Observations on nesting of shoebill Balaeniceps rex and wattled crane Bugeranus carunculatus in Malagarasi wetlands, western Tanzania

摘要

Findings of the first ground study on nests of shoebill and wattled crane in Tanzania, made between 2005 and 2011, were reported. The study was conducted in the central drainage basin of the Malagarasi-Moyowosi Ramsar Site. Nests were located by wading, canoeing and remote observation of nesting birds using binoculars and spotting scopes. A total of 18 nests were recorded, of which 13 and 5 nests were of shoebill and wattled crane, respectively. Of the 13 shoebill nests, 7 were successful, and only 2 nests of wattled crane hatched. Birds, especially shoebill, abandoned nests mostly before egg laying. No specific period for nesting was found, although more shoebill hatching happened as the flood receded (July to September). Nests for both species were located in short-lying vegetation dominated by four plant species (Oryza longistaminata, Eleocharis dulcis, Leersia hexandra and Typha capensis). Nests were constructed using surrounding vegetation that included several other Cyperus spp. Shoebill nests were surrounded by water and were placed in permanent marshes, whereas wattled crane nested in flooded grasslands. This study confirmed that shoebill and wattled crane bred successfully in the Malagarasi wetlands. No specific nesting season could be derived from the small sample size, however, it seemed that nesting started at high floods.