Habitat use pattern of three species of egrets in a small coastal lagoon in Ghana

Abstract

The foraging and pattern of habitat use of Western Reef Heron Egretta gularis, Little Egret Egretta garzetta and Great Egret Egretta alba were studied in Sakumo II Lagoon in Ghana to determine the extent of utilisation of non-fish resources by these species, which compete with humans for fisheries resources. The species were counted in grassland and marginal water areas of the lagoon on the assumption that individuals found in the grassland area feed on non-fish resources, whereas those in marginal water forage on fish and possibly aquatic invertebrates. Average numbers of E. gularis and E. garzetta making use of the grassland were higher than those utilising the water, indicating preference for the grassland area. Egretta alba did not show a preference for either habitat. Catch per unit effort and swallow rates of each species were similar in grassland and water habitats, with the exception of E. alba, which recorded a higher swallow rate in grassland. It was concluded that the grassland habitats of Sakumo II Lagoon are important for ardeids, and that non-fish resources constitute an important food for ardeids in coastal Ghana, contrary to previous observations.

Keywords: arthropods, Egretta, fish, human-wildlife conflict, niche segregation, waterbirds

OSTRICH 2013, 84(3): 213–217