How do I spot them?
Feral pigeons form large flocks that roost on buildings, on ledges, sills and sloping roofs and under bridges. They prefer to eat grain and seeds, sometimes damaging flowers and leaves in gardens, but have adapted to become efficient scavengers - on rubbish tips, in the streets and at railway stations, and even on the mud of tidal rivers and the seashore. They will take food from bird tables and eat household scraps. They tend to feed where drinking water is readily available, and often feed at night in areas with artificial lighting.
How do they live?
Feral pigeons nest on ledges, roofs and in holes on buildings, bridges, piers, columns, and even cranes. If they can find an entrance they will nest in lofts. Feral pigeons may raise between three and six broods a year, and young birds may begin breeding when six months old. It is easy to see why their numbers increase so rapidly.
How do they affect me?
Pigeon droppings are acidic and cause damage to buildings and machinery, and also to lawns and shrubberies. Nest material, droppings and feathers can clog drains and air vents.
Pigeons carry many diseases, some of which can be transmitted to humans if droppings contaminate food stores, bakeries or canteens. They also carry a mite which causes skin disease, and feather dust can cause allergic alveolitis or 'pigeon fancier's lung'. Feral pigeon flocks can harbour Newcastle disease which can be passed to domestic poultry if their feed is contaminated by droppings.
Large numbers can drive small birds away from feeding areas, and may reduce their populations.
How do I control them?
The best way to control pigeons is to reduce the food supply by persuading people to stop feeding them so that the large flocks disperse, and to put rubbish in secure bins so they can't scavenge. Reducing access to nest sites will also help to limit the population.
To feed small birds in your garden without encouraging pigeons, put all food in feeders rather than loose on the bird table, or put food for ground feeding birds under a cage with a three-inch mesh size that does not allow pigeons and other large birds to enter but will let in blackbirds and thrushes.