The stake-out begins. On the roof of an office building in Bristol, Peter Rock sets up his telescope between sludgy rain pools filled with dark-green pigeon poo, and trains it on a bin on the pavement below. Standing on top of the bin, its beak hanging down into its contents, is a large, cocksure seagull taking a gluttonous interest in a packet of Hula Hoops.
Rock, a gull consultant, knows the bird's ring number without even looking. For the last two years, it has been claiming the bin as its turf. At this time of year, it shouldn't even be in this country, let alone intimidating litter-conscious pedestrians in Bristol. Ordinarily, it would be kicking up its feet on a sunny coastline in Spain, Portugal or Morocco; were it not for the lure of a better life in urban Britain.
The bin king is not alone. Up to 25 per cent of city-dwelling lesser black-backed gulls are now shunning migration for a winter in Britain, firing residents and buildings with their trademark black and white droppings. The numbers of urban gulls - the majority of which are lesser black-backed and herring - are on a dramatic rise. Rock estimates that at the end of last year's breeding season, there were around 500,000, a 10-fold increase in the last nine years. In another four, he predicts, the figure will have increased by 50 per cent.
Anyone who thinks that this isn't a problem should inspect Rock's scalp. "I used to get hit quite a lot, about six or seven times in the breeding season. I mean serious hits. Blood. It's always from behind with their claws. Don't think it doesn't hurt. They weigh a kilo and are flying at 40mph. Do bear in mind that the first birds you see being seriously aggressive in Alfred Hitchcock's The Birds are gulls," says Rock, 52, Europe's leading expert on urban gulls, who has been studying them since 1980.
The first warning that you may be in for a Tippi Hedren experience is aural. If you fail to clear off after the ominous "gagaga" call, you will be subjected to a low pass. Their next intimidation tactic will be to drop the contents of their bowels with the accuracy of a stealth-bomber. They will probably also vomit. "If you don't take the hint then, the last phase is the full-on attack," says Rock, who has witnessed three people being felled to the pavement in Bristol, which has one of the highest urban sea colonies in England.
If you are just knocked to the ground, you can count yourself lucky. In July last year, the worse month for assaults, since adult birds are protecting their offspring, Marie Munro ended up in hospital after weeks of intimidation by the same bird. Fed up with being stalked whenever she left her home in Weymouth, Dorset, she set off a personal alarm. The gull then started periodically dive-bombing her. After trailing her husband, and then attacking the couple in their back garden, the climax of its campaign of terror was a dive into Mrs Munro's face. She staggered back and fell, splitting a bone the length of her foot and tearing her tendons.
In July the previous year, Wilfred Roby, 80, a retired ambulance driver, died after an attack. He was clearing birds' mess from the roof of his garage in Benllech, on Anglesey, when a group of herring gulls began swooping on him. While trying to fight them off with his hands, he lost his balance and fell from the wall on which he was standing. By the time neighbours had reached him, he was dead. He is believed to have died from a heart attack. That summer, a worker at Western General Hospital, Edinburgh, needed emergency treatment after a dive-bombing seagull, nesting in the roof, floored him.
Seagulls have also caused a number of deaths in the sky. According to worldwide figures supplied by America's Federal Aviation Administration Wildlife Strike Database, 11 people were killed between 1912 and 1999 in plane accidents involving gulls. Three of the deaths took place in Britain. Most of the accidents occurred when the birds hit the windshield or got stuck in the engine. In the same period, 55 aircrafts were destroyed, injuring 28 people.
In Britain, the seagull population increased dramatically following the 1956 Clean Air Act, which prevented rubbish being burnt on tips and thus providing gulls with an unlimited food source. They outgrew their natural colonies and began nesting in towns and cities. With no predators, plenty of food, street lighting that enabled them to feed at night, and an ambient temperature two to three degrees higher than the surrounding countryside (which gave them a head start in breeding), they flourished. Bristol's first breeding pair arrived in 1972. There are now around 1,800 pairs.
Seagulls are now multiplying more successfully in towns than they do in the wild. Those studied by Rock in the Severn estuary region are raising two or three chicks per pair a year. However, on Skomer Island, a reserve off Pembrokeshire with a large gull colony of about 17,000 pairs, their breeding success rate in 2000 was 0.1 chicks per pair a year - which equates to one chick every 10 years. "The whole thing is about food," explains Rock. "They die at the chick stage because there isn't enough. Fishing practises have changed. Little inshore boats used to gut and discharge as they went, and the birds had regular, predictable food. Now there are large boats that discharge at any time of day or night. And the landfill in Haverfordwest closed in 1985."
Urban gulls are also starting to breed at a younger age than those in the wild, which means they produce even more offspring; they have breeding careers of around 10 to 20 years. There are now colonies in most towns and cities in the UK. Some are even breeding in London. There are pairs in Covent Garden, some near the Bank of England and others in Russell Street, WC1. And they will be here for many years to come. A lesser black-backed gull can live up to 34 years, and a herring gull up to 28.
As their numbers increase, so do the number of complaints registered at local councils. One of the most common problems is the gulls' ear-piercing wake-up call, which starts at around 4am. Then there's the mess. Many residents in Bristol no longer bother to clean their windows until the end of the breeding season. And, if having to drive a car covered in gull droppings weren't undignified enough, the acidic composition of guano also corrodes car paintwork. They also pull at the insulating material on roofs.
Seagulls have become such pests in Scotland - Aberdeen has the biggest colony in Britain, with around 3,500 breeding pairs - that the matter has been raised in the Scottish Parliament. Last November, Aberdeen City Council's SNP group leader Kevin Stewart suggested that they be put on the Pill. "Scientists have come up with contraceptives for animals, and I cannot see why we shouldn't look into it for seagulls," he said. "There's not much problem getting seagulls to eat, so if contraceptive pills were placed carefully, I am sure the birds would eat them."
There are other strategies that can be employed to deter urban gulls. Most, however, are palliative, says Rock, who works as a consultant to a number of councils trying to tackle the problem. One is to sterilise the eggs by coating them in white mineral oil, though this doesn't prevent the birds from breeding the following year. In other instances, plastic eagle owls are placed in order to scare the gulls away. But the seagulls simply sit on them. Electronic scaring devices that produce noises similar to birds of prey, loud bangs, ribbons and objects that make a waving motion have also been tried. While some work well at airports, where gulls don't breed, they have little success in cities.
"You can put spikes along the tops of buildings or tension wires, and the birds basically scratch their arses on them," says Rock. Roofs can be covered in nets, but if not well maintained, the birds will simply nest on top of them. Otherwise, they will set up home on the next net-free roof and the problem is simply moved several feet away. Some years ago, New England officials tried poison. The wind changed and dying gulls fell out of the sky into people's back gardens.
While there are more gulls in cities, the overall numbers of some species are in decline. Both the herring and the lesser black-backed gull are on the Birds of Conservation Concern list, a document compiled by the Government and various environmental organisations. The former appears because its numbers have gone down by 25 per cent over the last 25 years; the latter because over half of them breed in 10 or fewer sites, and Britain has over 20 per cent of the European breeding population. "We don't particularly know why the numbers are going down," says Graham Appleton, spokesman for the British Trust for Ornithology.
It provides little cheer for those plagued by gulls in their communities. Last November, the country's first ever Urban Gull Conference was held in Gloucester. Over 70 delegates from around Britain listened to presentations on the legal aspects of gull control and the need for more research. Rock, one of the speakers, is looking for funding for a three-year study in conjunction with the British Trust for Ornithology and Bristol University, where he is a research associate, to uncover the feeding regimes of urban gulls and produce strategies for managing the issue."What we don't know is where the hell they are getting this food from. It may be that they are getting their high-quality food from landfills, it needs to be determined," he says. "Within 10 years, all British towns will have gull populations. Cities will be noisier, messier place to live, not to mention potentially dangerous."
With this in mind, Rock is keeping firmly to the side of buildings. "The gull is a highly intelligent animal. They recognise me in the street. I know because I get swooped on more often than anybody else. As soon as I get out of my car I can hear the "gagaga" call, and they don't do that with normal passers-by. If I get out, and I've got a telescope on my shoulder, I start getting the low pass. I know how to avoid getting the rest of the stuff - you walk close to the side of the buildings, you stay in tight and keep your eye on the bird. He's not going to attack you if you're looking at him. I know seagull language, I know what's coming," he says.
Despite the skull-bashing he has received, Rock has developed a certain respect for his subject. He trains his telescope on to a particular roof. "That's where the very aggressive boys are," he says, his camouflage jacket zipped up against the wind. "One bird hit me there two years ago. I knew how aggressive it was. I was doing everything I needed to do - I was up against a wall and there was a big overhang of buddleia. I wasn't paying any attention to him because there was no way he was going to get in there.
"In order to hit me, he would have had to be flying sideways like this [Rock puts one arm up almost by his ear and the other by the side of his leg], and fly right into a very tight space. I got a whack on the back of the head and I thought, 'Well done mate'."Reuse content