The effects of flock size, habitat type and cattle herd sizes on feeding and vigilance in cattle egrets (Ardeola ibis)

摘要

The most commonly documented association between birds and mammals is that between cattle egrets (Ardeola ibis) and cattle (Bos indicus) (Heatwole, 1965). The flocking behaviour of cattle egrets may decrease predation risk through increased group vigilance (Bertram. 1980), or predator confusion (Neill & Cullen, 19741. We tested for the relationship bet ween cattle herd sizes and egret flock sizes and examined whether individual egret vigilance would vary with egret flock size. We also investigated the effect of habitat type on vigilance behaviour.