A local gentleman rang the Sanctuary recently to tell us about a bird that has been eating Cairns Birdwing butterfly caterpillars off the vine that grows in his garden. This was interesting, as Cairns Birdwing caterpillars and butterflies are poisonous for birds to eat.
The gentleman has watched the bird come and systematically search the vine for caterpillars and on occasion, it has brought friends. The bird identified is an Olive-backed Oriole and it’s not the first time I have heard about this bird eating Birdwing caterpillars.
The bird should have become quite sick and learned through experience to leave them alone, but obviously this is not the case.
A similar situation with the Monarch Butterflies, who are also poisonous, has been documented in Mexico where the Monarch butterflies spend the winter, hibernating. There are two species of birds and one species of mouse in Mexico that eat the hibernating Monarchs. One of the birds is an Oriole too, but a Black-backed Oriole.
Whether the bird can tolerate the toxins or perhaps it has learnt an antidote, we don’t know.
Photo: C Hunt
Information about Monarch Butterfly: https://www.learner.org/jnorth/tm/monarch/Predation.html