In keeping a local nature diary and coming up with subjects for this column, it’s a bit hard to go past the arrival of our spring migratory birds at the moment.
We have featured a few of these in recent weeks and are likely to continue on this theme as the candidates keep rolling in.
This week, we have noticed the arrival of Shining Bronze-cuckoos in our region.
This species occurs in eastern Australia and further afield into Papua New Guinea, so some of our recent arrivals might have travelled extraordinary distances to get here.
Most years, they start to arrive in August but it is not until September and early October that we see our biggest numbers.
Their occurrence in any given year varies; in some years they are particularly common yet in others they are scarce, perhaps choosing to visit a completely different region.
Upon their arrival, they give their very distinctive and at times monotonous calls, which is often the best way to locate them, as they are typically quite shy and rather hard to see.
As the breeding season approaches, males can sing persistently from a favourite perch, day and night, especially on moonlit nights.
Their call is a plaintive, mournful whistle, similar to their relative the Horsfield’s Bronze-cuckoos, yet there are key differences between the two that allow them to be readily identified.
The call of the Horsfield’s Bronze-cuckoo is a descending ‘tseeeeuw, tseeeeuw’ repeated many times, but they also give a high-pitched chirruping call as well.
The main call of the Shining Bronze-cuckoo is a series of high-pitched whistled notes that rise (as opposed to fall) in sequence before ending with a descending note.
As with all cuckoos, bronze-cuckoos are insect eaters and they feed primarily feed on hairy caterpillars gleaned from the ground, from grasses and herbs, and shrub and tree foliage.
It is characteristic behaviour of cuckoos to patiently sit and wait while scanning nearby vegetation for any signs of caterpillar activity.
Upon seeing a prey item, they pounce on it from above and immediately bash it on the ground, a nearby rock or branch, to kill the caterpillar quickly before potentially being stung (by species species such as Cup Moth Caterpillars).
Again, like all cuckoos, Shining Bronze-cuckoos are nest parasites relying on a host species to rear their young.
They select small insect-eating bird species as their hosts, typically those that build dome-shaped nests such as fairy-wrens, thornbills and gerygones, but also some open cup-shaped nesters as well, such as robins and honeyeaters.
The cuckoo lays its egg in the nest and removes one of the host’s eggs.
The cuckoo's egg is the first to hatch, after which it instinctively forces the other eggs and chicks out of the nest.
The cuckoo chick then receives the sole attention and care of its ‘foster parents’ until it leaves the nest and for a period thereafter until it is independent.