FEEDING BEHAVIOUR AND DMNG RHYTHMS OF SOME NEW ZEALAND SHAGS, PHALACROCORACIDAE

Abstract

Summary Records of the duration of the dives and resting periods of two species of Shags, which fish in the coastal waters of New Zealand's South Island, show the existence of an ecological segregation whereby each species is working within the limits of its greatest physiological efficiency. The smaller species hunts only in shallow water, the larger maintains efficient dive/rest ratios in deeper off‐shore water.