Movements of Cormorants in South Eastern Australia and the Influence of Flood on Breeding

Abstract

Examination of flood regimes in inland south-east Australia showed that natural flooding was an important factor in initiating breeding of cormorants, as were small localized artificial floods. Recovery data for banded great, little black and little pied cormorants were examined to assess dispersal patterns from natal colonies. Dispersal of great cormorants was more marked than that of little pied and little black cormorants; many great cormorants from the lower Murray moved upstream. Such dispersal led to the occasional influx of large numbers of birds into the permanent cooler waters of the eastern region of the Murray-Darling system. A case study was examined; it is suggested that the increase in great cormorant numbers can be forecast and should be used to determine the time at which fish are stocked, in order to improve fish survival.