Helen Scales asked:
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, doesnít really make so much sense. Youíre obviously putting a lot of trust in the host animal to look after your babies well, arenít you?
We put this to Rebecca Kilner, Department of Zoology, Cambridge
Yes, thatís right. Youíre leaving them with the responsibility of bringing them up but at the same time youíre avoiding all the costs that they incur in rearing children. So, it makes sense that these parasites have evolved.