Bird watching on New Zealand - Black-billed Gull

The Black-billed Gull (Chroicocephalus bulleri), also known as Buller's gull, is a species of gull in the family Laridae. It is found only in New Zealand.

Distribution and habitat
The black-billed gull is endemic to New Zealand. Its natural habitats are rivers, freshwater lakes, freshwater marshes, sandy shores, pastureland, and urban areas. It is threatened by habitat loss. About 78% of the population breeds in the Southland Region on the southern end of South Island, New Zealand, especially beside the Mataura, the Oreti, the Aparima and Waiau Rivers.

On the North Island, breeding sites are typically sand-spits, shell banks, lake margins and river flats. It feeds on fish, terrestrial, freshwater and marine invertebrates and visits farmland and refuse tips.

Range map from www.oiseaux.net - Ornithological Portal Oiseaux.net

www.oiseaux.net is one of those MUST visit pages if you're in to bird watching. You can find just about everything there

Taxonomy
As is the case with many gulls, it has traditionally been placed in the genus Larus, but is now considered to belong within the genus Chroicocephalus. The holotype is in the collection of the Museum of New Zealand Te Papa Tongarewa.

Description
The black-billed gull is a lightly coloured gull with a small amount of black on its wingtips. It has a long, thin, black bill with a bright red interior, and reddish black feet and white eyes. The juvenile has a flesh coloured bill with a dark tip and dark brown eyes. As juvenile red-billed gulls display similarly dark bills and feet they may be confused with this species.

Listen to the Black-billed Gull

Sound from www.xeno-canto.org

Remarks from the Recordist

Natural short calls from a perched adult individual along the shore of the lake.

When giving this vocalization, the bird leaned its neck forward and opened bill, but did not adopt any strong posturing.

Status
The black-billed gull has shown a marked decline in numbers since about 1980. A census in 1996 showed 48,000 nests which would equate to about 96,000 mature individuals. The bird faces threats from various predators that eat eggs and chicks. These include brown rats, weasels, hedgehogs and feral cats. Nesting colonies are disturbed by people and river modification through dredging or abstraction of gravel and water also impact on them. For these reasons, the IUCN has rated the species as being “Endangered”

Important Bird Areas
Sites identified by BirdLife International as being important for black-billed gull conservation are:

Canterbury Region
• Ashburton River
• Opihi River
• Opuha Dam
• Orari River
• Rakaia River

Southland Region
• Aparima River
• Eyre Creek
• Mararoa River
• Mataura River
• Oreti River
• Whitestone River

Conservation status

Endangered (IUCN 3.1)

IUCN Red List of Threatened Species. Version 2015.4. International Union for Conservation of Nature. Retrieved 4 January 2016.

From Wikipedia, the free encyclopedia