There are two medium-sized, blue/grey gulls likely to be seen on the New Zealand coastline. The most common and widespread is the red-billed gull, which is pretty much confined to the coast. You will see one or two on most beaches in the Park and if you look offshore you may see small flocks of them, particularly when they are feeding on concentrations of krill and small fish.
The red-billed gull has adapted to other food sources and will be seen on flooded paddocks eating worms or patrolling seaside streets at night looking for discarded takeaways.
The nearest breeding colony is on the Boulder Bank at Nelson; another large colony can be found on the Kaikoura Peninsula.
Distinguishing this species from the black-billed gull is not as easy as the names suggest. The adult red-billed gull has a bright red bill and legs and a striking white iris. The difficulty in identification is that juvenile red-billed gulls have black bills and legs! However, the bill of the red-billed gull is always chunky when compared with the black-billed gull whose bill is always slender and black. Whereas the red-billed gull is coastal, the black-billed gull retreats to breed on inland riverbeds in Canterbury and Southland. During winter both might be found on the coast of the Abel Tasman National Park.