Genetic Bottleneck Threatens New Zealand’s Iconic Little Spotted Kiwi

The Little Spotted Kiwi was once the most abundant species of kiwi in New Zealand, but the introduction of invasive species and anthropological activities have changed their fate forever.

Kiwi’s are flightless, nocturnal birds native to New Zealand. The Little Spotted Kiwi (Apteryx owenii) was once the most common of the five kiwi species. Due to the introduction of invasive species, habitat fragmentation, and a flourishing skin trade, their numbers declined and by 1980 they were listed as extinct on the North and South Islands of New Zealand.

A Little Spotted Kiwi foraging in the brush. Credit: Kimberley Collins

In 1912, conservationists noticed their decline and introduced five individuals to Kapiti Island. These five kiwis were the last remnants of their species, suffering what scientists consider a severe genetic bottleneck. A genetic bottleneck is when a population is reduced to such low numbers that the genetic diversity of the species is compromised, making them more susceptible to diseases and other threats.

Because the little spotted kiwi passed through a severe bottleneck, it has the lowest genetic diversity of the five kiwi species and among the lowest recorded genetic diversity of all birds.”  

Kate Guthrie, Predator Free NZ

Miraculously, the after their introduction to Kapiti, the birds flourished and were able to produce what is now a population of 1200 individuals. The new generation of kiwis were grouped in pairs and placed on different islands in order to preserve these vulnerable birds and continue to allow them to reproduce. However, since their translocation, conservationists have noticed significant genetic erosion from the generations produced after those five individuals.  

A Little Spotted Kiwi searching for food. Credit: 360 Discovery Cruises

For example, samples taken from island-bred birds on Tiritiri Matangi Island up to 2012 showed a 12% loss of alleles per locus and a 4% loss of heterozygosity relative to the Kapiti Island population.” 

Kate Guthrie, Predator Free NZ

The kiwis of Tiritiri Matangi Island are more vulnerable to new challenges, such as exposure to a new disease or environmental change. Specifically, severe droughts induced by climate change have had the greatest effect.  

Presently, conservationists are making every effort to improve the genetic diversity of all populations of Little Spotted Kiwi. With a new research survey underway to investigate how inbreeding will affect the species and translocating individuals of each population, hopefully, the longevity of the Little Spotted Kiwis will be ensured.

Featured photo: Little Spotted Kiwi. Credit: Judi Lapsley Miller
Source: Predator Free New Zealand

About Nicholas Scott

Nick is an undergraduate Marine Biology student at the University of California, Santa Cruz. Having spent his life exploring the ocean on California’s coast, he developed a passion and respect for it, that demanded him to pursue his interest in conservation. Volunteering for the communications team allows him to further his interests and gain more insight as to how to resolve the state of the world around us. In his spare time, Nick enjoys surfing, swimming, and spending time with friends.

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