Property and health: the problem of pigeons

Dealing with flying rats

28 November 2018

In his continuing series of articles on the link between properties and ill health, Mike Parrett looks at how pigeons can cause problems for homeowners

Feral pigeons (Columba livia domestica) have become increasingly difficult to control, especially in inner cities, towns and villages. Buildings and structures such as railway bridges provide a habitat for them to nest and roost in places such as ledges, roof slopes – especially under solar panels – parapets, chimney box gutters and balconies, while large rainwater hoppers make for ideal nesting boxes. Derelict buildings with broken windows and missing roof tiles provide easy access, especially to lofts.

Pigeons thrive in squalor and will nest in places that other feral birds would not consider. They will nest on their own excrement, mixed with any nearby material such as loft insulation, which can block drainage outlets to cause localised flooding. Regular fouling with faeces builds up over time and presents a health hazard, and surfaces can become slippery when wet. Socially monogamous, a pair can breed up to 6 times annually, at any time of the year. They are attracted to built-up areas by food sources – especially litter – and roosting and nesting sites. They cause problems include fouling pavements and buildings, odours, noise and disease transmission.

Under the Wildlife and Countryside Act 1981, it is illegal to kill a wild bird, including feral pigeons. However, if there is a nuisance – defined by the act as 'fouling pavements, buildings and monuments, contaminating food stores and in some cases transmitting diseases' – the public can engage a professional pest control organisation that has been granted a general licence to deal with the problem.

Health issues

Pigeons are not known to carry the deadly bird flu virus and rarely transmit diseases to humans. The main threats arise from their droppings becoming very dry in warm weather and particles becoming airborne. This can cause the following conditions.

  • Psittacosis: pigeons can carry the bacterium without any signs of illness. Transmission to humans may occur through feather dust or direct contact. It can cause severe respiratory problems, flu-like symptoms and even pneumonia
  • Salmonella: pigeons will generally appear ill, lack energy and remain close to food. The disease is usually transmitted through infected droppings, especially around water and food containers. It can cause diarrhoea, fever and vomiting.
  • Paratyphoid fever: also caused by salmonella, symptoms can begin between 6 and 30 days from exposure and result in a high fever and skin rash similar to a mild form of typhoid.
  • Histoplasmosis: may cause fever, coughing and fatigue and more serious respiratory problems in those with weakened immunity. It may be fatal.
  • Candidiasis: a yeast or fungal infection that can affect different parts of the body.
  • Cryptococcosis: caused by yeast found in the intestinal tract of pigeons, and transmitted through dried droppings. Symptoms include fatigue, fever, headaches, nausea and skin rashes. More serious complications can occur in those with weakened immune systems. The disease can attack the nervous system and lead to seizures.

Treatment

Not feeding pigeons is the most effective way to control their numbers, especially in large public spaces. Some people still regularly leave food for pigeons, which encourages flocks to target these areas. These can range from 20 to 500 in number, and large flocks increase the risk of disease transmission. Educating the public and homeowners on the risks of feeding pigeons is important to help reduce the associated problems.

Regularly removing pigeon droppings and installing preventative measures to deter nesting and roosting prevent the spread of diseases, including:

  • introducing adult falcons to the area to scare away pigeons
  • installing spikes or coils on ledges and other flat surfaces
  • installing nylon netting around balconies or under bridges
  • applying a non-drying gel to surfaces
  • coating eggs with oil to prevent hatching – this requires a licence from the Department for Environment, Food & Rural Affairs
  • using ultrasonic and sonic deterrents that broadcast the sound of birds of prey
  • making architectural changes to buildings to reduce the number of flat surfaces available, because pigeons do not like steep sloping surfaces such as mansard roofs.

The Royal Society for the Protection of Birds (RSPB) says that preventing access to food is key to deterring pigeons. It suggests that when feeding smaller garden birds, all food should be caged so pigeons cannot reach it. Pigeon-proof feeders are commercially available. The RSPB also says that homeowners should avoid offering certain food mixes that contain whole grains such as corn, wheat and barley, which are more likely to be eaten by pigeons.

In London, the Local Government Association, in consultation with the RSPB, has published Prevention of Nuisance from Birds: Code of Practice for exercising the powers under section 9 of the London Local Authorities Act 2004. This sets out a strategy for dealing with all types of bird nuisance.

The UK’s Health and Safety Executive has also published Construction micro-organisms: Psittacosis and other diseases from work involving bird droppings, because construction workers may be exposed to bird droppings on site. Suggested actions include preventing any faecal dust becoming airborne by wetting down work areas and using protective respiratory equipment.

Network Rail has installed extensive netting to the underside of many of its bridges to deprive pigeons of common roosting and nesting sites. It has experimented with repellent paint systems that aim to cause a harmless allergic reaction in pigeons, creating a conditioned response.

Case study

I was involved in a large-scale pigeon problem at some blocks of flats in south London. Constructed in the 1920s, these 4-storey buildings had mansard roofs, dormer windows and open balconies leading off the kitchens of each flat. Pigeons were roosting on the upper roof slopes, the flat tops of the dormer windows and balcony walls and nesting on the flat roofs over the stairwells and on balconies.

Some residents used the balconies for storing prams, bicycles and furniture, which provided the perfect habitat for pigeons to roost and nest undisturbed. A colleague attempted to mount 2-foot plastic owls in various places as a deterrent, but the pigeons were intelligent enough to understand that these were not a threat.

An RSPB feral pigeon expert confirmed that these owls were useless and that birds of prey were the most effective deterrent, together with changing flat surfaces to steep slopes or pyramidal shapes. The advice included the standard deterrents mentioned earlier, such as a non-drying repellent gel. A leaflet was delivered to every resident asking them to stop leaving food for any wildlife and ensure balconies remained clear and clean; netting was also installed around these.

Such measures largely brought the problem under control, and though they did not completely eradicate the pigeons they prevented them from being a nuisance to residents.

Conclusion

The challenges and costs for industry and local authorities can be considerable when attempting the wholesale control of pigeon populations. Shooting, poisoning, contraception and electric shock measures are all illegal under the following UK legislation:

Eradicating a pigeon infestation is difficult and may require a combination of measures. The birds need to know they are unwelcome, so not feeding them is an important first step.

Regular building maintenance is important to eliminate any structural weaknesses that allow them access, such as missing eaves soffit boards. Neighbours of a homeowner carrying out such measures will have to do the same, otherwise the pigeons will just move to the next easy target.

Making architectural changes to buildings requires increased consideration from designers, large landlords and building owners. Retrofitted deterrents need to be regularly maintained – we have seen many that have fallen into disrepair or been vandalised – otherwise this stubborn and persistent nuisance will return.

Mike Parrett is a building pathologist, chartered building surveyor and founder of Michael Parrett Associates. He is an Eminent Fellow of RICS and the lead author on the Damp section of isurv

Further information

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