Pied Currawongs arriving in the
Clarence Valley each autumn and winter is a natural event, but recently their
numbers have been increasing. They are also hanging around longer, with dire consequences
for our smaller native birds.
Currawongs look like crows,
but with white undertail and wing feathers in flight. Mainly they inhabit the
Ranges, living on fruit, insects and lizards in the forested gullies But in the
colder months when food becomes scarce, they flock and head to the coast, where
exotic park and garden trees, garbage bins, and growing numbers of fruit farms keep
them supplied until spring when they return home to breed.
Currawongs' beaks are ferocious
weapons, once known for piercing foil lids on the early morning milk delivery,
but now turned on late winter-nesting birds' eggs and chicks, and even the
birds themselves. Small migratory birds like the Silvereye, which travels greater
distances than any bird of its size, now competes with big Currawongs for fruit,
but frequently becomes the lunch.
Currawongs can pick off red
bull-ants, and even one or two toxic spit-fire grubs without ill effect, so defenceless
little birds and their offspring become tender morsels, with more taken as the
predators increase.
Where currawongs stay longer they can also breed, and have
been found feeding their own chicks on flesh torn from threatened adult Gould's
Petrel.
A study of regurgitation
pellets by the Australian National University showed that while all leavings contained
fruits and seeds, almost half contained remains of birds. In another study by
the Australian Museum, fake Willy Wagtail eggs that retained beak and teeth
imprints showed 64% of nests were attacked, with 63% of those by birds with
large bills. In 134 situations currawongs were actually seen attacking the
eggs.
It is also found that
currawongs target the fruit of invasive privet, which massive effort and large
sums of taxpayer funds finds virtually impossible to eradicate.
It could in the end be up to individual
landowners to discourage these birds, to force them to stay comfortably in the
ranges where they naturally belong.
- Patricia Edwards
This article was originally published in the VOICES FOR THE EARTH column in The Daily Examiner on November 26, 2018.
