AbstractThe Grey-crowned Babbler, Pomatostomus temporalis, is a medium-sized sedentary bird that lives in groups of three to eight individuals and breeds cooperatively. In the southern states of Australia it is threatened, mostly by habitat fragmentation. Although the species is still common and widespread in northern Australia, only one study prior to this has focussed on their breeding biology in this part of Australia. As the savannas that dominate the vegetative landscape of the Northern Territory are prone to frequent fire during the dry season (May to October), it is reasonable to suggest that fire has some impact on the reproductive biology of Babblers.
Analysis of breeding data gathered at Coomalie Farm, Northern Territory covering five years, combined with satellite imagery and spatial data revealed that breeding success of the Babbler groups was low but comparable with Babblers in southern Australia. The group size of the Babblers at Coomalie Farm ranged from 2-8 individuals and average group size varied little between years. Nesting success and the number of fledglings produced was positively correlated with group size. However, when analysis was considered as reproductive output per individual adult bird group size and fledgling numbers were negatively correlated; as group size increased, fledgling numbers decreased.
Fires occurred regularly at the study site and their timing overlapped with the Babbler breeding season. A series of spatial analysis conducted within a Geographic Information System (GIS) showed no direct impact of fire on Babbler breeding success. Whilst the results of this study hint that fire might influence the breeding success of the Grey-crowned Babbler in the northern savannas, analyses using the data available were unable to demonstrate any statistical significant association.
Further research involving clear definition of Babbler territories and a more complete fire history would enable the impact of fire on breeding success to be better understood.
|Date of Award||Jul 2011|
|Supervisor||Diane Pearson (Supervisor), Richard Noske (Supervisor) & John Woinarski (Supervisor)|