Breeding and Flocking:Comparison of Seasonal Wetland Habitat Use by the Brolga Grus rubicunda in South-western Victoria

Abstract

Systematic investigation of temporal use of habitats by the Brolga Crus rubicunda is lacking, The aim of this study was to examine six wetland characteristics and their relation to Brolga flocking and breeding habitat for the south-western Victorian Brolga population, During the breeding season Brolgas were restricted to freshwater meadows and shallow freshwater marshes with an average water depth of 0,26 m (Standard Deviation, S,D, 0,06 m) and area of 15,71 ha (S,D, 18,04 ha), Breeding sites were characterised by having a substantial cover of emergent aquatic vegetation (mean 82.41 %, S,D, 12,72% ), which was significantly greater than th at recorded for flocking sites (Z = -5,863, df =56, P<O,OOl), In comparison, flocking sites had more variable salinity (fresh to saline), area (3,25-2565,17 ha) and wetland classification (shallow freshwater marsh to permanent saline), Flocking sites had significantly greater average water depth (t = - 5,542, df =56, P <0,001), wetland area (Z = -4,829, df =56, P <0,0001) and number of water sources (t = -6.472, df =56, P <0,0001) than breeding sites, Flocking sites potentially maintained summer inundation by being fed by two or more water sources (mean 2,21 , S,D, 0,68), This variable nature of habitats used by the Brolga and the variation in habitat use create a challenge for the effective long-term management and conservation of the species,