Let’s talk about mafia behavior in cowbirds.
When a bird raises a cowbird baby, their biological children sometimes don’t do too well. In species that are much smaller than the cowbird, the parents are so excited about their cowbird baby they forget to feed their other children. And in some species of cowbird, the fledglings can be mean to their non-cowbird siblings, going so far as to eject them from the next. And even when neither of these things happen, the host parent uses a lot of energy raising this kid with no real evolutionary benefit.
Hosts, therefore, are bound to evolve strategies where they reject cowbird eggs and fledglings.
To keep this from happening, cowbirds sometimes retaliate against birds that don’t accept their eggs. They will ruin their nests and make sure they don’t get to breed that year. In that situation, the hosts that take on the cowbird babies do a lot better.
I’ve been portraying cowbirds in kind of a rosy light, but I thought it would be good for you to know that they can be real jerks sometimes.
ANYWAY, here’s a video of two male cowbirds competing over the same female. It’s adorable.