Mon, Jul 18, 2016 - Page 8 News List

The secret life of British seagulls

Study tracked four herring gulls nesting in Cornwall with GPS tags through a summer

By Steven Morris  /  Cornwall, The Guardian

A gull sits on a rail above a “Beware The Gulls” sign in St Ives, southwest England, where the gulls tracked in a recent study nested.

Photo: Katherine Hadden/AFp

The summer holidays are nigh and with them, no doubt, will come stories of seagulls on the rampage, stealing ice cream and chips and launching attacks on people and pets.

But a ground-breaking study that tracked the movement of herring gulls nesting in the Cornish resort of St Ives suggested they spent little time scavenging for goodies or scraps on the streets.

It turned out the four of the birds studied each had their individual ways of operating. Two of them habitually headed far out to sea, one flying as far as Wexford County in Ireland, while the others stayed close to St Ives but spend much more time foraging for food on farmland than in the resort.

In all, the four birds completed almost 2,300 trips over 100 days during the breeding season of 2014 and traveled a total of more than 32,000km.

Peter Rock, the lead author of the study, said much was known about rural gulls but relatively little about urban-based one like these four.

“They have been under-studied so our knowledge of urban gulls is nowhere near as good as it should be. In view of the bad press surrounding urban gulls, it’s a situation that must change and this small study points the way,” he said.

Viola Ross-Smith, of the British Trust for Ornithology and a huge fan of gulls, said the findings showed that there could not be just one simple solution to the perceived problem of the birds.

“This study demonstrates that gulls behave as individuals and there can be no one size fits all approach when it comes to managing their populations,” she said. “It is vital that any decisions about gull conservation and management are based on the best scientific evidence available if they are to succeed.”

The study involved researchers attaching solar-powered GPS tags to the herring gulls, two male, two female, nesting on the rooftops of St Ives and tracing their movements through a summer.

It turned out the gulls, from four different nests, acted in very different ways. One of the birds, a male known as G4036, roamed widely, ending up as far afield as the Irish mainland and did not mind spending nights bobbing around out at sea. He was found to have visited Lundy island in the Bristol Channel and the Saltee islands off Wexford County.

A female called G4038 ranged primarily over land or within a mile or so of the shore but also occasionally took long trips out to sea.

By contrast, another female called G4037, which bred on the same roof as the prolific seafarer, and a male, G4039, rarely went more than a few hundred meters over water and then usually only to cross Carbis Bay on the way to the Hayle estuary. Their activity was concentrated during the day while the other two were out and about at night.

The data gathered revealed only occasional GPS fixes for the four in the streets of St Ives close to their nests, at which time they may have been picking up scraps of human food.

But they did spend much more time at a farm inland where there was a large heap of animal feed and in fields where they were probably hunting for invertebrates, small mammals, nestlings and amphibians disturbed by farm machinery during hay cutting and other farming activities.

The study is the first in which rooftop nesting herring gulls in the UK have been tagged and tracked.

Though gulls appear to be thriving in some areas, many species are in decline nationally, including the herring gull, which is on the UK red list for birds.

Comments will be moderated. Keep comments relevant to the article. Remarks containing abusive and obscene language, personal attacks of any kind or promotion will be removed and the user banned. Final decision will be at the discretion of the Taipei Times.

TOP top