Nuisance Birds and Their Control
Birds generally considered “nuisance birds” include pigeons (Columba livia), house sparrows (Passer domesticus), and starlings (Sternus vulgaris).
The presence of these birds in unwanted areas can cause damage to property, and their droppings may create unpleasant odors. Bird droppings can also ruin vegetation, painted surfaces, gutters and awnings, and cause electrical equipment to malfunction. Birds may carry diseases which are capable of infecting humans, and bird droppings can promote soil conditions favoring development of such fungal diseases as histoplasmosis. House sparrows can damage rigid foam insulation, and their nests can become fire hazards.
The first step in your bird control program should be identification of the pest bird; if you cannot positively identify the bird, consult an expert before taking action. The Migratory Bird Treaty and Endangered Species Acts prohibit trapping or killing of most birds, eggs or nests without a permit. House sparrows, starlings, and pigeons are not protected under these Acts, but may be covered under local ordinances, so be sure to consult with local wildlife authorities.
Suggested Action Thresholds
- droppings one inch deep or more
- nests obstructing equipment, gutters or other areas
- 10 or more animals per building on 3 successive inspections
Habitat modification and exclusion from structures are generally the most effective ways of controlling nuisance bird populations. Note where birds are roosting, nesting, and landing; look for nests and droppings. Eliminate potential food and water sources if possible.
If you are attempting to clean up an existing bird problem, be sure
to clean up all dirt, nests, and bird droppings prior to installing any bird control devices or deterrents; this will not only give a clean surface for installation/application, but will prevent pest birds from reusing nest material or following their own scent trails back to old roosting sites.
Since bird droppings can harbor parasites, bacteria, and disease causing organisms, a thorough cleaning will also help protect those who will be installing bird control devices or deterrents. Be sure to wear protective clothing (face mask, gloves, coveralls) if cleaning up a large accumulation of wastes, and be sure to launder protective clothing separately.
Mechanical or Structural Control Methods
- for window ledges, a ledge made of wood, plexiglass, or stone can be made; be sure to place at 45 degree angle to prevent perching, and be sure ends are closed as well.
- thin wires strung taut between two short posts, and installed at varying heights spaced a few inches apart on the ledge can discourage landing on ledges
- porcupine wire can be used not only on ledges, but also on rafters or windowsills
- two or more rows of wire may be needed
- recommended screen or net mesh sizes are:
- 3/4 inch for sparrows
- 1 1/8 inch for starlings
- 2 1/2 inch for pigeons
- pigeons can be kept off of beams, pipes, or support lines by installing a taut line of piano wire an inch above the surface
- signs should be attached directly to buildings with no space behind for birds to roost, existing signs can be blocked using screens
- eaves may need to be screened
- spaces between window units and buildings should be blocked to keep out sparrows
- use 1-inch uv-stabilized polypropylene netting to protect ornamental architecture from roosting birds
- intake vents, dormer covers, soffits, exhaust fan ductwork, and sparrow and starling nest entry holes in hollow posts may all be screened using 1/2 inch mesh hardware cloth
Interiors or Enclosed Area
- screen undersides of rafters with nylon netting, (cut velcro-attached panels into the netting to allow access to service equipment in the rafters)
- for enclosed courtyard areas, an overhead monofilament grid (1×1 foot) may help exclude pigeons
Polybutylene repellents can be applied to ledges or beams to prevent roosting. These repellents are non-toxic, but feel sticky and unpleasant to birds attempting to land. Apply repellent in tight wavy closely-spaced rows. Repellents must be reapplied with some frequency as they can become coated with dust or leaves and lose their sticky feel. Apply masking tape to the surface prior to using the repellent so that it may be more easily cleaned up and reapplied. Repellents are best suited for small- or medium- sized infestations.
Miscellaneous Control Methods
Ultrasonic devices have not been found to be effective at repelling birds. Noise or visual alarms are not well-suited for urban areas, but may work fairly well in agricultural settings; pigeons in particular are so used to loud noise and varied human activity that they may be nearly impossible to frighten using these methods. Noise alarms in well-populated areas may be perceived as a bigger nuisance than the birds.