Otago University masters student Robert Schadewinkel tracks
robins in the Orokonui Ecosanctuary yesterday.
Information gleaned from the experimental relocation of
robins to Orokonui Ecosanctuary will hopefully help with the
translocation of endangered species in the future, University
of Otago associate professor Ian Jamieson says.
Prof Jamieson and his team have been monitoring Dunedin's
small population of robins for three years and this year
translocated about 35 of the birds to Orokonui Ecosanctuary.
Dunedin's population of robins, estimated to be about 200,
was small and geographically isolated, he said.
They were found in native forest in the Silver Stream
catchment and in exotic forest in the Silver Peaks.
A robin at home in the ecosanctuary. Photos by Peter
McIntosh
Monitoring had shown they were under threat from
predators such as rats, stoats and possibly possums, with
between 30% and 80% of nests failing.
By translocating some of the birds to Orokonui, it not only
met its goal of returning the ecosanctuary to how Otago had
been 100 years ago, but also provided a third population of
robins, safeguarding the robins if something happened to the
wild population in Dunedin, he said.
"We're trying to develop better techniques. If we can test
the idea out on robins, it'll be a good model for threatened
species."
Twenty-five young robins, 19 from exotic forest just 9km from
the ecosanctuary and six from a small population at Flagstaff
were relocated in April.
"Nobody had moved the birds such a short distance for
translocation but it went well."
Surveys a week later detected only four of the birds inside
the sanctuary and the following week one of the birds was
found back at the Silver Peaks.
Further monitoring throughout this year had shown eight of
the birds had gone back to the Silver Peaks to the exact spot
where they were caught.
Robins had a strong homing tendency and it was thought the
young birds might have already established their breeding
territory before they were caught, he said.
Twelve were unaccounted for.
"Six birds stayed in the ecosanctuary, which was a good
result.
"We only need a few birds to stay and breed and for their
offspring to stay and settle."
Two pairs had bred and the first time they bred two chicks
fledged.
The second time three chicks fledged and the other pair was
sitting on four eggs.
Since November, they had "drip fed" nine chicks five or six
weeks old which had not "imprinted" their own territory into
the ecosanctuary.
Small radio transmitters were put on the birds so their
movements could be tracked.
"It's exciting now we know the detail of their day-to-day
movements."
The research was still in progress but so far seven were
still in the ecosanctuary and one had moved to bush on the
other side of the fence, Prof Jamieson said.
"The real test now is how many attempt to breed in the
sanctuary."
Another test would be to see how the birds bred in a
predator-proof enclosure compared with those in the wild, he
said.
rebecca.fox@odt.co.nz
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