Age structure and density of red-capped robin populations vary with habitat size and shape.
Abstract
In order to determine the influence of habitat shape on aspects of the population dynamics of birds, 196 male red-capped robins (Petroica goodenovii) were surveyed using song playback in large non-linear woodland remnants and linear roadside remnants in the wheat belt of south-eastern Australia. The average density of male robins was significantly higher in large non-linear remnants (0.86±0.09 birds/ha) than in small linear remnants (0.35±0.16 birds). Red-capped robins exhibited delayed plumage maturation, and 14% of the males captured were yearlings. This percentage was significantly higher in roadside remnants (20%) than in large, non-linear remnants (8%). It is considered that different population processes are occurring in the individual remnants and the dynamics of the metapopulation are potentially complex. It is recommended that land managers should not focus excessively on wildlife corridors (narrow, linear habitats) at the expense of appropriate management and restoration of large areas of native vegetation.