Nesting Biology of the Golden Bowerbird Prionodura newtoniana Endemic to Australian Upland Tropical Rainforest
1998
Frith, Clifford B. | Frith, Dawn W.
Golden Bowerbirds Prionodura newtoniana nests (n = 86) were studied on the Paluma Range, north Queensland during 1978–89. Nesting began in late October; 93% of clutches were incubated during November-January and 64% of fledglings left the nest in January. Breeding failed in one season, apparently due to lack of food. Nests were deep, bulky, open cups typically built within a ‘roofed’ vertical crevice in a tree trunk (63%) or in a crevice-like site, mostly < 3 m above ground. Several nesting locations or specific nest sites were used more than once, sometimes by the same female. Nest sites averaged 97 m from a bower actively attended by an adult male. Nests took up to 25 days to construct and were laid in from 3–28 days after completion. Of 26 clutches, 65% were of two eggs and 35% of one (mean 1.7). At laying an egg was 13.6% of mean adult female weight. Only one female incubated, brooded and fed young at each nest. Eggs were incubated for 21–23 days in bouts averaging 18 min at 1.8 bouts per h. Nestling period was 17–20 days. During the first 13 days of nestling life, females spent 13% less time brooding two nestlings than one. A mean of 3.3 meals per h was provided for one nestling and 5.9 for two; of 408 identified meals, 68% were fruit and the rest animal, mainly insects. Nearly half the fruit meals were of four species of Elaeocarpaceae and > 45% of insect meals was cicadas; more fruit was fed to older nestlings. One to three days before nest departure mean nestling weight was 75% and mean wing length 52% that of adults. Fifty-six per cent of eggs hatched and 58% of nestlings fledged; 34% of eggs produced fledglings and overall nest success was 28%. Females produced 0.5 fledglings per year. We compare these data with those for three other bowerbird species.
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