Why growing population of pigeons is a problem

Population boom

The global population estimation of feral common pigeons (Columba livia) is c.26,00,00,000 (as per BirdLife International and International Union for Conservation of Nature). In one of the citizen science programmes launched to monitor common bird species of India, common pigeon topped the list with house crow following at number two. The reasons attributed to this is abundance and easy availability of food and urbanisation.
People feed pigeons for various reasons: on religious beliefs that feeding them brings prosperity, or on humanitarian grounds that they ought to feed them, else they'd die. Such artificial feeding has led to overpopulation of pigeons.

Maintain your distance!

Dr Kedar Toraskar adds, "Exposure to pigeons worsens the symptoms of patients already having asthma or bronchitis in a similar manner. The most important preventive measure is prevent further exposure to pigeons by removal of the source and thoroughly cleaning and clearing the contaminated area. Patients suffering from the above-mentioned should consult their physician immediately to prevent further progression of the disease and limit the damage to the lungs. Not only pigeons but other birds like parrots, parakeets, lovebirds and chickens can lead to this disease.?"

Wild v/s urban

In the wild, these common pigeons (previously known as the blue rock pigeons) are seen around cliffs and rocky areas, their preferred option for nesting. But their urban cousins have no dearth of choices: parapets, AC compressor units and similar flat surfaces in city buildings. This has led these pigeons to nest throughout the year; unlike in the wild where nesting season coincides with the food availability in nature.
In nature, predatory birds ensure population of pigeons, stays in control, but urbanisation has practically wiped out the predators. Add to this, provision of ready food has made pigeons in the cities lose their natural scavenging ability which is essential for any bird. Let the birds, not humans, decide what they wish to feed on!

The legal-illegal game

Since feeding the pigeons is related to religious beliefs, most feeding centres are situated near places of worship or community spaces. But few people know that most of these feeding sites or kabutar khanas are illegal. In Mumbai, there are only a handful of legal kabutar khanas among approximately half a million illegal ones. Local grocers are banking on this situation and their business is going great as the demand for grains is always high. There have been debates during sessions of BMC about banning such feeding centres altogether, but the corporation has been mum on this proposal since many years.
Just last month, a proposal was put forward to BMC by a corporator to use Ovistop, a contraceptive made of corn seeds which is covered with Nicarbazin, a coccidiostat, that reduces reproduction rate. But, this was shot down on terms of technicalities. So far, no definite solution has been adopted by the authorities. What makes these illegal feeding sites worse, is that they attract rats and mice and may lead to nutritional deficiencies in pigeons.

Wheezing alert

The worst part of feeding sites is that most of these erupt right outside places of worship or community related areas; making hundreds of people vulnerable to health hazards. Dr Kedar Toraskar, Consultant, Critical Care & Pulmonologist, Wockhardt Hospitals, Mumbai Central shares, "Frequenting kabutar khanas may lead to a disease called extrinsic allergic alveolitis, also known as pigeon breeders disease or bird fancier's disease. This is characterised by persistent dry cough, breathlessness, fever, malaise."
He adds that daily exposure to pigeons can lead to progressive symptoms like irreversible lung fibrosis and even death. These symptoms are induced by exposure to excreta and proteinaceous material on dried, finely dispersed dust from pigeons feathers.

Need for pragmatic approach

Various governmental authorities should take immediate steps to close down the kabutar khana and other pigeon feeding stations. The population of pigeons will thus move out elsewhere in the quest for food.
Use of some anti-fertility drug or such similar means to control the population without harming the pigeons should be considered, but it needs assessment for their impact on other birds too; as consumption of it by other bird species can't be totally ruled out. Impact of such anti-fertility drugs needs to be looked into for possible toxic effects down the food chain too.

(Kedar Gore is a biologist and wildlife conservationist; Dr Naveen Pandey is a veterinarian with experience in rescue and treatment of wild animals)

A menace worldwide

Dried droppings of pigeons contains spores, which if inhaled may lead to respiratory illness. Their faecal matter is highly acidic and may destroy buildings and monuments
Female pigeons can give birth to 48 squabs per year
Average lifespan of a pigeon is around 20 to 25 years
On an average, a well fed-pigeon creates around to 11.5 kg of toxic droppings per year

Global measures

Since 2001, a ban has been imposed on feeding pigeons at London's Trafalgar Square owing to health hazards
Since 2008, Venice introduced penalty on people who who sell grains for birds at St Mark's Square
Since 2015, Spain's Catalan town has been feeding pigeons Ovistop, a contraceptive made of corn seeds covered with Nicarbazin to control their population