The cheery and sociable house sparrow is more closely associated with humans than any other widely established North American exotic. Introduced to New York City in 1851, the species today flourishes in both large cities and remote agricultural outposts—just so long as there is some trace of human influence. It aggressively defends nest cavities, possibly to the detriment of native species. It is more gregarious in winter. Polytypic. Length 6.3".
Tame; gregarious. Flight more direct, often higher, than native sparrows. Bill thick, conical; legs short; stocky build. One molt per year, but seasonal variation pronounced. Adult male: worn (breeding) male contrastingly marked; throat and breast black, postoccipital and nuchal regions chestnut, wings russet. On freshly molted (nonbreeding) bird, the blackish and reddish regions obscured by gray feather tips. Bill black in summer; yellowish base to lower mandible in winter. Adult female: mainly gray-tan. Buffy eye stripe; gray-brown crown and auriculars. Bill more yellowish than male’s; tip, culmen dusky. Juvenile: variable. Plain overall. Resembles adult female.
The North American population (nominate ssp.) exhibits extensive geographic variation, with clinal variation: larger birds with shorter appendages in colder climes, darker plumages in more-humid environments.
Males distinctive; plainer females and juveniles present a combination of structural and plumage characters that separate them from native sparrows. Flight more resembles the house finch than native sparrows. A female orange bishop may be passed off as female house sparrow by observers unfamiliar with the former.
All vocalizations simple. Call: varied, but 3 notes are prevalent: throaty jigga, usually given by agitated birds; soft chirv, often heard in flight; honest-to-goodness chirp, given in various settings. Song: short series of pleasant chirp notes.
Status and Distribution
Locally abundant. Year-round: cities, farms, and other human-transformed environments. Vagrant: several recs. for western Canada and Alaska, outside current range.
Some Palearctic populations are in sharp decline, possibly due to changing land-use patterns.
—From the National Geographic book Complete Birds of North America, 2006