NEST PREDATION IN AUSTRALIAN URBAN ENVIRONMENTS AND THE ROLE OF THE PIED CURRAWONG, STREPERA-GRACULINA

An experiment, involving 2000 members of the public, determined the id entity of nest predators in urban environments. Experimental nests of halved tennis balls covered with coconut fibre and wool were manufactu red to resemble the nests of willie wagtails, Rhipidura leucophrys. Th e identity of predators was determined by analysis of imprints left in artificial eggs made of coloured modelling clay. Sixty-four per cent of nests were preyed upon, with most predation being the result of lar ge birds. Direct observations of predation (n = 134) indicated that pi ed currawongs were the most common large bird, accounting for 52% of a ll predation. Predation incidence was higher in gardens with more tree s and in which kookaburras, Dacelo novaeguineae, were fed frequently A mong nests placed in trees, nest predation was correlated with nest he ight. Eggs camouflaged by speckling experienced a similar incidence of predation to plain eggs. This study provides evidence to support the contention that pied currawongs are a major threat to the persistence of small birds in Australian urban environments.