SYDNEY, July 21 (Xinhua) -- Seagulls have hit record numbers in Australia's Tasmania island state, baffling ornithologists and animal watchers who also highlighted the birds' changing food supply and nesting areas, latest conservation group figures showed.
All major gull species in the southern state's southeast area have increased significantly, with a nearly 200 percent rise in Pacific gulls from last year's numbers to surpass 1,000 birds, according to bird conservation group Birdlife Tasmania's annual winter gull count reported late this week.
Silver gulls recorded the second-highest population in more than three decades, at about 16,000 birds, the group's Eric Woehler told local media.
The exact cause of the record number of seabirds, some of which can live for 30 years, was not known, said Woehler.
"Every year the gulls surprise us ... The different species respond differently to the environment," the ABC radio channel in state capital Hobart quoted him as saying.
The seabirds were also shifting away from dwindling food sources scavenged from rubbish dumps to feed in other spots including fish farms in water channels, said Woehler.
Seagull nesting areas were similarly changing amid their rising numbers.
"What little roosting space there is around here has become highly competitive," the radio channel quoted waterfront worker Jack Cooper as saying.
Tasmania's winter gull count is touted as the country's longest-running survey of its kind, with the birds tracked since 1980.