THE NEST‐BUILDING BEHAVIOUR OF THE MAGPIE GOOSE ANSERANAS SEMIPALMATA

Abstract

SUMMARYMagpie Geese Anseranas semipalmata build substantial nests of vegetation in the extensive Eleocharis/Oryza swamps of Northern Australia. Building activity begins some two months before the eggs are laid, and a large number of stages and preliminary nests are built before the true nest. It is thought that males generally initiate and take a large share in nest‐building. Experimental evidence suggests that building activity is greatly intensified in wet weather.Field observations show that the nests are always placed in swamps, the vegetation of which lies within a specific range of height and density. Experimental work with captive birds is described and analyzed, and suggests that such precise habitat selection results from the behavioural integration of two orientation components. One is an innate tendency to build with up‐and‐down elements in the environment. The other tendency, acquired only after experience, is to build with those elements of the environment that have certain characteristics of height and density. The learning process involved in the acquisition of the latter tendency is thought to be reinforced by the rapid completion of a satisfactory stage.