Most of us have seen small brown birds that flit from the ground to a bush or tree just as you start to look at them; they are common in parks and at bird feeders throughout Alameda — but the description fits more than one species of birds. One of those six-inch birds is the House Sparrow, an immigrant from Europe. They were first brought to Brooklyn, New York, from England in 1851. Soon after, they were deliberately introduced to a few other parts of the country and have now spread throughout the United States. They are also found in South America and South Africa.

The male House Sparrow sports a brown back with darker splotches, grey forehead, grey or cream-colored belly and checks, with a dark patch below its bill, like a bib, and a dark line from its bill to its eye, while the female’s forehead is light brown like her back, and she has neither the black line to her eye nor the black bib. Both have a plain grey belly.

In the early spring, you can watch these industrious birds slip into a dense bush with a piece of grass or a twig in their fat bills — material for the nest being built in the bush. In addition to bushes, they build nests in nooks and crannies, under terracotta roof tiles, nest boxes (often those built for Western Bluebirds) and the palm trees that line some streets. The male starts the nest with twigs and leaves and the female often adds a softer lining. The male strongly defends a small area around the nest from other House Sparrows as well as other birds. The female lays up to five eggs and incubates them for about 12 days. Then both parents feed and guard the chicks, which are born without feathers but quickly reach adult size and grow flight feathers. They leave the nest in about two weeks, after which the parents may start a second and then a third brood.

While this sounds like the population of House Sparrows could quickly overwhelm us, only about 20 percent of the chicks survive the first year. Their main predators are hawks, cats, dogs, raccoons, and snakes, one reason to keep cats indoors.

House Sparrows usually eat seeds and insects, developing buds and fruit when it’s available, which is why we see them hopping on the ground or moving in bushes or on tall grasses. They also eat household scraps and have been known to steal food from other birds. Insects are a specially important food for chicks.

Often heard before they are seen, House Sparrows “cheep” to each other to maintain contact as they search for food. Males “cheep” to announce their territory and guard their nest location. While bird guidebooks describe their sounds as “cheep,” it often sounds like a harsh “chew, chew.”

While the species has spread across the country, first to farms and now to urban areas and suburbs, most House Sparrows spend their lives close to where they were hatched. However, as winter weather sets in, some birds that breed in the mountains may move to lower locations until spring, and some young birds may explore a short distance from their hatch area until they select an area in which to settle.

Next time you walk in your yard, down the street, or in an Alameda park, pay attention to the little brown birds and see if you can identify a House Sparrow, and then whether you can tell the male (with the black bib) from the female (without the bib but with a light brown forehead).