- Demonstrate ability to educate clients about control options for common nuisance birds.
- Provide a diagram of typical traps used to capture unprotected birds.
- Identify the risks associated with buildings infested by unprotected birds.
Legal Status in New York
NWCOs may take or possess these unprotected birds without any additional permit from the DEC when they are damaging or destroying property, or found to be a nuisance. These birds are exotic, non-native species. An exemption to the Migratory Bird Treaty Act allows for their control without a federal permit. Local ordinances may prohibit certain control measures. However, the law prohibits anyone from capturing, killing or attempting to capture or kill an Antwerp or homing pigeon wearing a ring or seamless leg band. Before initiating control methods, accurately identify the offending species, as they can be confused with protected native species.
Overview of Damage Prevention and Control Methods
- Remove bird feeders
- Discourage public feeding
- Eliminate standing water
- Cut down trees, or trim up to 1/3 of branches
- Close external openings to buildings
- Screen eaves, vents, windows, doors and other openings with ¼-inch mesh hardware cloth
- Exclude nesting sites with wire mesh or netting
- Ledge products – spikes, wire, coils, electric shock
- Propane cannons
- Distress calls
- Mylar-style tape
- Scare-eye balloons
- Long-range acoustic devices
Repellents and Toxicants
In New York, any use of toxicants or repellents by NWCOs requires the NWCO to have a pesticide applicator license.
- .177-caliber pellet guns
- .22-caliber rifles
- Shotgun with No. 7½ shot
- Multiple capture cage traps
- Single-bird traps
- Cannon nets
- Hand-held nets
- Mist netting
Other Control Methods
- Removal of nests
- Falconry (abatement or hazing)
- Remove isolated birds in buildings
- OvoControl® P fertility or reproductive control (pigeons only)
- House sparrow (Passer domesticus)
- European starling (Sturnus vulgaris)
- Pigeon (Columba livia); also known as feral pigeon and rock dove
This module describes the biology and control techniques for 3 species of birds that are not native to the US. As exotics, these 3 species are not protected by the North American Migratory Bird Treaty Act.
House sparrows are the smallest of the unprotected birds at about 6½ inches long and weighing less than an ounce (Figure 1a). Both genders are mostly brown with black streaks above and grayish below. Males have a black throat-bib flanked by white spots. Immature male house sparrows look like females. Do not confuse house sparrows with native sparrows (i.e., chipping sparrow, grasshopper sparrow, song sparrow) that are beneficial and protected by federal and state regulations.
European starlings are robin-sized, short-tailed black birds about 8½ inches long and weigh about 3 ounces. Plumage color changes with gender and season (Figure 1b). In summer, adults are glossy black with light speckles. In winter, birds have larger speckles, making them look browner from a distance. Female starlings typically have less color and more cream on the tips of their feathers. The dark pointy beak becomes bright yellow in spring. Both males and females have pinkish-red color on their legs. Other native “black birds” inhabit the US (e.g., red-winged blackbird) and are protected by federal and state regulations.
Pigeons are the largest of the 3 birds, at about 12 inches long and weigh 12 to 17 ounces. They typically are blue-gray with 2 black bands on the wings and 1 black band on the tail that contrasts with its white rump (Figure 1c). Color morphs range from all white to mottled brown to sooty black. They are larger than the tawny-brown mourning doves that are native to the US and protected by federal and state regulations.
Voice and Sounds
Calls of sparrows are easily identified by a loud and repetitive “chirp.” Calls of starlings are quite diverse as they can mimic the sounds of other birds. Calls of pigeons consist of a soft and throaty cooing.
Tracks and Signs
Figures 2a through 2c represents tracks of house sparrows, starlings, and pigeons. All 3 species are diurnal and comfortable around people, making their presence easy to detect.
Reproduction and Nesting
Nests of house sparrows are messy piles of grasses, string, paper, and twigs that fill a void or crevice where the nest was placed (Figure 3a). Females lay 3 to 9 eggs in a single clutch and can repeat this up to 2 times a year beginning in early April.
Nests of European starlings are less conspicuous and usually associated with a cavity. Sometimes cavities inhabited by starlings can be identified by the fan-shaped spray of feces on the wall below the cavity. While preferring to construct nests in cavities, starlings have been known to construct very large nests as they try to “fill” a void (Figure 3b), something house sparrows also may do. Females lay 4 to 6 eggs per clutch and may nest twice a year.
Pigeons mate year-round, but most of the 5 to 6 broods per year are raised during the spring and summer, when temperatures are above freezing. Nests usually are found on sheltered ledges and consist of sticks and hardened feces (Figure 3c). Females usually lay 2 eggs per clutch but can vary from 1 to 3 eggs.
In winter, starlings form large flocks and cause problems with noise and droppings.
All 3 species use urban and rural environments.
All 3 species prefer to eat grains, but each has its own alternative dietary preferences. Pigeons require access to water (approximately 1 ounce per day) and grit to help them grind their food for digestion. Starlings and house sparrows also use grit but do not require it as often when feeding on insects. Sparrows and starlings eat fruit, seeds, and suet. Both birds increase consumption of insects during the nesting season.
Damage to Structures
Bird droppings are easily noticeable by tell-tale white stains. These droppings are acidic and can deface and accelerate deterioration of building materials. Accumulated droppings can plug the gutters of roofs causing water damage and the weight of droppings can threaten the collapse of ceilings. Nests can obstruct exhaust vents and may cause fires.
Damage to Livestock and Pets
House sparrows and starlings compete with native birds for food and harborage and occasionally kill nesting native birds. They consume livestock feed and contaminate it with feces, raising the risk of disease transmission.
Damage to Landscapes
Starlings can damage turf when they are looking for insects. Dropping-covered sidewalks are aesthetically unpleasing (Figure 4).
Starlings damage cultivated fruits such as grapes, peaches, blueberries, strawberries, figs, apples, and cherries. They also damage ripening corn.
Health and Safety Concerns
Droppings present the risk of disease transmission, as well as being unsightly. In particular, soils contaminated with droppings encourage the growth of the fungus responsible for causing histoplasmosis. While bird droppings provide suitable conditions to grow the fungus that causes histoplasmosis, the birds themselves do not appear to excrete the fungus. (Bat droppings, however, often host the fungus). Accumulated droppings may weaken bridges or other structures by their weight and acidic nature. Around airports, flocks of birds pose the threat of air-strike to airline safety.
All 3 species host infectious diseases, including some that can harm humans, such as encephalitis. House sparrows can carry salmonellosis, psittacosis, and various parasites. Starlings have transmitted encephalitis (through the mosquito as the vector) and ornithosis. Pigeons may spread Newcastle disease and cryptococcosis.
The role of these species in transmitting diseases to humans is not understood as well as it is for livestock. People can reduce their risk of infection by avoiding contaminated areas or by wearing proper protection during bird control and fecal cleanup. Visit http://icwdm.com for information on proper safety guidelines. Although rare, people in areas with active roosts can suffer bites from mites that are associated with the birds.
All 3 species are active during daylight and their presence often is noticeable and annoying to people. Aside from problems with individual birds, large flocks of these birds raise the most ire in urban areas. Problems can range from excessive noise to large quantities of excrement deposited on sidewalks, cars, and buildings. For example, pigeon excrement on gas station canopies can clog downspouts leading to their collapse during rainfall. The acidic nature of bird droppings also degrades marble statues and building materials, potentially threatening structural integrity.
Damage Prevention and
Any of the 3 species can be controlled whenever they become a problem. Take care during periods when flightless young may be present. As invasive species, these birds have negatively affected native bird species through competition for habitat and resources. For example, house sparrows and starlings often destroy the nests of native bluebirds and occasionally kill the adults. Conversely, these birds perform valuable services in removing food waste and/or eating harmful insects. Many people enjoy feeding birds and raising pigeons for fun, racing, and show. Pigeons with leg bands should be considered personal property.
Remove sources of food and water to reduce the attractiveness of the property to birds. Secure trash in covered containers to prevent birds from accessing waste food. Prohibit the feeding of birds on your property and encourage officials to enact local ordinances to ban feeding birds in public areas. Reduce the availability of free water by repairing leaky faucets, clearing drains, and grading surfaces to remove water. Ensure that water from condensers of air conditioners does not pool on roofs or the ground. Angle gutters to permit proper drainage.
Birds are attracted to trees with dense leaf cover and large numbers of branches in the winter. Regular pruning of up to one-third of the branches can discourage birds from using trees as roost sites (Figure 5). Secure the services of a certified arborist for pruning landscape trees. Contact an electric company if trees are near power lines.
A variety of devices are available to prevent birds from perching and otherwise gaining access to structures. This module provides a brief description of the major categories.
Nets with ½-inch mesh will prevent birds from gaining access to a location. The use of nets is labor intensive, but often is the best way to prevent birds from accessing rafters and building frontage that have too many ledges to be managed by ledge products (Figure 6a). Zippers allow nets to be used in areas where access is needed, such as doorways and lights.
Ledge products prevent birds from roosting on flat surfaces. The non-electric products include, spikes (Figure 6b), wires, coils, 45° angle inserts, and specialty products.
Electric-shock products (Figure 6c) may be powered by solar chargers or electrical outlets. When birds land, their feet complete the connection discharging a mild shock, causing them to flee.
Several devices are available that employ audible and/or visual stimuli to frighten birds. Frightening is most effective when a variety of tactics are used before birds have habituated to a site. Frightening rarely provides long-term reduction in damage as birds often become acclimated to devices that do not change over time. Vary the timing, placement, and selection of frightening devices.
A wide variety of tools are available, such as distress calls, Mylar® tape (Figure 7), Mylar® balloons, scary-eye balloons, predator kites, and owl effigies.
Shell crackers and other pyrotechnics are among the most effective of the devices. However, the explosive nature of these projectiles limits their use in urban areas. Always consult local authorities before using pyrotechnics. Avoid ultrasonic devices, as no reliable evidence indicates that they are effective. A Long Range Acoustic Device (LRAD) projects a high-decibel sound up to 153 dB out to 200 to 300 yards. The further animals are from the source of the sound, the lower the decibel level. The LRADs are useful for hazing birds out of trees or off of surfaces.
Repellents and Toxicants
In New York, any use of toxicants or repellents by NWCOs requires the NWCO to have a pesticide applicator license.
Before using any product, you must check the New York State Pesticide Administrator Database (NYSPAD) to see if the product is registered for use in NY and for the target species. For example, if the product is registered for use on squirrels, it cannot be used for deer. The following are presented as examples of repellents and toxicants that may be effective.
Tactile repellents such as sticky gels (polybutenes) can be used to prevent birds from perching on ledges and other horizontal surfaces. Avoid applying gels directly to surfaces, as they can be difficult to remove. Instead, cover surfaces with wood, plastic, or tape and apply gels on the temporary surface. Repellents that are protected from blowing dust and dirt maintain their repellency for a longer period. Follow product labels carefully as over-application can trap small birds that land on the gel. Even pigeons can be “grounded” if the gel gets into the flight feathers. Be sure non-target birds are not likely to come in contact with the repellent. Choose gels suitable for temperatures above 110°F when treating sun-exposed ledges. Check with the DEC Bureau of Pest Management for more information on these repellents.
Methyl anthranilate (MA) can disperse birds from large spaces such as warehouses when applied with a fogger. Methyl anthranilate (MA) is an oil-based chemical derived from grapes that irritates birds. In sufficient concentrations, the repellent is effective in dispersing all species of birds. It is most useful for dispersing birds roosting in trees and in confined areas, such as hangers, warehouses, and electrical substations. Methyl anthranilate is believed to pose little risk to humans and has been used as a food additive and flavoring in processed foods for decades. It leaves a lingering grape odor. Use a thermal fogger to rapidly disperse birds roosting in trees and open areas. Use cold foggers and haze generators for long-term control inside buildings and areas where a buildup of MA on surfaces would present a hazard of slipping for employees.
Avitrol® is classified as a chemical frightening agent for birds, and it is a registered pesticide. The active ingredient is 4-aminopyridine. Birds that eat treated pellets act erratically and emit distress signals to other birds, causing them to flee. Death usually follows for those birds that eat the treated bait. Due to the risk of Avitrol® to protected birds, only certified pesticide applicators can purchase and apply the product. A series of procedures must be followed when using Avitrol®, including pre-baiting and removal of bait if non-target birds are observed in the area. Do not use Avitrol® as a toxicant. The behavior of treated birds can be quite disturbing to onlookers, though research suggests that treated birds are not in physical pain. Nevertheless, applicators should choose locations, bait concentrations, and time of treatments to reduce potential negative public reaction. Although the risk of secondary poisoning is quite low, dead birds should be picked up, placed in a plastic bag, and disposed of with regular municipal waste. Avitrol® cannot be used in all areas, so check state and local pesticide regulations.
Starlicide™ Complete (DRC-1339) is an avicide developed for starling control. Treated birds experience kidney failure and hypothermia. They usually die within 1 to 3 days after feeding at their evening roost. Due to the delay in mortality, the toxicant is metabolized and scavengers are unlikely to experience secondary poisoning. Dead birds should be picked up at roost sites and disposed of properly to reduce negative public reaction. Dispose of birds by incineration or burial at least 2 feet underground and 200 feet from sources of water. DRC-1339 is a restricted use pesticide that can only be purchased and applied by USDA-APHIS certified applicators trained in bird control or persons under their direct supervision.
Populations of problem birds can be reduced immediately through shooting. Use .177-caliber or .22-caliber rifles. Shoot at night, when the birds are roosting, as several birds can be shot before the remaining birds become startled and leave. Shotguns with No. 7½ shot are useful when controlling large flocks or when birds are in flight. Birds do not have to be shot at the site of the problem. Check local ordinances before shooting. Always follow shooting safety guidelines and regulations.
Traps (Figure 8a) provide an excellent form of control in situations where other methods are not feasible or there is risk of harm to protected species.
Traps range from single-capture devices to multiple-catch traps capable of capturing dozens of birds. Place traps where birds can see them easily, such as rooftops and raised platforms. When trapping large flocks, improve success by leaving a few decoy birds inside multiple-catch traps to lure others. Provide food and water for decoy birds and protect them from the elements. Check traps daily.
Use of nest-style traps (Figure 8b) can be effective for sparrows and starlings inside structures.
Cannon nets are used in open areas such as parking lots or fields to capture birds. Nets may be propelled by rockets or compressed air. Use hand-held nets, propelled by compressed carbon dioxide, to capture individual birds.
Mist nets are used to capture birds in flight. These nets are made with thin fibers and thus difficult for birds to see and avoid when suspended in flight paths. Nets must be used with care to prevent harm to birds as they struggle against the net. Obtain appropriate training before using nets to capture nuisance birds.
In rescue situations (e.g., from chimneys or basements), birds can be released on-site, provided the entrance has been secured properly.
Relocation and Translocation
Translocation of pigeons is not allowed in New York. Pigeons can fly hundreds of miles and return to the original flock. Translocation of sparrows and starlings is not practical.
Carbon dioxide is the preferred method of euthanasia. All birds expire relatively quickly in a carbon-dioxide environment. Cervical dislocation is another option for euthanasia for staff with training and experience. Grasp the bird firmly in one arm, and with the other grasp its head between thumb and index finger. Pull and twist in a quick jerk to break the neck.
Check state and local regulations regarding disposal of carcasses.
Other Control Methods
Nest and Egg Removal
The nests of house sparrows and pigeons are conspicuous, and often can be removed easily to reduce reproduction in these problem species. Nests of starlings typically are in cavities and are much less obvious. The nests, eggs, young, and adults of these species are not protected by federal law. Use a ladder or a long pole with a hook at the end to reach nests that are high off the ground. Always use caution when setting and climbing ladders and reaching for nests, especially near overhead wires. To avoid contact with nest mites and lice, use gloves and place nesting material and eggs in a plastic bag for disposal. If young chicks are present, quickly euthanize them with carbon dioxide, cervical dislocation, or thoracic compression. Details on euthanasia can be found in module 10 and at http://icwdm.com. Most pest birds are quick to rebuild nests, often in the same location, so block access to the nest site or be persistent and prepared to remove nests and eggs repeatedly from spring through fall.
Falconry-based Bird Abatement
Raptors (Figure 9) have been used to frighten birds from larger areas such as airports. At harvest time, invading flocks of pest birds can decimate crops, especially grapes, blueberries, and cherries. Falconry can scare pest birds more effectively than shotguns, visual deterrents, or noisemakers. This method is chemical-free and non-polluting. Perch poles and nest boxes to attract raptors have not been proven to be effective.
While the presence of hawks or falcons immediately disperses birds, long-term control can only be achieved by regular visits by a falconer. Abatement falconry describes a traditional falconer using specific falconry techniques for the purpose of pest management. Unlike raptors trained for sport or hunting, abatement raptors are trained to haze instead of kill birds. This method can be expensive due to repeated site visits. Few falconers are available with birds trained for pest management.
Lone Bird in Structure
Birds sometimes get inside buildings and are unable or unwilling to leave. These situations can be quite difficult to resolve, particularly when in a public place such as big-box stores and supermarkets. If possible, restrict the area where the bird can fly. Birds tend to fly toward light, so darken the area except for the exit to encourage a bird to fly in the right direction. The use of hand nets may work, but the bird is often able to fly around it. Mist nests can be very effective but require regular monitoring to prevent bird deaths. In many circumstances, trapping or shooting will be the only viable options.
Fertility or Reproductive Control
OvoControl® P is an oral fertility (reproductive) control agent that prevents pigeon eggs from hatching, thereby interrupting the reproductive cycle. Female pigeons that consume 1/5 ounce of bait per day are effectively sterilized as long as they continue feeding on the product. Reports indicate that populations treated with OvoControl® P decline by approximately 50% annually under typical conditions. One pound of bait treats 80 birds per day. Labor costs can be reduced by installing low-cost, automatic feeders. Fertility control should be considered only in situations that do not require an immediate and dramatic reduction in the number of pigeons. Large sites with multiple structures and high concentrations of pigeons generally are the best candidates. OvoControl® P can be combined with trapping and shooting if an immediate population reduction is required. OvoControl® P is a regulated pesticide in New York.
This material was adapted and updated from the book, Prevention and Control of Wildlife Damage, 1994, published by the University of Nebraska–Lincoln Extension.
Reviewers of Original Document
- Michael Beran, All Animal Control of Northwest Louisiana;
- Lynn Braband, Cornell University