Rock pigeons, also known as common pigeons or city pigeons, are a familiar sight in urban areas around the world. These sturdy birds are well adapted to living alongside humans in cities, often nesting on building ledges and scavenging for food left behind by people. Though rock pigeons are sometimes viewed as pests, they also provide benefits to city ecosystems. However, large populations of rock pigeons can cause some problems too.
What are rock pigeons?
Rock pigeons (Columba livia) are a domesticated variety of pigeon that originally lived on cliffs and crevices in rocky coastal regions. Over time, these nimble birds adapted to nesting on man-made structures and scavenging in urban environments.[1]
Key facts about rock pigeons:
– Scientific name: Columba livia
– Native to: Coastal regions of Europe, North Africa, and South Asia
– Habitat: Nests on building ledges, eaves, bridges etc. in cities; forages for food scraps on streets and sidewalks
– Diet: Omnivorous; eats seeds, fruit, vegetables, breadcrumbs, insects etc.
– Weight: 250-350 g (9-12 oz)
– Wingspan: 62-72 cm (24-28 in)
– Lifespan: 2-5 years in wild; 10+ years in captivity
Rock pigeons were domesticated thousands of years ago and have depended on proximity to humans for survival for centuries. Feral city pigeons are the free-living descendants of domestic pigeons.
Why are rock pigeons considered a problem in cities?
Though pigeons are a normal part of the urban landscape, large concentrations of these birds can cause some problems, including:
Mess from droppings
Pigeons produce a lot of feces, which can collect on building ledges, sidewalks, public squares, and other areas. Pigeon droppings are unsightly and can cause sanitation issues. The acidic nature of their droppings can also damage stone and metal structures over time.[2]
Possible health risks
Pigeon droppings may harbor disease-causing organisms like E. coli, Salmonella, respiratory fungal spores, and more. In rare cases, people can get sick if they have contact with accumulating bird droppings. However, the risk of disease transmission to humans is very low in most settings.[3]
Damage to property
Nesting birds and their droppings can damage or corrode building exteriors. Pigeons sometimes get stuck in ventilation systems or clog drainage pipes with nesting materials. Their feathers and debris can also get caught in machinery like escalators or turbine vents.[4]
Agricultural damage
Flocks of foraging pigeons can damage crops in rural areas. The birds peck and feed on cereals like wheat and rice, brassicas, legumes, and other crops, reducing yields for farmers. They eat both planted seeds and mature cereal grains.[5]
Nuisance behaviors
Certain pigeon behaviors may bother some people:
Cooing sounds
Pigeons frequently coo and make murmuring sounds, both for communication and courtship. The resonant coos can be loud and persistent, especially in the early morning and breeding season. For some people, the repetitive cooing is bothersome.[6]
Aggressive food-seeking
Flocks of pigeons often boldly beg for food from people eating outdoors. They will swoop in close and may attempt to steal snacks or scraps if people feed them. Some find their behavior aggressive and irritating.[7]
Roosting and nesting
Pigeons tend to roost and nest in large groups. Dense clusters of roosting birds can be noisy and leave behind mounds of droppings. Their nest materials and droppings may fall from ledges onto sidewalks or building entrances below.[8]
Do pigeons pose a serious disease risk to humans?
While pigeons can harbor and spread diseases, the actual risk they pose to human health is quite low. Here are some key facts:
– Pigeons do not typically transmit diseases directly to humans. Their parasites and infections tend to be species-specific.[9]
– Outdoor spaces like parks, plazas, and sidewalks where pigeons congregate pose little hazard, as casual contact has an extremely low risk of transmission.[10]
– Accumulated droppings in enclosed spaces like building ventilation systems can potentially cause symptoms in people with allergies or compromised immune systems. But serious illness is rare.[11]
– Cases of diseases passing from pigeons to humans, such as psittacosis, are very uncommon and have become less common with modern medicine.[12]
– Regular cleaning and disinfection of areas frequented by pigeons helps minimize any disease risks.[13]
So while pigeons can theoretically spread diseases, the chances of them infecting humans under normal city conditions is extremely slim. The main health hazard posed by large flocks is from droppings accumulating in enclosed spaces.
What diseases can pigeons potentially spread?
Pigeons can carry and spread a variety of infectious agents. However, most of these present a low risk to humans. Potential pigeon-related diseases include:
Histoplasmosis
Histoplasmosis is caused by a fungus that grows in accumulated bird and bat droppings. In rare cases, people can get sick if they breathe in the fungal spores. It is treatable.[14]
Cryptococcosis
Another fungal disease that can inhabit droppings. The greatest risk is for immunocompromised people handling infected droppings.[15]
Psittacosis
Also known as parrot fever, psittacosis is a bacterial disease that can spread to humans. But modern antibiotics make this rare today.[16]
Salmonella
Pigeons can contract salmonella from uncooked food waste and their droppings may contain salmonella bacteria. But transmission from pigeons to humans is unlikely.[17]
E. coli
Pigeon droppings may contain E. coli bacteria. But like salmonella, infection from a pigeon is very unlikely under normal exposure.[18]
Bird mites
Pigeon nests may harbor bird mites that could bite people handling the nests. But they do not reproduce on humans.[19]
So while pigeons can become infected with or spread various organisms, most of these present a low hazard to human health, especially with reasonable precautions.
What damage can droppings cause to buildings and infrastructure?
Accumulation of pigeon droppings can cause following types of damage to buildings and infrastructure:
Corrosion
The high acid content of pigeon droppings can slowly corrode metal fixtures like railings, beams, sculptures, and pipes. The droppings can also etch into stonework.[20]
Degradation of surfaces
Pigeon droppings may gradually degrade exterior paints, wood surfaces, mortar between bricks, stone tiles, and more. The speed of damage depends on volume of droppings.[21]
Blockages
Nests, eggshells, feathers, and corpses can block gutters and drain pipes. Droppings can also get sucked into air vents and accumulate to restrict airflow.[22]
Fire hazards
Nests near electrical wiring can be fire hazards. Large amounts of dry droppings can potentially fuel blazes in enclosed spaces.[23]
Structural concerns
Large piles of droppings can be unsightly and cause unpleasant odors. In addition, the extra weight from accumulated droppings can become a structural concern over time.[24]
Regular cleaning and exclusion of pigeons from problematic areas are the best ways to prevent droppings damage to buildings. Seeking professional help is recommended in severe cases.
Examples of problems caused by pigeon droppings
Corrosion of metalwork
– The acidic droppings etched pockmarks into the copper statue of Gandhi in New York City over decades.[25]
– Pigeon droppings contributed to rust and decay of the steel framework of the Eiffel Tower in Paris.[26]
Degradation of historic buildings
– Centuries of pigeon droppings eroded the brickwork of St Paul’s Cathedral in London.[27]
– Droppings damaged the marble and limestone features of many iconic buildings around Trafalgar Square.[28]
Infrastructure issues
– Nesting materials blocked air intakes at Vancouver’s Rogers Arena, causing indoor air issues.[29]
– Droppings were partially blamed for a 2015 power outage in Oklahoma City.[30]
So while pigeon droppings cause relatively minor degradation over time, their impacts can become quite costly for cities and historic sites when left unchecked.
Are there any health benefits to having pigeons in cities?
There are a few potential health benefits associated with urban pigeon populations:
Disease monitoring
Public health agencies can monitor pigeons for potential outbreaks of diseases like West Nile virus. Since pigeons don’t migrate over long distances, local testing provides localized data.[31]
Allergy protection
Exposure to pigeon droppings early in life may reduce kids’ risk of developing certain allergies. The droppings contain molecules similar to common allergens.[32]
Antibiotic source
Compounds in pigeon droppings show promise as a source of new antibiotic medications for resistant infections.[33]
However, experts emphasize these possible benefits don’t outweigh the need to control overly large flocks in cities. Monitoring, research, and protection can still be achieved with smaller, healthier urban pigeon populations.
What methods are used to deter or relocate urban pigeons?
Various deterrents and relocation methods are used to manage pigeon overpopulation in cities:
Spike strips
Rows of spikes placed on ledges to prevent pigeons from roosting or nesting. Often made of thin, flexible metal.[34]
Netting
Mesh netting can be installed over alcoves, eaves, windows, or other areas to block access and exclude birds.[35]
Repellent gels
Non-toxic gels containing mint oil or capsaicin can discourage roosting. Applied in strips near pigeon favorite spots.[36]
Falconry
Trained hawks or falcons hired to scare and chase away nuisance pigeon flocks from a property.[37]
Live traps
Pigeons are humanely caught in cages, then relocated to alternative sites such as pigeon lofts.[38]
Birth control
Feeding flocks contraceptive food laced with OvoControl P reduces egg hatching and population growth.[39]
Culls
As a last resort, some cities trap and euthanize pigeons to quickly reduce large problematic flocks.[40]
An integrated pest management approach using multiple methods is usually needed for effective, lasting pigeon control.
What are humane methods of pigeon population control?
The most humane methods of controlling pigeon overpopulation include:
Contraceptive feeding
Adding contraceptive agents like OvoControl to food reduces breeding without harming birds.[41]
Egg replacement
Swapping real eggs with dummy versions prevents hatching and removes incentive to keep nesting.[42]
Nest modification
Installing sloped ledges or grids keeps birds from nesting while allowing roosting.[43]
Live trapping and relocation
Humanely capturing pigeons in cages and releasing to new locations outside the city.[44]
Falconry
Using trained hawks to scare and disperse pigeons avoids need to trap or poison birds.[45]
Habitat modification
Removing food sources, water sources, and nesting sites nudges pigeons to relocate voluntarily.[46]
Avoiding lethal control methods like poisoning preserves pigeon welfare. Cities should first try sustainable, non-lethal management strategies.
What are some best practices for cities managing pigeon populations?
Recommended best practices for cities managing urban pigeons include:
– Work with wildlife experts to humanely reduce large concentrations of pigeons.[47]
– Regularly power wash droppings from building facades, sidewalks, public squares, etc.[48]
– Install deterrents like spikes, nets, and slopes to discourage roosting on structures.[49]
– Contain trash in secure bins and prohibit public feeding to limit food sources.[50]
– Educate the public on safely coexisting with urban wildlife like pigeons.[51]
– Monitor for disease outbreaks and isolate sick bird populations when needed.[52]
– Use pigeon feces responsibly as garden fertilizer once sterilized.[53]
– Evaluate control methods based on humaneness, efficacy, and sustainability.[54]
With an informed, humane strategy rooted in ecology, cities can successfully maintain healthy pigeon populations and minimize problems.
Conclusion
While rock pigeons are often seen as pests, they are an integral part of urban ecosystems that provide some benefits. However, large uncontrolled pigeon populations can negatively impact infrastructure, sanitation, property, and agriculture in cities. Diseases are a minor risk, as pigeons rarely directly infect humans. Effective management relies on deterrents, population control, public education, and finding a sustainable balance between human and avian residents. With informed policies that prioritize animal welfare, cities can humanely resolve issues caused by these highly adaptable birds.
