Monday, 23 March 2009

WILD BLUESKIN Rare bird?

WILD BLUESKIN

Rare bird?

by Derek Onley

If you were in the Tarras area in the Upper Clutha Valley over the
last few weeks you may have witnessed some erratic driving and
strangely intense interest in barren paddocks. Cars that were creeping
along the road would suddenly accelerate then screech to a halt,
pulling off the road if you were lucky. Doors would fly open and in a
tangle of tripods and optical equipment more at home in a fashion
show, half a dozen bearded men or heavily anoraked women would stare
intently into the distance. 'Twitchers,' as they are called,
birdwatchers who pursue the rarest birds, observing the first ever
straw-necked ibis in New Zealand.

If you were in Karitane over the last few weeks you may have seen lots
of small pale seagulls on the sandbar down by the wharf. Every now and
then someone would launch a boat, collect a few cockles, wander out
there with their dog and the flock would fly up, swirl around for a
minute or two then land back on the sand, shoulder to shoulder, all
facing into the wind. Not a birdwatcher of any persuasion in sight,
yet 5000, or 1 in 20 of the world's total population of black-billed
gulls, was preening, bathing, squabbling or resting on that one
sandbar at Karitane.

Straw-necked ibises are big, heron like birds with long down-curved
beaks, black and white plumage and, as their name suggests, scruffy,
yellowish necks. They are common and obvious enough in Australia to
have attracted other less academic names like dryweather or letter
bird and farmer's friend due to their partiality to locusts and black
crickets.

Some half a million are estimated to live in Australia, Indonesia and
New Guinea and the Tarras twitchers were ticking off one poor
unfortunate bird that had managed to survive the Tasman Sea crossing
and find the habitat closest to the arid stocklands of home in the
paddocks of Central.

Black-billed gulls are not easy to tell from red-billed gulls, the
ones that hang around your beach picnic or barbecue and their names
are far from helpful. Some red-billed gulls have black bills and some
black-billed gulls have reddish bills. So forget the bills and legs
and look at the overall shape of the bird and its bill and the
paleness of its back. Black-billed gulls are slimmer and slightly
shorter-legged than red-billed gulls, with slightly longer, more
slender beaks and their backs are paler, appearing almost white in
open, sunlit estuaries.

Red-billed gulls are our common coastal gull and they also occur in
Australia and South Africa where they are equally keen on picnic
sandwiches and barbecue sausages.

Black-billed gulls only occur in New Zealand and are much keener on
healthy, wild food although some in Southland parks are picking up the
fast food habit. Nowadays most black-billed gulls nest inland in
Southland, Otago and Canterbury. Fifty years ago there was a large
nesting colony on the mudflats near Evansdale but these have long gone
and they are not doing very well in their inland nesting sites either.

Prey to cats and ferrets and flash flooding, their numbers have
declined in Southland by up to 80% in the last 30 years. Rachael
McClellan likened the colony she was studying in Southland to "a
fast-food joint for introduced predators such as cats and ferrets".
"In a little over two months one cat and possibly one individual
ferret had single-handedly killed hundreds of young chicks."

Every year after nesting they move to the coast, and every autumn some
thousands congregate at Karitane and Blueskin Bay, feeding on pink
krill beyond the breakers and returning at low tide to preen and roost
on estuarine sandbanks.

5,000 Black-billed gulls at Karitane or 1 straw-necked ibis in
Central. Which is the rare bird?

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From blueskin.co.nz and 'Blueskin News' published by Blueskin Media:
voluntary/non-profit community publishers in Blueskin Bay (Seacliff,
Warrington, Evansdale, Waitati, Doctors Point), Dunedin, New Zealand.
All material sent to or published by us is "copyleft" in the public
domain and may be freely shared, archived, re-edited and republished.
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