Tourists may enjoy feeding pigeons, but they're contributing to a growing problem with disturbing health implications. Nick Warburton looks at humane methods to reduce pigeon overpopulation

Every year pigeons cause millions of pounds worth of damage - destroying insulation in buildings, defacing surfaces and blocking pipes and gutters with droppings, which can lead to secondary damage such as wet rot. In addition, these "rats with wings" can carry up to 60 diseases, which can pose a risk to public health.

HEALTH RISK
Although the incidence of infection from pigeons is fairly rare, the fact remains that they carry diseases which can prove fatal for humans. Ornithosis, a nasty flu-like disease borne by birds, has seen an increase in infection numbers in the UK since the mid-1970s. Inhalation of dust from bird fouling can also transmit psittacosis, a type of pneumonia, which can kill. In May this year, a woman from Holland became the first person to die from pigeon lung. She had been sweeping her stairs and had inadvertently inhaled some dust containing pigeon droppings. These cases however, are few and far between and the main gripe continues to be the damage they cause and the problem of overpopulation.

CONVENTIONAL APPROACHES
Most methods of combating pigeon numbers are time-consuming and costly, and generally provide only short-term solutions. Fitting nets and wire systems can be quite effective, but often fail to tackle soaring population levels. Another, increasingly popular, method is the use of birds of prey (raptors), which are specially trained by professional handlers not to kill pigeons, and are principally used to deter them from nesting in specific areas. This method however, is only effective in confined spaces such as railway stations and needs to be employed in conjunction with other techniques for open space areas such as town centres. Some councils, which have seen their towns invaded by pigeon colonies, have resorted to shooting, clubbing and drugging the birds, which, besides causing immense distress to the birds and being messy, is also thoroughly unpleasant for those involved in the slaughter. Yet even these methods have made little impact long term.

A HUMANE ALTERNATIVE
A novel approach to combat this problem is being pioneered by Barking and Dagenham London Borough Council (EHN, 21 July, page 2). EHOs were anxious to find a humane alternative to clubbing and drugging pigeons, and 18 months ago approached Guy Merchant, an expert on pigeon control at the charitable organisation PICAS (Pigeon Control Advisory Service). Merchant drew the council's attention to a project undertaken in Basel, Switzerland between 1988-1992, which halved the pigeon population.

When Basel's local authorities found that successive years of mass culling had had little effect - the population simply replaced itself - the authorities realised that the root of the problem lay with people overfeeding the birds. It appears that adult pigeons usually breed between four and six times a year but can breed more frequently depending on the food supply. Experts discovered that if the food supply was reduced, adult birds might only breed once or twice or possibly not all. It was clear that rather than starving to death, when food is scarce, pigeons adapt to conditions and control population levels themselves. The local government subsequently asked the city's university to come up with a strategy to keep pigeon numbers in check.

The result was a public campaign to convince people not to overfeed pigeons and the setting up of designated feeding zones, where local authorities could control food quantities. In addition, the authorities built several well-kept and controlled nesting lofts close to the feeding zones. The idea was to encourage pigeons to nest and roost in the lofts, so that the pigeon population could be kept in one area. The sites would then be visited and cleaned on a weekly basis and all eggs laid in the preceding week would be removed. Not only did the lofts and feeding zones halve the population over the four-year period, but the lofts were inexpensive to build, install and maintain, and could be placed on the roofs of buildings away from public view, and near existing roosting sites.

Barking and Dagenham are now pursuing a similar scheme using a dovecote, a larger variation of the nesting lofts. The council is the first in the UK to follow such a policy and has set a precedent which is about to be taken up by other local authorities. Malvern Hills District Council has recently been given the green light to go ahead with its own dovecote. Andy Ferguson, environment team manager at the council, is optimistic. "It is the only method which will have a lasting reduction, but its success all hinges on clamping down on feeding outside the designated zones."

If the public could be encouraged to take a more proactive approach by not overfeeding pigeons, it would also benefit the birds' welfare, as feeding them scraps (rather than corn or wheat) makes them unhealthy. Still, as long as tourists throw crumbs in city squares, pigeons are likely to reap the benefits, so the results of this humane approach to population control are likely to be watched with interest.

For more information on pigeon control, contact PICAS on 01353 667230 or visit the website at: www.picas.org