Multiple individuals incubating and nest building, and winter breeding, in the Black-chinned Honeyeater Melithreptus gularis

Abstract

The role of the male and female in the incubation of eggs is unknown in 30 of the 70 species of Australian honeyeaters, but in most of the remainder, only the female is thought to incubate. Nevertheless, incubation by both male and female is known to occur in six species, including the Brown-headed Honeyeater Melithreptus brevirostris. I observed and video-recorded activities at two nests of one group of four Black-chinned Honeyeaters M. gularis gularis in south-eastern Queensland. Nest attentiveness (incubation constancy) averaged 88% over three sample days. At least two birds participated in incubation, as evidenced by numerous change-overs, strongly suggesting that both male and female were involved. Incubation bouts averaged 7.2 minutes, but varied significantly over the 3 days, and off-bouts averaged 1.3 minutes but did not vary significantly. Nestling provisioning rates varied from 7.5 to 14.4 feeds h-1 on the fourth and thirteenth days after the estimated hatching day. Although cooperative breeding could not be confirmed, up to three birds were seen at this nest during the nestling stage, and up to three at the second nest before incubation began. Breeding records indicate that in south-eastern Queensland laying peaks in winter, beginning in late autumn, 2 months earlier than records suggest in New South Wales.