Choughs eat mainly invertebrates: spiders, caterpillars, centipedes, beetles which they probe and glean from the soil, leaf litter, bark and low shrubby vegetation. They also eat orchid tubers. A family group is a minimum size of four, and up to 10.

In the early 1970s, bird researcher Merle Baldwin studied the way choughs search for food on the forest floor, and it is completely mathematical in its precision: "One feeding circle, described as 180m in diameter, involved 30 birds in four breeding groups. Birds moved in irregular lines of 6-8 birds in small anti-clockwise circles within a larger clockwise circle; small circles overlap leaving no ground uncovered. Four large feeding circles were completed each day."

Furthermore, these foraging circles differ when the choughs are nesting. "When a group begins building a nest, anti-clockwise movements inside a larger foraging circle become confined to within 90m of the territory boundary, leaving ~180m around the nest untouched, which later provided a food source for the nestlings."

Our property, with a compost heap, leftover bird seed from the aviary and complex garden environment, provides a rich source of food for the young birds. Now it's winter, they have moved away from their small nesting territory and range widely over the surrounding properties and state forest.

The family group is essential. I have seen a lone chough on just one occasion. Unlike most social bird species, choughs never disperse as solo birds. When a family group becomes large, over 12 individuals, they may break up into smaller groups that disperse and reform with birds from other groups.

Choughs are known as co-operative breeders, where young from previous years stick around and help the parents raise the new generation. In kookaburras and fairy-wrens this is the usual way of breeding, but if need be, they can raise young just as a pair. With choughs, they must have a family group, otherwise they do not breed.

All members of the group help to build the mud nest, brood the eggs and feed the nestlings. The young fledgelings are particularly vulnerable to foxes and cats when they leave the nest, as they cannot fly, only clamber of trees while their family members scream encouragement at them. After 28 days, the young can fly as well as the parents.

The nestlings take a very long time to reach sexual maturity: a whole four years.

Larger family groups have better chance of raising chicks successfully, as they are able to fend of predators such as currawongs, find more food, and establish the richest feeding territories. There is such an advantage in numbers that choughs will steal young birds from other family groups.

The new BirdLife Castlemaine District group is visiting Tipperary Springs for a bird walk from 9am-noon on Saturday, July 6. Beginners are welcome.