-breeding grounds. Generally, in this zone the timing of moult was similar for all species, and the duration of moult was extended to cover the time available, ca. 120 days. This is thought to be a strategy to enable the growth of good quality feathers, capable of enduring long migration distances. In this southern zone, there was no relation between moult duration and body mass. Between 30°N and 30°S, moult patterns were less constrained, and there was considerable variation in both timing and duration of moult. With little environmental seasonality and day length variation, local conditions are thought to influence both the timing and duration of moult. This exploratory meta-analysis reveals patterns, highlights data gaps, and suggests hypotheses for further research.