Figure 1. House sparrow, Passer domesticus. Male (left) and female (right).

Identification

The house or English sparrow (Fig. 1) is a brown, chunky bird about 5 3/4 inches (15 cm) long, and very common in human-made habitats. The male has a distinctive black bib, white cheeks, a chestnut mantle around the gray crown, and chestnut-colored feathers on the upper wings. The female and young are difficult to distinguish from some native sparrows. They have a plain, dingy-gray breast, a distinct, buffy eye stripe, and a streaked back. The black bib and chestnut-colored feathers on the wings are the first signs of male plumage and appear on the young birds within weeks of leaving the nest.

General Biology, Reproduction, and Behavior

Breeding can occur in any month but is most common from March through August. The male usually selects a nest site and controls a territory centered around it. Nests are bulky, roofed affairs, built haphazardly and without the good workmanship displayed by other weaver finches, the group to which the house sparrow belongs. Sparrows are loosely monogamous. Both sexes feed and take care of the young, although the female does most of the brooding. From 3 to 7 eggs are laid, 4 to 5 being the most typical. Incubation takes 10 to 14 days, and the young stay in the nest for about 15 days. They may still be fed by the adults for another 2 weeks after leaving the nest.

House sparrows are aggressive and social, both of which increases their ability to compete with most native birds. Sparrows do not migrate. Studies have shown that 90% of the adults will stay within a radius of 1 1/4 miles (2 km) during the nesting period. Exceptions occur when the young set up new territories. Flocks of juveniles and nonbreeding adults will move 4 to 5 miles (6 to 8 km) from nesting sites to seasonal feeding areas.

Mortality is highest during the first year of life. Few sparrows survive in the wild past their fifth season. One individual, however, lived in captivity for 23 years. While house sparrows are tolerant of disturbance by humans, they can in no way be considered tame. Their success lies in their ability to exploit new habitats, particularly those influenced by humans.