SEEN - SE European Bird Migration Network
Strategy of primary moult of adult Wood Sandpipers as an adaptation to sub-tropical conditions at southern African non-breeding grounds

Magdalena Remisiewicz1, Anna Gustowska1, Les G. Underhill2, Anthony J. Tree3, P. Barry Taylor4
1Avian Ecophysiology Unit, Dept. of Vertebrate Ecology and Zoology, Univ. of Gdańsk, al. Legionow 9,80-441 Gdańsk
2Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
3 Box 211, 6166 Bathurst, South Africa
4School of Biological and Conservation Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa

The course of primary moult in Wood Sandpiper (Tringa glareola) at its sub-Saharan non-breeding quarters has been poorly described due to limited data available. In this study we analysed primary moult protocols of 1497 adult Wood Sandpipers (in age 2+) from museum specimens (n=116) collected in 1900-1975 or ringed (n=1381) in 1966-2007 at their non-breeding grounds in southern Africa, applying the Underhill-Zucchini (1988) model and related software. Adult Wood Sandpipers arrive in southern Africa from the beginning of July and depart from mid-March. Among 747 birds in active moult, 7% showed suspended moult. The remaining birds commenced a continuous moult of the primaries, from P1 ascendantly, on 21 Aug on average. Moult lasted on average 131 days (SD=29 days) and 95% of birds commenced moult between 26 June and 16 Oct. This corresponds with arrivals of adults in southern Africa observed till ca 10 Oct. Development of the smaller inner primaries P1-P5 lasted 47 days on average, up to 4 primaries grew simultaneously, and the mean intershedding interval was 7 days. The large primaries P6-P10 were developed in 92 days on average, at the most 2 primaries grew at the same time, and the mean intershedding interval was 15 days. The overall rate of production of feather material was relatively constant throughout the whole season. Primary moult in adult Wood Sandpipers combines two strategies observed in other waders: quick and simultaneous growth of primaries observed in populations moulting in the northern hemisphere, and slow replacement of primaries typical for waders moulting in the southern hemisphere. Despite the relatively long moult, thanks to its early completion and the delayed fattening and departure, Wood Sandpipers earn as much as ca 2.5 months of ?slack? period between moult and migration, taking full advantage of stable sub-tropical conditions.

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