Use of the Swale Estuary, SE England, by Grey Plovers Pluvialis squatarola
213 – 225
1 December 16
Rodney Smith, Keith Derrett, Nicholas Tardivel
Swale Wader Group
Swale Wader Group, 67 York Avenue, Chatham, ME5 9ES, United Kingdom
Using counts and data on the primary moult and body mass of Grey Plover Pluvialis squatarola trapped on the Swale Estuary, SE England, over three decades, the ways in which nine distinct groups of Grey Plovers make use of the estuary between July and January are described. These comprise: (1) adults that stopover during southward migration, (2) adults that stop to carry out their flight-feather moult and remain for the winter, (3) adults that have started primary moult elsewhere and arrive in suspended moult, (4) adults that start primary moult on the Swale, suspend and move to complete elsewhere, (5) adults that carry out their whole primary moult on the Swale and then move to winter elsewhere, (6) juveniles that stopover during southward migration, (7) juveniles that stay for the winter, (8) first-summer birds that carry out their first large-feather moult and remain on the Swale for the winter, and (9) first-summer birds that carry out their first large-feather moult and then depart to winter elsewhere. The arrivals and departures of these distinct groups mean that many more Grey Plovers use the Swale than are indicated by the monthly counts, emphasising the conservation importance of the estuary for the species. The Swale Grey Plover population is of national importance in the United Kingdom and has sometimes exceeded the threshold of international importance in the East Atlantic Flyway.