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, 27 October 2017

Birds without own brood help other birds with parenting, but not selflessly


October 23, 2017

Birds will sometimes care for the offspring of other birds of their own species if they anticipate future benefits. Being tolerated in another bird's territory and the chance to inherit that territory later are considered rewards for which some birds are willing to postpone their own chance of reproduction. On 23 October 2017 veni researcher Sjouke Kingma from the University of Groningen has published an article on this subject in Nature Communications.

In almost 10 percent of bird species around the world, certain individuals postpone their own chance of reproduction to help birds of the same species to care for their offspring. This behaviour has also been observed in certain mammals, fish and insects. Since the days of Charles Darwin, biologists have assumed that all creatures are selfish, and do everything they can to maximize the chance of passing their genes to their offspring. So why do some birds sacrifice themselves for the sake of others? What do they gain by not producing their own brood and wasting energy to help others?

One hypothesis is that they only help their relations, i.e. younger brothers and sisters with whom they share their genes. This is thought to be a way for the helpers to pass on their genes, without reproducing themselves. In a recent study, evolutionary biologist Sjouke Kingma refutes this widely accepted vision by showing that these individuals are also trying to improve their own future prospects. Kingma compared 44 species of birds, some of which help other birds while denying themselves their own brood. Although some birds only help family members, his research showed that a lot of birds are even more keen to help non-family members if they stand to inherit their territory in the future.

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