Numbers, migration phenology and survival of Purple Sandpipers Calidris maritima at Gourdon, eastern Scotland

Purple Sandpipers wintering on the Kincardine coast had (a protracted autum n arrival (one-quarter and three-quarters of the birds arrived on 30 July a nd 21 October respectively, 83 days) but a faster spying departure (one-qua rter and three-quarters departed on 9 April and 27 May respectively, 48 day s). The long arrival period was partly due to differences in the migration phenology of the two main wintering populations: short-billed birds from No rway arrived before the long-billed birds, probably from Canada. There was a smaller difference in departure times of the two populations: short-bille d birds left before the long billed birds. Minimum annual survival was esti mated from resightings of 92 marked birds. There was no evidence that survi val differed between adults and first-years or between birds of different b ill-size classes, which were of different sex and geographical origin. Mini mum annual survival was estimated to be 79.5% (se = 2.8%). The similarity b etween the mortality rate (20.5%) and the percentage of first-year birds in populations of Purple Sandpipers probably reflects balanced population dyn amics.