US EPA

8048197 

Journal Article 

Complementary use of intertidal mudflats and adjacent salinas by foraging waders 

Masero, JA; Perez-Hurtado, A; Castro, M; Arroyo, GM 

2000 

Yes 

Ardea
ISSN: 0373-2266 

88 

2 

177-191 

WOS:000165527100006 

The use of intertidal mudflats and adjacent supratidal salinas by foraging waders was studied, including a time-foraging budget in winter and during the period prior to the spring migration. The predictions of three hypotheses that might explain why waders use the supratidal habitat, 'preference, disturbance and supplementary food hypotheses', are discussed. Intertidal mudflats and salinas were used in a complementary manner by waders in winter and during the pre-migration period, as the majority of the total populations of many wader species forage at low tide on the mudflats in winter, while during the pre-migration period several of these species forage mainly in the salina at low tide, as numbers decrease on the intertidal area. The total densities of waders feeding on the intertidal area were exceptionally high, with an average (+/- SE) density of 98.3 +/- 7.1 birds ha(-1) in winter. It is likely that the salina contributes significantly to the maintenance of the high density of foraging waders on the mudflats. The results of this study seem to support the 'supplementary food hypothesis' for Oystercatcher Haematopus ostralegus, Grey Plover Pluvialis squatarola, Turnstone Arenaria interpres, Bar-tailed Godwit Limosa lapponica, Knot Calidris canutus, Kentish Plover Charadius alexandrinus and Ringed Plover C. hiaticula. The 'preference hypothesis' was also supported for Dunlin Calidris alpina, Sanderling C. alba, Little Stint C. minuta, Curlew Sandpiper C. ferruginaea, Red-shank Tringa tetanus and Black-tailed Godwit Limosa limosa. The 'disturbance hypothesis' was not supported by the results. 

foraging; intertidal mudflats; preference hypothesis; salt-pans; shorebirds; supratidal habitats