Over at Nothing in Biology Makes Sense!, Amy Dapper discusses a new study of brood parasites, birds that lay their eggs in the nests of other bird species, letting those adoptive hosts take on the costs of raising the brood parasites’ chicks. This sounds like a bad deal for the host species, but in at least one case, it turns out that a brood parasite chick can be a boon to its adoptive nest-mates:
Canestrari et al. (2014) focused on the great spotted cuckoo (Clamator glandarius) and their host, carrion crows (Corvus corone corone). They studied the success rate of nests with and without brood parasitism and found that carrion crow nests that contained parasitic cuckoo nestlings were actually more likely to be successful (i.e. fledge at least one crow nestling). How could this be?
To learn why a carrion crow might want to raise a baby cuckoo, go read the whole thing.◼