Nest, egg and vocalisations of the Green-backed Robin <em>Pachycephalopsis hattamensis</em> in the Arfak Mountains, West Papua

Abstract

The Green-backed Robin Pachycephalopsis hattamensis is a near-endemic species of Papua (Indonesian New Guinea; Irian Jaya). Its breeding behaviour is poorly known, and its nest, egg and clutch-size were unknown prior to our study. We describe the nest and egg of a Green-backed Robin found near Kwau village in the Arfak Mountains, Papua, in mid-November 2012. A second nest with one young in late January 2012 confirms that the breeding season occurs during the wet season, at least from November to January, in the Arfak Mountains. The nest and egg are similar to those reported for the congeneric White-eyed Robin P. poliosoma in Papua New Guinea, and both species may have clutch-size of one. In our study area, the most frequent and persistent vocalisations of the Green-backed Robin, depicted in two spectrograms, were tu-wee sounds, uttered by both sexes. Other vocalisations heard were a piping whistle and a raspy chur-chatter. The function of these vocalisations is discussed and compared with other Australasian robins. We also describe interactions between the sexes and neighbours.