Male House Sparrow have black throats and chest patches, light cheeks and brown nape. The female has a plain brownish chest and dull eye-stripe.
The House sparrow is the number two urban pest bird. Introduced as a species to North America, the house sparrow quickly spread across the country due to its lack of natural enemies and its adaptive traits. Its ability to nest in urban structures, eat urban scraps and a large breeding capacity are some of these adaptive traits. The House Sparrow is actually a member of the weaverbird family and not a true Sparrow. Weaverbirds create intricate nests and relative to their size, the largest nests in the bird world. Their legs and toes are favored for branch perching and their short conical bills are ideal for seed cracking. Their diet consists of seeds and grain, as well as fruits, vegetables, human table scraps and insects. They are boisterous, intelligent birds who roost in noisy flocks on branches of city trees, ivy covered walls and under eaves of houses.
Damage House Sparrows are often a nuisance in urban areas like manufacturing and food processing plants. Gutters and drainage pipes clogged with sparrow nests can backup and cause extensive water damage and fires have been attributed to electrical shorts casued by machinery housing sparrow nests. Lastly, feces buildup can lead to structural damage from the uric acid in droppings, plus the bacteria, fungal agents and parasites in the feces also pose a serious health risk.
The most effective method of control is to exclude sparrows from the area with 3/4" netting making sure there are no gaps or crevices for the birds to pass through. The only ledge deterrent systems that are truly effective against sparrows are electrified ledge systems that use an intermittent pulse like bird shock. are quite effective at trapping small quantities of sparrows. The best trap has an elevated second chamber that keeps the birds happy and so content that they actually sing, attracting others to the trap. When practical, the trapping program should be combined with a nest removal program that will greatly reduce the population over time. Along with trapping, mist nets can be installed in the flight paths by certified personnel to capture these birds in enclosed areas. A new technique that has found some success for moving populations is to fog problem areas with fog force. This method is most commonly applied when sparrows gather in flocks. Sparrows generally do not react to audio and visual products except occasionally in areas to which they are not very committed (new to area).
They build large nests relative to size which function as the center of all activity. They prefer small enclosed places such as house shutters, drainage piping, building rafters and corrugated metal siding. They will build a spherical nest in a tree or another exposed place if they have no other option. The building material will be sticks, with an inside lining of grass, string, fabrics or straw. The nest will often hold several families.
House sparrows only mate for a season. They average three broods per mating season with each brood containing four to seven eggs with 20 offspring a year average. Egg coloration will be white, pale blue or pale green with a few gray or brown dots. If unchecked, a breeding pair can grow to over 2,000 birds in two to three years.
House Sparrows are not migratory, but in cold climates can show movement between rural/suburban breeding sites and warmer winter roosting sites in the city. House Sparrows are aggressive birds and will often force out other birds from their territories. They are flocking birds and will gather in the thousands to take over feeding and roosting areas.