Ornithologist Lyndon Perriman and Otago University
researcher Dr Chris Lalas visit the red-billed gull colony
on Taiaroa Head yesterday. Photo by Gerard O'Brien.
It is official, Otago's red-billed gull population has
more than tripled since 1992.
An annoying scavenger to many, the gull is classed as a
nationally vulnerable species - on the same level as
For many years, Lyndon Perriam, a ranger for the Department
of Conservation at Taiaroa Head, has kept an eye on the gull
colony at the headland, watching its gradual increase.
Now, a study he and marine science researcher Dr Chris Lalas
have completed confirms his belief they are flourishing on
Published in New Zealand ornithological journal Notornis, the
study was based on surveys of nests from Moeraki to Nugget
They found the number of nests had more than tripled since
1992 from fewer than 1500 to 4600-4700 in 2011 - 2200 of
those on Taiaroa Head, making it the most popular nesting
place for the endemic gulls.
Of the 26 breeding locations along the Otago coast, 16 were
on the mainland and the other 10 were on coastal islets.
Mr Perriam said this year, for the first time on the
headland, the gulls had ''hopped the fence'' and nested
around the viewing area below the albatross colony. They
normally concentrated their nesting next to the walkway up to
the viewing area.
''It'll be the largest seabird colony you can get this close
to - it's rare in New Zealand.''
The birds did not appear to mind the regular human visitors,
leaving a margin between their nests and the walking tracks,
The population's increase had been attributed to the predator
control undertaken for the albatross colony, rat control
around the gulls prior to 1999 and the easy access to food
such as krill at sea.
''Size matters - a decent sized colony means they can protect
themselves a whole lot better.''
The headland now provided ''a glimpse'' of what the mainland
could have been like before introduced predators, he said.
A previous study attributed the decline in the other major
gull colony, at Kaikoura, to a decline in the availability of
prey linked to changes in oceanographic indicators.
Fluctuations in sea surface temperatures at Otago and
Kaikoura might explain the trends in gull populations, with
the population rising in Otago, but dropping in Kaikoura.
Dr Lalas and Mr Perriam recommended future conservation
management at Taiaroa Head and at other key mainland breeding
locations was necessary to ensure the viability of red-billed
gulls in Otago.
''Future monitoring will help establish whether the recorded
declines at the main colonies either reflect an actual
overall decline in the New Zealand population or these
declines are compensated by increases at Otago.
''Above all, we regard control of predators and people at
important mainland locations as key to the viability of
red-billed gulls at Otago.''