The hihi, an endangered bird species native to New Zealand, might have better survival chances than previously thought. Currently, there are only about 2,000 individuals left in a species that is the only one of its family, and unique among birds. The species has been decimated by the introduction of new predators like rats, the conversion of land for agriculture, and disease. In fact, since the population is so small, disease is a big concern for naturalists, as something particularly virulent could easily wipe out the population.
Attempts to help the species survive are under way, but one thing that naturalists can’t do much about is a lack of genetic diversity. Inbreeding is a significant concern, but according to a recent study by the Zoological Society of London, it’s not quite as big a concern, thanks to “floaters” in the male population.
Floaters are single males, who do not have stable mates and don’t control any territory of their own. Most male hihi protect a territory from other males, mate with one female, and work to help raise their chicks. These “floaters” are often young birds that are inexperienced in defending territory, or older males who don’t have the energy to protect territory or raise chicks. So they move around, occasionally convincing a female to mate with them, and help preserve genetic diversity.
Previously, such “floater” males, found among bird, mammals, insects, and fish, have been written off as not adding to the population, since it was assumed that they largely didn’t produce offspring. This new study finds that they do, in fact, produce numerous offspring, and that their moving around means they reproduce in a much wider range than do more stable pairings. Doing so introduces new genes into regions, which keeps the gene pool from getting too shallow.