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.

Wednesday, 8 March 2017

Birds of a feather mob together




Group mobbing behavior gives male birds the chance to impress potential mating partners

Date: February 22, 2017
Source: Springer

Dive bombing a much larger bird isn't just a courageous act by often smaller bird species to keep predators at bay. It also gives male birds the chance to show off their physical qualities in order to impress females. This is according to a study in Springer's journal Behavioral Ecology and Sociobiology on predator mobbing behavior of birds where potential prey approach and harass would-be predators such as owls. The study was led by Filipe Cunha of the University of Zurich in Switzerland and the Federal University of Ouro Preto in Brazil.

In birds, mobbing behavior includes calls, aerial swoops and even physical attacks. For a long time, researchers believed that this behavior mainly served as protection against predators, since most predators move away in response to mobbing.

As an added bonus, mobbing might give males the chance to advertise who has the best physical qualities, in an effort to impress potential mating partners. To investigate this further, Cunha and his fellow researchers studied what happened when replicas of two types of owls of similar size were presented to a bird community in south-eastern Brazil. The models were of a pygmy owl that regularly eats birds, and of a less threatening burrowing owl. The researchers measured the size of the mob that then assembled, the intensity by which individual members participated in the mock attacks, and whether things changed if females from the same species were present.

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