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These beautiful birds were first sighted on Curacao a little over a decade ago. The response of one of our colleagues, who was fast to identify the species, was a frantic hunting party. Armed with an air gun he shot several birds. What was going on?
These birds, identified as Shiny Cowbirds (Molothrus bonariensis), display the same reproductive behavior as the common cuckoo in Europe. These birds are brood parasites, which means they will not build a nest themselves, but simply lay an egg in a nest of another bird. After hatching, the chick will push the other eggs or hatchlings out of the nest. The unfortunate parents don’t have a clue and will raise the invader as if it is their own chick. Such behavior can be extremely damaging to an ecology that has not evolved a level of defense against it. Hence the actions of our colleague.
How these birds ended up on Curacao we don’t know. That their nest parasitism is effective has unfortunately been observed. Several years ago we encountered a Trupial Kachó (Yellow Oriole – Icterus nigrogularis) in the process of raising a black chick. Not good.
On the other hand, we have not seen these birds as often as feared. Maybe the environmental harshness interferes with their survival skills. Let’s hope so.