The most common roosting birds in cities and suburbs are pigeons, European Starlings and House Sparrows. All are highly adaptable, and very capable of finding shelter and roosting sites on and in buildings. They eat food from garbage cans and bird feeders, and in parks where people offer them handouts.
Pigeons, also known as Rock Pigeons, were introduced into North America in 1606. They nest under bridges, inside barns, and on building ledges, rafters, and beams. They lay eggs throughout the year and raise several broods of one or two young, who can fly about 35 days after hatching.
Rock Pigeons were the first birds domesticated by humans, raised for food and used later as message carriers. Wild, city pigeons are feral descendants of domesticated Rock Pigeons.
The European Starling was introduced in New York in 1890 and has since spread across the continent. In spring, the starling's plumage is black with iridescent tints of green and purple, and the bill is yellow. In winter, the bill is dark and the plumage is lighter and speckled.
Starlings often roost in large numbers, and during fall and winter they flock to and from their communal night roosts. They nest in cavities, including holes in freeway signposts, and they compete aggressively for nest holes in trees with native birds such as flickers and bluebirds.
Starlings raise two to three broods per season, each with four to six young who usually leave the nest 21 days after hatching. Known for their diverse vocalizations, starlings can imitate the sounds of other birds and animals.
The House Sparrow was introduced to North America in the mid-19th century and now lives throughout the United States. The male has a brown back and wings, pale gray underparts, and a black bib. The female has a solid grayish-brown breast and no black markings.
House Sparrows always live close to humans, and are frequently seen in large flocks in city trees and hedges, or under the eaves of buildings, where they build their nests. They raise two or three broods during the spring and summer, each with three to seven young. The youngsters leave the nest at about 17 days after hatching.
Solving and preventing conflicts
Roosting birds, like pigeons, starlings and sparrows, rarely cause damage, but when they gather in large numbers their droppings can get messy and unsanitary. Habitat modification can keep birds out of areas where they are not welcome.
Bird-proofing with netting
Bird netting made of weather resistant material is available in a variety of sizes and is a versatile tool for bird-proofing. To prevent birds from roosting on window ledges, anchor the netting to the roofline, stretch it across the front of the building, and secure it at the bottom and sides.
You can overlap large panels of netting and hang them in front of a garage or other open door. Netting can also be used inside buildings to prevent perching on rafters and other horizontal surfaces.
- To keep pigeons off flat surfaces, such as ledges, you can modify the surface. Make a false ledge by fastening wood, stone, or metal over the surface, angled, at least 60 degrees. The birds will slide off when they land.
- Use parallel lines of monofilament line or stainless steel wire to make a barrier. String the lines through eyelet screws a few inches above the roosting surface. Keep the lines taut by placing the eyelets no more than 18 inches apart.
- To prevent starlings and sparrows from nesting in buildings, seal holes under eaves and in outside walls and replace loose shingles and siding. If the birds have already nested and are caring for babies, wait until the young have fledged and left the nest, then remove all nesting materials and close openings.
- If you put up nesting boxes in your yard, choose ones with small openings that accommodate chickadees, nuthatches, and wrens. Boxes with holes larger than 1 inch in diameter fit starlings and sparrows, therefore you should avoid them if you do not want to attract these birds.