Stewart Island myth

[lloydesler]

Hi folks, there is a bit of a persistent story that the kiwi and kakapo are relatively recent introductions to Stewart Island ie: in European times, the result of a liberation following a shipwreck, the birds having been destined for a zoo somewhere. Has anyone looked at this? What evidence is there for the truth of story or evidence of the presence of these birds going back beyond 150 years? Thanks
Lloyd Esler

[Paynterq]

Hi Lloyd

The myth is certainly busted for kiwi/tokoeka as the the Stewart Island Population has been shown to be genetically distinct from the Fiordland populations.

I'm not sure if this publication has free access https://www.pnas.org/doi/10.1073/pnas.1603795113 (Full reference: Weir, J. T., Haddrath, O., Robertson, H. A., Colbourne, R. M., & Baker, A. J. (2016). Explosive ice age diversification of kiwi. Proceedings of the National Academy of Sciences, 113(38), E5580-E5587.)

It states: "Our dating suggests that Stewart Island, Haast, the extinct Mount Somers lineage, and an ancestral Fiordland lineage diverged two or three glacial cycles ago, followed by subsequent divergence of the Fiordland region into North and South Fiordland populations, probably during the last one or two glacial advances."

Cheers,

Quentin

[Jim_j]

Hi Lloyd
I have read a paper on this recently (sorry I just can't remember where - maybe on the DoC Kakapo website?).
They have traced the DNA separation back to when there was a land bridge between the South and Stewart Is - so any Kakapo that were from any shipwreck don't appear to have contributed to the current Stewart Is gene pool.

Cheers
Jim

[Handa457]

Hey Lloyd while the Kakapo population does appear to be descended from a land bridge a recent study released by kakapo team looking at the species genome does identify that two birds Barnard and Jean have significantly more alleles found in no other bird than the rest of the population.

My understanding is Richard Henry had about 20% of his alleles found in no other bird. While Jean and Barnard sit around the 8 - 10% mark. Does that mean that they're descended from shipwreck birds? Hard to say as I'm not an expert. Kakapo probably have undergone a second genetic bottleneck in last few generations as population was predated on Stewart island. But you'd expect birds from remote locations to be the most genetically distinct. Interestingly Piripi who was discovered sixteen kilometres away from any other bird was not particularly genetically isolated from them. So Shipwreck theory might have some merit for Jean and Barnard. But again. Not enough of an expert to do anything other than speculate.

[Neil Fitzgerald]

To clarify for people who might not be familiar with kakapo and misunderstand this thread; there are no longer any kākāpō on Rakiura / Stewart Island. This thread is discussing the origin of birds from Stewart Is that were transferred to other islands.

[Ian Southey]

https://www.birdsnz.org.nz/wp-content/u ... s_10_2.pdf - look on page 25. I think there may be another source but I don't remember enough to find it off hand.

Ian