S06.4: Population dynamics of the White-browed Scrubwren: Effects of social behaviour and wildfire

Australia Bird and Bat Banding Scheme, PO Box 8, Canberra 2601, Australia, e-mail belinda.dettmann@mgdestmx01.erin.gov.au

Studies of geographical and climatic patterns in survival frequently compare among species, but survival rates may also vary considerably within species. We used mark-recapture methods to estimate population parameters of White-browed Scrubwrens Sericornis frontalis in southern Australia. This small passerine lives in thick undergrowth in a diverse range of habitats from tropical rainforest to temperate heaths and deserts. It is a co-operative breeder employing a range of different mating tactics possibly influenced by habitat and environmental conditions. We studied the species at two forest sites at elevations of 740 and 1050 m. Scrubwrens had greater survival rates at the higher site. At each site adult survival was greater than that of juveniles, and survival for adult males was higher than for females, as might be expected from their polyandrous mating strategies. A wildfire at one site influenced many population parameters. Population size increased significantly after the fire but returned to pre-fire levels within four years. Annual survival of females declined dramatically. Recruitment of males was unaffected, but soared for females immediately post-fire and then crashed. These results show that social behaviour and environmental events are important sources of variation in population parameters of forest birds.

Note: Full paper not submitted.