Article kindly provided by Jim Clark.
Life in the Bush
I have seen the Chestnut-breasted Munia (Lonchura castaneothorax) many times in the wild, both locally and nationally. Thirty years ago in the Kimberley’s, I came across them along the creeks and rivers of the Mitchell Plateau, WA usually in shady Pandanus draped out over the water. In recent years, I have seen them on the North Coast in valleys behind Coffs Harbour, NSW, again sitting quietly in groups amongst Blackberry and Lantana growing beside farm roads. They know how to stay cool in the heat and deliberately sit out of the sun.
Locally I’ve found them breeding in summer, on farmland behind Penrith’s Beef and Barramundi Restaurant, and also at the duck ponds at the western end of Richmond, NSW. Both breeding locations are over, near, or in, water. In winter, I have watched them in large numbers feeding on cut grass lawns along Correen Ave, Penrith, NSW, hopping along the ground mixed in between Red-Rumped Parrots. They were eating the Winter Grass seed heads. At my workplace at Eastern Creek, NSW, they seem to have been replaced by the Spice Finch in recent years.
My own observations show them to be very social, flock bird. They stick together and fly as a flock, twisting in flight like Starlings when they fly quiet high and fast. Whilst their slower flight is just the usual finch “bobbing” style. In NSW they seem to be sedentary or locally migratory dependant on food supply and breed according to seasonal conditions.
During the spring, in Eastern Australia they seem to spread out to breed, so you only see pair’s or small groups. In Autumn I’ve seen dozens of mixed young and old birds in flocks near the Penrith Sewage Plant, when the numbers appear to peak.
Then they obviously diminish during winter, back I suppose, to the base population numbers for the start of the next Spring breeding. In summer they are more easily observed because they land on top of the long grass heads.
No roosting nests are made by Chestnuts; they sleep in trees or reeds. Nests are only built for breeding purposes and pair bond is strong at this time and weaker in the non-breeding period.
In late afternoon, they return to their roosting place. In my experience this is always near water.
Life in Captivity
They are a strong, hardy bird. Often long lived (3-4 years). Quite capable of vigorously defending themselves and their nest or young, although most times they are inoffensive aviary members and mix well with other finches. My birds seem to produce around 5 to 6 young each year, enough to maintain my 2-3 pairs and sell or give some away. They dislike nest interference, so I leave their nest alone. I find them easy and reliable parents in my larger colony aviary, which is 7 metres by 3 metres and about 2.1 high.
A breeding diet of finch-mix, plus a few mealworms and some seeding grass is sufficient for them to rear their young. Sometimes the young birds are clumsy for a few days if they leave the nest a little early, not quite feathered, usually with some down still showing on the side of the head.
Incidentally the young birds take several months to fully colour up, perhaps six months. With full colour attained after a “mottle look” that seems almost permanent. Other Munia type birds also takes a similarly long period, perhaps up to nine months for Gouldians and Nuns. I see this as a defence mechanism that gives the immatures a chance in the wild. For instance, during my two years work in the top-end of the Kimberley’s I rarely saw a mature Gouldian.
In an aviary they are a bird that flies strongly and pairs often fly together following each other along the length of the flight. When the Spring daylight hours increase the males song appears more often and he eventually pursues the hen vigorously around the flight. I’ve been concerned at times because it looks dangerous, but then breeding seems to start soon after with nest building occurring. This mock aggression may simply be laying down the law, or a preliminary part of the Lonchura display ritual. When you see this behaviour it means they are going to breed, or at least make an attempt.
The resulting nest is a strong circular affair with a side hole and not entrance tunnel. Very few feathers are used just soft lining grass. My chestnuts have been closely inbred over 15 years, so they only lay around 4-5 eggs and raise 2 to 4 young per nest. They build a natural nest in dry brush inside a corrugated iron shelter shed and generally high up. Around 6 to 8 feet high.
By choice they like fresher greener grass to build with, but mine seem to make do with a mix of dry and green. Newly fledged Chestnuts are awkward but soon learn to eat and drink. They are deserted by their parents at about two weeks out of the nest so they either make it or not right then. The parents just refuse to feed them, even if they beg.
I haven’t attempted to breed them in a cage, since my birds are quite wild in a big aviary. I think it could be difficult. Equally I’ve always let them pair up themselves, avoiding the difficulty of picking a truer pair.
Life in the Future
No doubt in 100 or 200 years from now Australians will have developed this country towards the limits of population density and land use. And if current trends prevail then obviously during this process many extinctions will occur in our Animal and Birds species. However this bird has a large distribution along the waterways and grassy edges in Eastern and Northern Australia, in areas not usually frequented by large numbers of people. So I expect them to remain a viable finch species.
I think both the lifestyles and strength of the Chestnut Finch species will combine with its massive distribution to ensure its survival, particularly in the North West of Western Australia. However it will probably diminish in numbers due to habitat loss, and as a result of both human and introduced bird competition it will become scarcer.
Presumably this will increase its value, which paradoxically will result in the bird being appreciated more than its today.
I think this “economic interest” will decide the future for a large number of our native finches, perhaps ensuring their true and ultimate survival in both captivity and the Bush.
As an inside we should recognise that this species is also represented overseas, with several sub-species existing in New Guinea. It was also introduced on several large Pacific Islands prior to the war in the Pacific with some early success, although I’m uncertain of the success of current populations.
In conclusion, I can see colour mutations being an impetus to its avicultural survival, as they are in other Finch species. Last Christmas, in a nest of three young birds, I bred a dilute Fawn Chestnut Finch. It is now a fully coloured male. So it appears to be a recessive mutation and is quite attractive with its soft colours. The face is light grey, as is the bar, while the head, breast and wings are soft fawn. His most vibrant colour is on the rump, a bright golden yellow.
I have the parents who are now quite old and also two pairs of sibling brothers and sisters, all in one aviary. Hopefully next spring will see some more of his kind.
Based on many years association with this species, I can recommend this finch to all dedicated aviculturists. They are hardy, mix well with other finches and are relatively easy to breed. I have one serious word of warning though, don’t mix them with other Munia species or you may find some strange coloured young hybrids flying in your aviary.