Song Sparrow

Appearance

Adult song sparrows have brown upperparts with dark streaks on the back and are white underneath with dark streaking and a dark brown spot in the middle of the breast. They have a brown cap and a long brown rounded tail. Their face is grey with a streak through the eye. They are highly variable in size across numerous subspecies. The body length ranges from 11 to 18 cm and wingspan can range from 18 to 25.4 cm. Body mass ranges from 11.9 to 53 g,. The average of all races is 32 g but the widespread nominate subspecies weighs only about 22 g on average. The maximum lifespan in the wild is 11.3 years.

In the field, they are most easily confused with its congener the Lincoln's Sparrow, and the Savannah Sparrow. The former can be recognized by its shorter, greyer tail and the differently-patterned head, the brown cheeks forming a clear-cut angular patch. The Savannah Sparrow has a forked tail and yellowish flecks on the face when seen up close.

Naming

The Song Sparrow is one of the birds with the most numerous subspecies in North America, and even on a global scale rivals such species as the Horned Lark, the Yellow Wagtail, the Golden Whistler or the Island Thrush; 52 subspecies were named altogether, of which 24 are considered valid nowadays. It is a cryptic species.

Distribution

Although they are a habitat generalist, their favorite habitat is brushy areas and marshes, including salt marshes, across most of Canada and the United States. They also thrive in human areas, such as in suburbs, along edges in agricultural areas, and along roadsides. In southern locations, they are permanent residents. Northern birds migrate to the southern United States or Mexico, where there is also a local population resident all year round. The song sparrow is a very rare vagrant to western Europe, with a few recorded in Great Britain and Norway.

These birds forage on the ground, in shrubs or in very shallow water. They mainly eat insects and seeds. Birds in salt marshes may also eat small crustaceans. They nest either in a sheltered location on the ground or in trees or shrubs.

Status

Seen as a whole, the Song Sparrow is widespread and common enough to be classified as Species of Least Concern by the IUCN. The taxa "mailliardi", "maxillaris", "samuelis", "pusillula", and "graminea" are listed as Species of Special Concern in California.

Reproduction

The song sparrow lays 3–5 eggs.
The egg coloring is a brown spotted greenish-white.

Predators

Common predators of the Song Sparrow include cats, hawks, and owls. Snakes, dogs, and the American Kestrel are treated ambiguously, suggesting that they are less of a threat. The Song Sparrow recognizes enemies by both instinctual and learned patterns, and adjusts its future behavior based on both its own experiences in encounters, and from watching other birds interact with the enemies. Comparisons of experiments on hand-raised birds to observation of birds in the wild suggest that the fear of owls and hawks is instinctual, but fear of cats is learned.

Song Sparrows' nests are parasitized by the Brown-headed Cowbird. The cowbirds' eggs closely resemble Song Sparrows' eggs, although the cowbirds' eggs are slightly larger. Song Sparrows recognize cowbirds as a threat and attack the cowbirds when they are near the nest. There is some evidence that this behavior is learned rather than instinctual. A more recent study found that the behavior of attacking female cowbirds near nests may actually attract cowbird parasitism because the female cowbirds use such behavior to identify female Song Sparrows that are more likely to successfully raise a cowbird chick. One study found that while cowbird parasitism did result in more nest failure, overall there were negligible effects on Song Sparrow populations when cowbirds were introduced to an island. The study pointed to a number of explanatory factors including Song Sparrows raising multiple broods, and Song Sparrows' abilities to raise cowbird chicks with their own.

Evolution

Although they are a habitat generalist, their favorite habitat is brushy areas and marshes, including salt marshes, across most of Canada and the United States. They also thrive in human areas, such as in suburbs, along edges in agricultural areas, and along roadsides. In southern locations, they are permanent residents. Northern birds migrate to the southern United States or Mexico, where there is also a local population resident all year round. The song sparrow is a very rare vagrant to western Europe, with a few recorded in Great Britain and Norway.

These birds forage on the ground, in shrubs or in very shallow water. They mainly eat insects and seeds. Birds in salt marshes may also eat small crustaceans. They nest either in a sheltered location on the ground or in trees or shrubs.