As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday, 15 March 2019

Put eggs all in one basket, or spread them around? Birds know best

Date:  February 27, 2019
Source:  Princeton University
In the tropical jungle of Central America where predators abound, a species of cuckoo has found safety in numbers by building communal nests guarded by two or three breeding pairs.
Why then do these agreeable avians sometimes ditch the collaborative lifestyle and instead deposit eggs into nests outside the communal group, acting like social parasites, in the hopes that other females will raise the chicks as their own?
In a paper published online in the journal Nature, Princeton researchers show that the cuckoos, known as greater anis (Crotophaga major), act collectively for the most part but can become social parasites after their communal nest is destroyed. They start the breeding season placing all their eggs in one basket, but if predators intervene, the birds switch to a strategy of spreading the eggs around in other nests.

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