BLACK BILLED GULL

New Zealand's BLACK-BILLED GULL ( Larus bulleri )

The world is home to 88 species of the family laridae, comprising of gulls (47), Terns (37) and noddies (4).
resident here in new zealand, we have 6 terns, 4 noddies, and 3 species of gull, Larus dominicanus, l. novaehollandiae and l. bulleri.

Black-billed Gulls are the most threatened of our gull species. They nest predominantly on gravel river beds or shingle coastline. Black-billed gulls have a somewhat asynchronous breeding season, streching for perhaps 3-4 months from choosing of a site to its abandonment. This increases the chances of predation at the colonies by stoats, rats, ferrets or humans, as well as increasing the chance of flooding at a colony.

Photographing Black-billed Gulls is easiest at colonies. If you are careful enough you can get to within 5 or 6 metres of a bird.

About half to three quarters of the world population of Black-billed gulls (they are endemic to New Zealand) nests on the river beds of the Southland region - the 4 major rivers being Waiau, Aparima, Oreti and Mataura. Southland ornithologists are keeping a close eye on these birds. Flights up these rivers in November determine the position of colonies and photographs taken from the plane allow the numbers of birds to be counted with incredible accuracy. From there, ground visits to colonies can be undertaken to band birds or make general observations.

Black-billed gull colonies can range from 50 birds right up to 40 000+. Large colonies occurred frequently in the past but recently there have been very few. Nests measure about 20-30cm in diametre, and are spaced throughout the colony at about 50cm intervals. colonies are noisy places, with all the gulls screeching in an attempt to ward off intruders from their territory.

Black-billed gulls are banded throughout the country. The Southland study has been running for two seasons now. We band juveniles at 2 colonies every season. Each colony has it's own individual colour combination. The gulls banded in Southland can be identified as to their colony and year banded - just by the colours. It seems all the other Black-billed gulls in New Zealand are simply banded with a regional colour. This means observations of Southland gulls in the field have a great importance.

Colour combinations used in Southland so far. From left to right : Benmore 1997, Mossburn 1997, Thornbury 1998 and Benmore 1998. The majority of recoveries have been gulls from the Mossburn Colony.

The total number of Black-billed Gulls banded in Southland during 1997 and 1998 now numbers over 400. Of these, only a few have been seen or recovered so far.
They were :

E196990 found dead on Otago Peninsula. The bird was found 52 days after being banded - and was found 200Km from it's natal colony.
E196983 found as a fresh roadkill between Oamaru and Dunedin. The bird was found 42 days after being banded - and 210Km from it's natal colony.
E196969 found dead on the Waiau River Bank. The bird was found exactly 6 months after it was banded - 75Km from where it was banded.
There has been a report of a dead banded Black-billed gull on an Invercargill footpath - Jan 1999. The bands were white, red and blue indicating it was from Mossburn. This would put the gull at 13 months from banding, and 80Km from the banding site.
E199122 found dead on the beach 2km south of Waitaki River Mouth - found 73 days after being banded, 250km from it's natal colony.
One bird from Benmore 1998/99 and one bird from Thornbury 1998/99 were seen at Papanui Inlet on 16 Feb. 1999, 180km and 210km from their colonies respectivly.

Victory Beach and Papanui Inlet, Otago Peninsula, where some of the Southland Gulls turned up.

Anyone interested in further information regarding this species should feel free to email me at danja@es.co.nz