Can cuckoos trust the surrogates?

20 September 2009

Part of the show Life in the Branches

cuckoo.jpg

The cuckoo, perhaps the best known parasite, is reared by foster parents. After it hatches the chick pushes its adoptive brothers and sisters out of the nest.

Credit:

Question

Just rounding up this whole idea of cuckoos and what they do, it does seem quite extraordinary that you go to such an effort to have babies and you think looking after them is very important and to trust that to another animal seems really quite bizarre, doesn’t really make so much sense. You’re obviously putting a lot of trust in the host animal to look after your babies well, aren’t you?

Answer

We put this to Rebecca Kilner, Department of Zoology, CambridgeYes, that's right. You're leaving them with the responsibility of bringing them up but at the same time you're avoiding all the costs that they incur in rearing children. So, it makes sense that these parasites have evolved.