From some they are pests - for others a natural part of city life.

Eastern Daily Press: Seagulls around Norwich Market. Picture : ANTONY KELLYSeagulls around Norwich Market. Picture : ANTONY KELLY (Image: archant 2017)

But with the number of urban gulls in Norwich tripling over the last five years, bird experts have warned 'there is no solution'.

Coastal gulls are in steady decline as the birds migrate inland in search of 'easy pickings', with urban hubs littered with ready made meals over pavements or in bins and skips.

According to Dr Iain Barr, senior lecturer in ecology at the University of East Anglia, 'they are the new pigeon.'

With a few successful breeding grounds in Norwich, including the rooftops of industrial estates around Boundary Road and Vulcan Road in the Hellesdon area, Dr Barr said they are 'seizing an opportunity' after being displaced from natural habitats like Orford Ness in Suffolk.

Eastern Daily Press: NBC Environment's working birds are used to control species like gulls and pigeons to reduce their negatice impact on communities. Pictured are head of falconry, Andy Hulme and TJ, a Peregrine Cross Lanner Falcon. Picture: Ian BurtNBC Environment's working birds are used to control species like gulls and pigeons to reduce their negatice impact on communities. Pictured are head of falconry, Andy Hulme and TJ, a Peregrine Cross Lanner Falcon. Picture: Ian Burt (Image: Archant 2017)

'Now we have got the city birds breeding like mad and they can live for more than 30 years,' he said. 'They get aggressive when they have chicks - generally in the late spring and early summer.'

While predators have pushed birds like the lesser black-backed gull and the herring gull away from nature reserves, pest control experts say the reason they have descended on cities is very much a man-made problem.

'Our behaviour as humans has led to an abundance of rubbish and readily available food sources for them. That leads these birds to go for easy pickings,' says Stuart Miller, regional surveyor for the Norwich and Norfolk branch of NBC.

'Coastal gulls are in decline because they are moving inland and looking for alternative food sources.

Eastern Daily Press: Seagulls around Norwich Market. Picture : ANTONY KELLYSeagulls around Norwich Market. Picture : ANTONY KELLY (Image: archant 2017)

'If anything we are to blame. We can't ignore it when they move in - once they are there they have no intention of going anywhere unless there is a deterrent to push them away.'

While all birds are protected under law, there are measures that can be taken to reduce their numbers and push them away from city centres.

NBC Environment use birds of prey to disrupt nests if they become a problem, and can relocate eggs during breeding season.

Mr Miller added certain species of gull, such as kittiwakes, need to be 'left alone' due to population numbers.

Eastern Daily Press: Rachel Crockart. Picture: Eleanor TownshendRachel Crockart. Picture: Eleanor Townshend (Image: Archant)

'Some species of gulls such as herring gulls can be controlled under a general licence,' he said. 'We are licenced to take the eggs out of nests during the breeding season if we can deem they are a sufficient public health risk, either through fear of attack or a business being disrupted.

'We use birds of prey to change nuisance bird's behaviour. That can be in areas such as Lowestoft where we have been working this year to push them away from the business improvement district where they have become a nuisance to shoppers.

'People want to be seen to be doing something but also allowing nature to flourish. That is why falconry is a good option because it discourages them from areas we do not want them to nest.'

Complaints are on the rise in Norwich according to the city council, which is seeing an average of four complaints a month over the last three months.

'We have recently received complaints about litter issues caused by seagulls in the city centre,' said a spokesman.

'Our environmental protection team are working with businesses to deter gulls by reducing the time bags of trade waste are left out for collection and to see if clear waste sacks can be replaced with opaque bags where possible.'

But Dr Barr says he warned the city council years ago the problem had to be dealt with before it became impossible.

'Where the problem lies is they are a conservation concern but their numbers are increasing in the cities,' he said. 'We advised the council quite a few years ago that if they were going to do something about it they needed to do it now because it would grow exponentially to the point where it would be too difficult to solve.

'At the time there was no impetus or demand to do anything about it - there was no real drive because it is quite expensive to remove them.

'Now there isn't a solution that will work without a vast amount of money. They are very intelligent birds, taking advantage of an opportunity that gives good breeding success.

'Most of the time they are foraging around in our waste. They have also learned to have a slightly aggressive way of stealing food, and they will dive-bomb when they feel their chicks are under threat.

'Usually the first dive-bomb is a warning so the best advice is just to leave the area.'

'They took a sausage out of my dog's mouth'

There were mixed reactions from the people of Norwich, with many unconcerned about the rise of seagulls in the city centre.

'They don't really bother me; although you have to be careful as they can take something out go your hand,' says retired Margaret Skipper, 79, of Norwich.

'They're a lot bolder than they used to be'

Self employed beautician Joanna Jimenez, 25, said: 'I like them.

'I see them around, hear them squawk, but I haven't noticed a rise. There are always lots of seagulls around Morrison's stealing food.'

Student Rachel Crockart, 19, of Silfield, said: 'I hear them, they are loud but they're not in my way. They're just enjoying their lives. They are wild so we can't control them. It is inhumane to think about getting rid of them. But they do belong at the coast.'

But 53-year-old David, a teacher from Norwich had a tough time.

'They took a sausage out of my dog's mouth,' he said.

Gulls 'colonising' cities

Dr Barr started monitoring gull numbers in Norwich from 2008, and said in the last decade the numbers have exploded.

Now, he says, it is getting to the point were 'it becomes difficult to count'.

'In 2001 there was no records of any,' he said. 'The first breeding we were aware of was in 2008. By 2011 there was just over 300 birds with 25 chicks at a minimum. In 2015 there were 420 birds with at least 48 chicks.

'This year we have seen over 900 birds with 80 chicks. It gets to the point where it becomes difficult to count.

'Orford Ness in Suffolk is their main breeding colony which used to have up to 27,000 pairs of birds, but they seem to have shifted. Currently it is around 4,000 which is a significant, drastic decline. They think the population has moved inland and when they colonise a city they grow exponentially. They can travel a long way to feed and there is plenty of food in the cities so they are very successful.'

Birds can be killed 'as last resort'

The RSPB admit government licences allow the killing of urban gulls as 'a last resort' where there is a significant risk to public health or safety.

'The birds nesting on roofs of houses are most likely to be herring gulls, whilst lesser black-backed gulls tend to concentrate on the larger expanses of industrial or commercial buildings with flat roofs,' says the charity. 'Although numbers of roof-nesting gulls, especially lesser black-backed gulls, are still increasing, the overall population of herring gulls is plummeting, making them a red list species. The lesser black-backed gull population has also declined in recent years.

'While we understand that roof-nesting gulls can cause problems, we question the appropriateness of lethal control on a declining, red-listed species and highlight the need to comply with European bird protection law.

'As long as there are suitable nest sites and available food, random nest destruction alone is unlikely to work, since the birds will simply re-nest either in the same place or somewhere nearby.'