SEASONAL ABUNDANCE, BIOMASS AND FEEDING OF SHORE BIRDS ON SANDY BEACHES IN THE EASTERN CAPE, SOUTH AFRICA

Abstract

McLachlan, A., Woodridge, T., Schramm, M. & Kühn, M. 1980. Seasonal abundance, biomass and feeding of shore birds on sandy beaches in the Eastern Cape, South Africa. Ostrich 51:44-52. The numbers of birds on three Eastern Cape sandy beaches were monitored monthly over one year during 1977/78. Dominant among 17 species were the Southern Blackbacked Gull Larus dominicanus, Black Oystercatcher Haematopus moquini, Whitefronted Sandplover Charadrius marginatus and Sanderling Calidris alba. These four species made up 95% of bird numbers and their respective biomass values were 78 652, 7 695, 578 and 3 116 kJ/km shoreline. Total food consumption for these species, calculated on the basis of estimated standard metabolic rates, was 4 159 394, 521 149, 76 768 and 363 053 kJ/km respectively. Food composition and feeding behaviour are also discussed and the total quantity of intertidal macrobenthic animals consumed by birds estimated.