Productivity and survival of Southern Scrub-robins in the South Australian Murray Mallee

Abstract

The Southern Scrub-robin Drymodes brunneopygia is an Australian ground-foraging insectivorous bird that has suffered dramatic declines in the South Australian Murray Mallee, and within this region is now largely confined to four isolated patches (clusters) of territories on one privately owned farm at = Bakara. In order to determine if Scrub-robins fare better in some habitats than others, colour-banded adults were intensively tracked to determine their productivity and survival in four habitat patches over a 3-year period between 2008 and 2011. At Bakara, survival of adult Scrub-robins was possibly lower in the North-west patch than in other patches. Most pairs were observed to breed; breeding started in late September/early October and lasted c. 1 month. Thirty-two percent (n = 22) of juveniles survived to >1 year. Juvenile survival was higher in the South and Heritage Agreement patches,and was greater in the wetter year (2010) than in the other years. More juvenile males survived to >1 year of age (n = 16) than did females (n = 6), and survival of juveniles was positively correlated with time spent in their natal territory. Three birds bred at 2 years of age. Scrub-robin survival at Bakara appears to be positively correlated with increased rainfall and higher shrub cover, particularly of Green Tea-tree Leptospermum coriaceum or Hard-leaf Wattle Acacia sclerophylla, as was observed in the South and Heritage Agreement patches.