A study by the Zoological Society of London (ZSL) has found that bachelors don’t always need to be one the lookout for love. In small, threatened populations bachelors help to decrease the likelihood of inbreeding within populations.
Published in Evolutionary Applications the study has found that in populations of the endangered New Zealand hihi birds single males known as ‘floaters’ due to not holding a territory can help to increase genetic diversity and reduce inbreeding rates by sneakily fathering chicks.
Lead author of the paper, Dr Patricia Brekke said, “Conservation management often discounts individuals that are thought to be unable to produce offspring, thinking that they have no effect on populations. We have shown that in hihi, floaters are able to reproduce and pass on their genes from one generation to the next, which helps with long-term survival of this endangered bird.”
“Despite being difficult to study, as they have no fixed abode, we should pay more attention to these bachelor males as they can potentially have a big effect on genetic diversity and therefore the survival of species with very few individuals remaining. Not taking floating individuals into account can undermine our conservation efforts,” added Brekke.
This rare bird numbers just 2,000 individuals in the wild who are restricted to one island off New Zealand. They were lost from the North Island during 1895 as predators were introduced and habitat loss due to farming. One natural disaster of disease could mean disaster for this species.
In New Zealand ZSL has reintroduced this species to five places but the colonies remain small with just 150 members or less in each. Conservation efforts have been ongoing since the 1980s.
ZSL has identified this bird as evolutionary unique being its own family. They are also the world’s only animal other than humans which mates face to face.
Floaters have less breeding success than territorial males but they are able to mate to with coupled females. This helps to increase genetic diversity and influences the sex ratio. Floating is a technique used by mammals, fish and insects. It saves energy and helps young males who cannot yet defend a territory or older males who do not have the energy to do so.
Photo Credit: By Duncan Wright (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 4.0-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/4.0-3.0-2.5-2.0-1.0)], via Wikimedia Commons