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.

Sunday 17 June 2018

Why do older male birds father more 'illegitimate' chicks?

Date:  May 31, 2018
Source:  Imperial College London

When female birds have chicks as the result of an extra-marital fling, the fathers are almost always older males, and scientists are finding out why.

Many birds, particularly songbirds like sparrows, form social pair bonds. They usually stick with one partner for life to raise chicks, but may have affairs that result in 'illegitimate' children. From previous studies, it is known that older males are more likely to sire illegitimate children, but exactly why has remained a mystery.

Now, a team of researchers led by Imperial College London have studied the behaviour of a captive population of sparrows at the Silwood Park campus to find out why older males are so successful. Their results are published this week in the current issue of Scientific Reports.

They tested two possibilities: that older males are better at coercing females into extra-pair affairs (the 'male manipulation' hypothesis), or that females solicit more sex from older males than from younger males (the 'female choice' hypothesis).

No comments:

Post a Comment