Gulls get a pretty bad rap. If they aren?t eating our garbage they are attacking the nests of other „nicer? birds. They can be bad-tempered, aren?t especially colourful and can be a nuisance to humans. However, the gull should be appreciated as nature?s ultimate garbage disposal unit. They clean up smelly waste caused by thoughtless humans and have an important evolutionary niche. They are also quite intelligent. They adapt readily to almost any situation and can take advantage of even the most unfamiliar new food source. If the nuclear holocaust ever happens, you can add gulls to the list of adaptable rats, cockroaches, and ants that have a pretty good chance of surviving. Silver Gulls Living and going to school near the Derwent River, I spent every day of my life not too far away from a Silver Gull. Our lunch scraps were enough of an incentive for them to arrive as regular as clockwork at our normal break times. They jostled for the most advantageous begging position and made an annoying racket. We had a low opinion of them and taunted them. They were so common they seemed to be in plague proportions. In fact, recent counts now show the humble Silver Gull and Pacific Gull are in decline, with more than half being counted only at human garbage tips. For some reason they are being out competed by the Kelp gull. If they get pushed off the dumps by the larger birds, they can readily adapt to a new food source. Tasmanian bird enthusiast, Alan Fletcher, recently saw one that had adapted to looking for road kill and was tucking into a freshly killed rabbit. Others have been seen locally learning how to be insectivores. The recent plagues of European Wasps are being exploited by several species of birds including gulls. They can now be seen putting their flying skills to the test trying to catch the wasps in mid-air, “Several gulls lined up, some few metres apart, on the river’s edge, facing towards the sun, probably to silhouette the prey. Individual wasps were flying from the shore across the water. The gulls would spot them and give chase as the wasps climbed ever higher. To catch them, the gulls had to use all their flying ability, but I never saw them miss. They would usually descend back to the rocks to eat them, but I couldn’t determine whether they removed the sting before swallowing. I’d estimate that they were catching maybe 20 or Page 34 30 an hour, so it’s probably not going to make too much of a dent in wasp numbers, but every little helps” The Silver Gull is common throughout Australia and is also found in New Zealand and New Caledonia at virtually any watered habitat and is rarely seen far from land. Birds flock in high numbers around fishing boats as these leave or return to the coast, but seldom venture far out to sea. Silver Gulls nest in large colonies on offshore islands. Often two broods will be raised in a year, and both adults share nest-building, incubation and feeding duties. Eggs are laid in a shallow nest scrape, lined with vegetation. There have been programs of culling Silver Gull eggs, mainly on the causeways where they represent a driving hazard. Without reducing the amounts of our refuse, this might have simply led to more Kelp Gulls. Pacific Gull Larus pacificus The Pacific Gull is a very large black-backed gull with a large yellow bill, tipped with scarlet. The upper wings and wingtips are wholly black with a narrow white inner trailing edge, the tail is white with a broad black band near the end. The legs are yellow to orange-yellow. The Pacific Gull can be confused with the Kelp Gull, but that gull has a much smaller bill, as well as being much smaller and less bulky. Juvenile Pacific Gulls are mottled dark brown with pale face and the bill is pink with a black tip. The juveniles often get called “Mollyhawks”, but they aren?t a separate species of bird. The immatures have dark brown wings, whitish mottled body and a black-tipped yellow bill. The Pacific Gull forages along the coasts between the high-water mark and shallow water on sandy beaches, feeding mainly on molluscs, fish, birds and other marine animals. However, they do scavenge on human refuse at rubbish tips, abattoirs, picnic areas and on fish scraps near wharves. In some areas the Pacific Gull has adapted to drop shells and other molluscs, especially limpets and mussels, from a height onto a rock in order to break them open. On some islands and headlands, this has resulted in the formation of ‘middens’ of shell fragments that could be mistaken for ancient beach deposits. The Pacific Gull is endemic to southern Australia and occurs mostly on south and west coasts, Tasmania and infrequently on the east coast. The Pacific Gull prefers sandy, or less often, rocky coasts and sandy beaches. In eastern Australia, the Pacific Gull prefers areas that are protected from ocean swells such as estuaries, bays and harbours. It usually avoids human habitation but is occasionally seen on farmland and rubbish tips near the coast but rarely inland. It can be found roosting or loafing in elevated situations such as rocky headlands or on structures such as wharves and jetties. Page 35 The Pacific Gull breeds in scattered single pairs or small colonies on high points on headlands or islands. Both sexes build the nest with the female doing most of the incubation while the male forages for food and stands guard near the nest. The birds breed from September to December and lay 2-3 eggs that take 28 days to hatch. The Pacific Gull is easily disturbed by human activities at breeding sites and roosting areas, and have occasionally become entangled in fishing lines. Kelp Gull “And the winner is…the Kelp Gull”. The local availability of human rubbish has likely heavily advantaged the Kelp Gull, something of an „artful dodger? in the bird world. The Kelp Gull is the second largest gull in Australia and likes to hang out in large groups. It can scare off the opposition as well as harass other birds out of their nesting sites. They have taken over 40% of the Northern end of Orielton Lagoon and chased out the migratory wading birds. They have also beaten the Silver Gull and Pacific Gull to the choicest rubbish. They have increased in numbers 8 times since 1980 while the other species of gull are in decline. They are large, white-headed gulls, with a straight yellow bill . Newly-fledged Kelp Gulls are brown with paler mottling on the hind neck and breast and have a black bill. Immature Kelp Gulls have mottled brown wings and back with a whitish body and an all- yellow bill. The Kelp Gull has become established in Australia since the 1940s, with the first breeding recorded on Moon Island near Lake Macquarie in New South Wales in 1958. Their numbers have increased rapidly since the 1960s and they are now common in many parts of the south-east and south-west coasts, and especially in Tasmania. They are widely scattered through the southern hemisphere. It feeds mainly on fish and crustaceans, but will scavenge when an opportunity arises. Like the Pacific Gull, the Kelp Gull habitually drops molluscs from midair onto rocks to smash them. Kelp gulls are opportunistic feeders, preying on and scavenging molluscs, fish, crustaceans, other seabirds, and even their own chicks and eggs. They have also been seen eating amphibians, reptiles, worms, and even small mammals. They are accomplished food stealers and adapt readily to any new opportunity for a feed. Kelp gulls at Península Valdés, Argentina, have recently developed the habit of feeding on pieces of skin and blubber that they gouge from the backs of southern right whales. The level of harassment in 1995 was almost five times higher than when first studied in 1984 and they now disturb up to 25% of whale feeding time and may compromise calf development and might even induce right whales to abandon Península Valdés for other calving grounds. Like most southern seabirds, Kelp gulls breed in the summer months; November to December in the subantarctic. Eggs generally hatch in 23 to 30 days. Fledging occurs in 45 to 60 days, although chicks are still fed by their parents until after they can fly. Most Kelp gulls ultimately return to colonies where they were born.