EHJ March 2004, pages 80-82
This month marks the start of the breeding season for urban gulls. Peter Rock, an acknowledged expert on seagulls, explains what action local authorities should be taking to combat a growing menace

Wherever you may be in Britain, at any time of year, take a look around you and you'll see at least one large gull and maybe several - either herring or lesser black-backed gulls. If you're in town, have a look on the roofs and you'll know if your town is one of the many which have been colonised by these two species. It's odds on that you have a colony. If you don't, it won't be long before you do.

My research has revealed that gull numbers may be growing far faster than was ever anticipated. The last national survey in 1994 put the number of urban gulls in the Severn estuary region at fewer than 2,000 pairs. During the 2003 breeding season, I assessed 14 of the 70-odd colonies in the region and was surprised to find that this figure had risen 10-fold in only nine years. By extrapolation, I calculate that the region's urban gull population must now be about 20,000 pairs, with wild gulls being outnumbered three-to-one.

The large gulls started moving into town in the 1950s and 1960s and numbers began to rise during the 1970s. It was a surfeit of food at landfills that led to ever greater breeding success and traditional colonies were quickly outgrown. They had to go somewhere and, in town, they discovered that buildings became comfortable alternatives to their traditional breeding islands.

But this is just the tip of the iceberg. Urban gulls are very successful breeders, raising between two to three chicks per pair each year, in stark contrast to some wild colonies, where breeding success has been as low as one chick per pair every 10 years. It is this success that has fuelled the explosion in gull numbers.

Until the 1994 survey is repeated, there will be no exact figures for Britain's gull population. In the meantime, my research in the Severn estuary region indicates how national gull figures have grown. I estimate that, in 2003, there were at least 130,000 pairs nesting on rooftops in Britain's towns and cities. When non-breeders and the offspring of the year are included, it means that something like between 700,000 and 1 million gulls were associated with urban areas last year.

If we see the same growth rate over the next nine years, then we're looking at over 800,000 breeding pairs or 4 million large gulls by the end of the breeding season of 2012. This is why it won't be long before your town is colonised, with existing colonies seeing massive rises. 

There is, however, one serious limiting factor - food. Urban gulls have no predators, little disturbance and there is no shortage of roofs to nest on. So availability of food is key if such large numbers are to be supported. I feel that growth rates will slow down in the next nine years, especially in view of the EU requirement to reduce and, eventually, dispense with open-face landfills. But it's not a certainty. When I started looking at urban gulls in Bristol in 1980, there were 100 pairs and seven county landfills. Nowadays, the Bristol population is probably at about 1,800 pairs and there is only one small landfill.

Let's start from the premise that it is humans who offered the gulls an open invitation and they have shown that they're perfectly at home in town. It's a problem of our own making.

Back in the late 1960s and early 1970s, numbers of roof-nesting gulls were tiny and localised. Since then, numbers have risen exponentially, making this a regional issue. From colour-ringing data, it is clear that Bristol-hatched gulls are breeding in almost all of the region's urban colonies. It is, therefore, safe to assume that all colonies are exporting gulls in the same way. Similarly, we know that urban gulls are not now returning to the wild. They cannot go back to the seaside - there is no room for them anymore.

There needs to be a radical shift in perception on this issue and it ought to start with local authorities. Most councils seem to have no idea how many pairs are breeding within their jurisdiction and some aren't even interested. This is because they feel, understandably, that urban gulls are not their responsibility. A recent public survey in Bath, however, showed that 70 per cent of those asked felt that the issue should be the council's responsibility. If this is representative of the country as a whole, perhaps the voters need to be listened to.

To begin with, we need to assess colony sizes accurately and to locate, precisely, where gulls are breeding. It is only then that sensible policies can be formed. Monitoring future growth rates would also be extremely helpful.

Complaints to environmental services are on the rise, are costly to the council and are not going to go away. So, like Gloucestershire, you could form an action group. This group would comprise a range of stakeholders with representatives from the local authority, businesses, waste disposal companies, environmental agencies and experts in the field, with coopted members where appropriate. The terms of reference for such a group could be to investigate the social, economic and environmental impacts of your colony.

The costs of damage to property are relatively easy to work out. Window and masonry cleaning, litter clearance, repair to damaged roofs and roof plants and so on. There is also the effect on tourism, such as lost trade as shoppers fear visiting town centres where gull activity is intense, and lost work days from sleep deprivation. These findings should be shared with a regional group. This requires cooperation and funding, but spending money now will save your authority cash in the longer term.

This approach appears to have been overshadowed by stories of noise, mess and aggression in the news media, which appears either to take a tongue-in-cheek approach or to use the issue to have a go at the local council. Gulls in town can make sensational headlines but rarely do articles examine the facts seriously.

Culls are frequently called for. But the use of lethal methods like shooting or using poisons in towns is out of the question. Aside from the police response to discharging firearms in a built-up area, dealing with a colony of around 2,000 pairs - 4,000 adult breeders and about 2,000 non-breeders - the scale of operations would have to be massive and persistent. Even with expert marksmen, there would be risks to property and the public. One stray shot could end in tragedy.

The chemicals necessary for poisoning or to narcotise gulls are all proscribed. Even if it were possible to get a special licence, there is always the risk of someone being harmed. On a practical level, councils can use pest control agencies. However, beware - there are some professional outfits and there are the cowboys.

In more than 20 years of studying urban gulls, I've seen all of the various deterrence methods. They are costly and, in most cases, are little more than a slight inconvenience to the gulls. Some are simply laughable.

It is possible to exclude gulls from breeding on roofs by laying down netting and, for some, this might be a sensible solution. But you are likely to be moving the problem onto the next available roof, making it difficult to justify the cost. In areas where there is a high proportion of individually, colour-ringed birds, it is also possible to identify any such relocation. Netting can also be unattractive.

In the pest control business, there are the professional outfits and there are those that are not.  Anybody can set themselves up as pest controllers, buy equipment and set to work without any kind of understanding of what they're dealing with. The industry should think of introducing some regulation to protect itself from the cowboys. For the professional outfits, however, there is a serious role in this issue.

So, we're back to food. But we know almost nothing about the ecology of urban gulls and less about their feeding regimes. We don't know the significance of landfills, food scraps in towns, plastic bags, green fields, livestock feed, factory waste or natural foods. Feeding opportunities for urban gulls are legion. Precisely identifying them and analysing the role of each is where scientific research comes in. From these results, we can develop strategies to manage the situation. It will then be for local councils to debate implementation and for the professional pest control agencies to carry out the work. Strategies will need to be monitored to ensure that they are effective.

If we are to be successful in solving the problems thrown at us by urban gulls, we are all going to have to expand our thinking and work together. There is a great deal of unharnessed expertise out there and together we can do this thing - the quicker, the better.

Peter Rock has been the coordinator for the colour-marking of large gulls for all the bird-ringing schemes in Europe (Euring) for the last 16 years and is Britain's leading authority on urban gulls. For several years, he has advised local councils on the urban gull issue. He can be contacted by