According to research published today in Biological Letters, the idea of nepotism and favoritism toward children doesn't stop with humans. An African desert-dwelling bird favors his biological sons and alienates those that are his stepsons.
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"Nepotism has likely played a vital role in the evolution of family life in this species," said Martha Nelson-Flower, who is a postdoctoral fellow at the University of British Columbia's faculty of forestry. She performed the researcher at the University of Cape Town, according to Eureka Science Alerts.
The birds she studied were a black and white bird found in Botswana, South Africa, Namibia, and Zimbabwe. The southern pied babbler lives in groups with chicks raised by both parents as well as some other adults. The groups range in size from only three birds to up to fourteen.
The group's dominant male bird decides which of the subordinate males that he likes in the group. Nelson-Flower's research then shows that the subordinate birds spend less time within the group if they aren't related to the dominant male bird. These subordinate male birds are then pushed out of the group by their stepdads, or in some cases, a brother in law. They are then forced to join other groups or go it alone.
Nelson-Flower's research lasted over five years. She observed 45 different groups of southern pied babblers within the Kalahari Desert. She completed her study by walking around with the birds at dusk and dawn. Her study also used data collected by Amanda Ridley of the University of Western Australia, her co-author.
Interestingly enough, the preferential treatment that the male birds showed was not seen in the females.
"The research is some of the first to show that the sex of both dominant and subordinate birds, and the genetic relationship between them, has a significant impact on their family groups and cooperative breeding behaviour," said Nelson-Flower.