WADERS (CHARADRII) AND OTHER WATERBIRDS AT LANGEBAAN LAGOON, SOUTH AFRICA, 1975–1986

Summary

Underhill, L. G. 1987. Waders (Charadrii) and other waterbirds at Langebaan Lagoon, South Africa, 1975–1986. Osrrich 58: 145–155.

Langebaan Lagoon was surveyed for waterbirds at midsummer and midwinter between 1975 and 1986. The median number of birds counted in summer was 37 500, of which 34 500 were waders (93% of the waders being Palaearctic migrants). Curlew Sandpiper (59,2%), Grey Plover (10,5%), Sanderling (8,3%), Knot (8,1%) and Turnstone (5,7%) were the major components of the summer wader population. The median number of birds in winter was 10 500, of which 4500 were flamingos and 4000 waders. For Palaearctic waders, the median winter population was 11,5% of the median summer population, but varied between 2,5% and 30,1%. For species of wader which breed in the Taimyr Peninsula, Siberia, a three-year cycle in the numbers of birds overwintering was detected, with large numbers in 1977, 1980, 1983 and 1986. Birds feeding on invertebrates consumed 126,9 kJ m⁻² yr⁻¹, or 24% of the total production of invertebrates. Greater Flamingos have a major impact on energy cycling at Langebaan Lagoon, accounting for 73,3% of the winter energy consumption by the avifauna. Langebaan Lagoon is the most important wetland for waders in South Africa, accounting for about 10% of the coastal wader population of South Africa. At midsummer, about 0,5% of the total wader population of the East Atlantic Flyway is at Langebaan Lagoon, which ranks about 20th in importance for waders on the flyway.