Small population of takahe on European arrival

[Neil Fitzgerald]

A new paper in Ibis:
http://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

I haven't read it all, yet. But basically, takahe were probably common in parts of South Island until Maori hunted most populations to extinction, leaving a population in Fiordland, where they were never common, of similar size to that present today. This is in contrast to many other Fiordland birds that didn't really bomb out until European arrival.

Has Fiordland reached its potential for Takahe?

[Ian Southey]

I can't access the paper so I have to guess which specimens were sampled but I'm assuming they were the first one from Resolution Island, the second from Secretary Island and the fourth from Lake Te Anau. Also available from this time are some bones collected by Richard Henry at Lake Te Anau and the third specimen from the Mararoa River. Ancient DNA from older bones throughout the former range might have better illuminated this issue too.

It is interesting that two of these specimens come from islands and probably would have had limited diversty any way (these birds are flightless). Of the other material the Mararoa skin (which I saw in the Dresden Museum a few years ago so it does exist in spite of rumours) would have been the most interesting as it is very distant from the others and from a dry scrubby habitat. On the other hand, if these are not impediments to their conclusions, then maybe lower levels of genetic diversity are natural and might not so important for NZ bird conservation as some people seem to be thinking at present.

It also depends on what evidence you are prepared to accept but Brian Reid gathered together many reports that suggested Takahe were much more widely spread being eaten by prospectors in South Westland, and even still found in the north west Nelson area in the 1800s. Before the official rediscovery there were reports from almost the full length of Fiordland too so the restiction to the Murchison Mountains is relatively recent.

Neil, I'm not convinced that Fiordland has the best Takahe habitat so much as the best balance between between their needs and problems. Maybe effective stoat and deer control would let them thrive on better soils further east but I don't see Bill English offering up the funding to make it possible in a hurry.

Ian

[Steps]

.....then maybe lower levels of genetic diversity are natural and might not so important for NZ bird conservation as some people seem to be thinking at present

Is it not stange not much or any consideration is given to private breeders experiance and practice in these matters....breeding 'exteme' mutations in all animals...a classic id gold fish and koi over the lat few 1000 yrs, budgies and finches...even dogs and cats to some extent.

[Neil Fitzgerald]

I can't access the paper so I have to guess which specimens were sampled

Grueber and Jamieson:

This study uses samples taken from three of the 19th century museum specimens (the fourth, which was collected on the eastern shore of Lake Te Anau, is thought to have been destroyed when the Dresden Museum in Germany was bombed during World War II; Ballance 2001) to evaluate trends in Takahe population size over the last c.150 years. Although the sample size is extremely small, molecular techniques may offer some insight into the effective population size and genetic diversity of the Takahe population at around the time of European settlement (Wandeler et al. 2007, Pruett & Winker 2008). We compare genetic diversity of the earliest samples with that of three additional museum specimens collected at the time the species was rediscovered in 1948, and with diversity of contemporary samples
from Fiordland birds.