Established Immigrants, Uncommon Residents… Kelp Gulls

By Keith Hutton on May 10, 2012 in Other

Everybody recognises Silver Gulls – noisy, arrogant, pearl-grey and white little seagulls that are common and widespread. They are not restricted to the coast and may occur far inland up rivers, on lakes and swamps, and around garbage tips.

There are also two other less familiar gulls resident in Australia, very different from Silver Gulls but difficult to distinguish from one another. Both are large, black and white in colour when full-grown, buoyant and majestic in flight, more or less confined to Tasmania and the southern coast of the mainland between Perth and Newcastle, and usually seen alone in the beaches and bays of Sydney’s east. Pacific Gulls are endemic, while Kelp Gulls are widespread in New Zealand, South Africa, southern South America and the Antarctic region, and are now established immigrants that breed in Australia.

Adult Kelp Gulls are big, black-backed gulls with white tails and small distinctive white patches near their wing tips. They have yellow bills with a small red spot, restricted to the lower part. Adult Pacific Gulls can be readily distinguished from them by their white tails with broad black sub-terminal bands, and wings that are wholly black except for a narrow white trailing edge; the tips of their massive yellow bills appear to have been dipped in scarlet paint. Juvenile and immature birds of both species are brown and develop their immaculate adult plumage over a period of three to four years. Pacific Gulls of all ages always have massive bills and juveniles are generally much darker than Kelp Gulls.

Coastal bays, beaches, reefs and islands are the preferred habitats for Kelp Gulls in Australia. I’ve seen adults and immature birds resting on the rock platform at Clovelly, on the beach at Coogee, and soaring and wheeling over the ocean off the cliffs at Magic Point on Malabar Headland. I’ve never seen adult Pacific Gulls in the Eastern Beaches, but have spotted juveniles in winter when they have always been alone and not too hard to identify, appearing very dark brown, particularly on the head, with obvious massive dark bills.

Kelp Gulls are largely carnivorous, opportunistic predators and scavengers. Their diet varies between seasons and localities depending on availability, and includes crustaceans, molluscs and fish, alive or dead. In New Zealand they have been seen dropping shellfish on to rocks or sealed roads to crack them open, and they will accompany whales and Leopard Seals, scavenging on disturbed invertebrates, scraps and offal.

Kelp Gulls have increased their range and abundance in New Zealand and a similar pattern has occurred in Australia since one was first reported in January 1938, with first breeding reported in 1958, both in NSW. Earlier arrivals may have been overlooked as a museum specimen collected in Western Australia in 1924 was misidentified as a Pacific Gull and the mistake was not picked up until 1964. There was rapid expansion in range and numbers in the last half of the twentieth century and Kelp Gulls are now even more likely to be recorded, with no apparent change in distribution over the last thirty years. They appear to be successful and thriving in their chosen localities in Australia.