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.

Monday, 22 June 2015

Vagrant bachelors could save rare bird

Date: June 16, 2015

Source: Zoological Society of London

Summary: A study has revealed the importance of single males in small, threatened populations. Results from a study of endangered New Zealand hihi birds shows that bachelor males who don't hold breeding territories, known as 'floaters,' could help maintain genetic diversity and decrease the likelihood of inbreeding by sneakily fathering chicks.

These underestimated individuals are vital to the long-term survival of small populations, such as in the hihi, a rare bird found only in New Zealand. There are thought to be only 2,000 individuals left in the wild, making them extremely vulnerable to natural disasters or disease, of which a single severe incident could wipe out the whole species.

While floaters have much lower breeding success rates than coupled males, in hihis they are able coerce females, which are already coupled up, into mating. This has been shown to have a small but significant impact on population size by increasing the number of breeding birds, as well as influencing the sex ratio. These factors are important in maintaining genetic diversity and decreasing levels of inbreeding.

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