Red-billed gull (Larus novaehollandiae)
It is estimated that 5000+ pairs breed on the Kaikoura Peninsula. Here, these birds have been extensively studied since the 1960’s with research on their social organization and particular habits. Birds with colour bands on their legs are frequently seen both on land and at sea around Kaikoura.
The gulls breed from early October to late December, laying one to five eggs. Both sexes incubate the eggs and provide food for the chicks before fledging around 37 days old but remain dependent on their parents for a further 3 weeks.
Birds vacate their breeding grounds in early autumn, although most birds remain within 400km of their breeding colony. Research on banded birds in Kaikoura has shown that some birds have been seen as far away as Auckland and Invercargill.
Life expectancy for female gulls is around 9 years and males about 6, but some live up to 25 years. The oldest bird recorded lived till at least 28 years old.
The diet during the breeding season is focused mainly on krill in inshore waters, but can also include other invertebrates, small fish and even terrestrial insects. In autumn and winter, the diet varies and includes carrion, fish, and shellfish and fisheries offal.