Horsfield’s bronze cuckoo has some behaviours that can only be described as cuckoo! Photo: Chris Tzaros.
Photo by
Chris Tzaros
The metallic colour on the Horsfield’s bronze cuckoo and common bronzewing might be one of the pair’s only things in common.
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That, and the fact they’re both birds.
The bronze cuckoo sneakily abandons her baby’s egg in another unsuspecting expectant mother bird’s nest and hot wings it out of Dodge, while the bronzewing lovingly incubates her eggs with the unwavering support of her mate.
Both mother and father bronzewings stick around to raise their chicks and, fascinatingly, both produce crop milk — a milky substance regurgitated from the ‘crop’ (an enlarged part of the oesophagus) — to feed their young.
This year, the Goulburn Broken Catchment Management Authority celebrates birds and bats in a ‘Year of the Wing’ community awareness campaign.
The Horsfield’s bronze cuckoo and the common bronzewing are August’s feature species.
GBCMA project officer Janice Mentiplay-Smith said the Goulburn Broken catchment was home to these two commonly seen bronze birds.
“The Horsfield’s bronze cuckoo is a species of cuckoo that inhabits Goulburn Broken catchment woodlands, rural and urban areas, where it shimmers and shines in the sunlight as it takes to the air in search of a caterpillar dinner,” Ms Mentiplay-Smith said.
“Interestingly, the bronze cuckoo is known as a ‘brood parasite’, meaning when it comes to nest construction, it opts to take advantage of the hard work of others.
“When the coast is clear, the female darts to her chosen nest — often that of a superb fairy wren or thornbill — and in a few fast seconds lays her single egg.
“She departs just as quickly, before the guileless homeowners return. Before leaving she may even eject one of the other birds eggs to maintain the status quo.”
Ms Mentiplay-Smith said the unsuspecting host parents incubated the imposter egg, which hatched within 12 days, usually ahead of the other eggs, ensuring the imposter chick received its unsuspecting host parent’s undivided attention.
“Like its biological parents, the newly hatched Horsfield’s bronze cuckoo chick is hard-wired for survival and may eject other eggs or chicks from the nest to eliminate the competition.”
The common bronzewing is a family-oriented species of pigeon found in various habitats across Australia. Photo: Chris Tzaros.
Photo by
Chris Tzaros
Ms Mentiplay-Smith said the other bronze bird featured, the common bronzewing, was a member of the pigeon family.
It lives in various habitats across Australia and has successfully adapted to life in agricultural areas.
“Known for its mournful, repetitive ‘whooo-whoo’ call, the ‘bronzie’ is a beautiful bird; its gleaming metallic wing patches catch the light as it scours the ground for seeds and small pieces of vegetation,” Ms Mentiplay-Smith said.
She said the easily startled bird, which was always on high alert, primarily ate wattle seeds, which highlighted the importance of a healthy, shrubby understorey.
Since its dry diet is not supplemented with moisture-laden insects, it stays near water.
“Both bronzewing parents incubate the eggs and care for the chicks. Interestingly, they produce crop milk to feed their young,” Ms Mentiplay-Smith said.
“Crop milk, also known as pigeon milk, is produced by both sexes of all species of pigeon.”
If you’re interested in seeing the two bronze bird species in their native Goulburn Broken catchment environment, you can join a bird survey with Murray Goulburn BirdLife group at Mount Piper, Broadford, on Saturday, August 17.