The House Sparrow, long known as the English Sparrow, was introduced into North America from Europe in 1854. The reasons for its release in Brooklyn have been variously described—regardless, it spread quickly along the Eastern Seaboard and by the 1940s had essentially conquered the continent.
House Sparrows are common inhabitants of urban—and some not-so-urban—areas in the Chihuahuan Desert. Yet, despite their recent arrival, our local birds not only differ markedly from populations of House Sparrows in their Old World homeland, but also from other recently arrived populations spread across North America.
When studied some 110 years after their introduction, House Sparrow populations in various parts of the continent had become as different as populations recognized as subspecies among native birds. Notable differences occurred in darkness of color, in body weight, and in size of such body parts as wings and bills. By looking when the birds had arrived at specific sites, the researchers were able to conclude that such evolutionary changes could occur in as short a time as 50 years.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
House Sparrow. Painting by Louis Agassiz Fuertes, after Henshaw (1921).
Johnston, R. F., and R. K. Selander. 1964. House Sparrows: Rapid evolution of races in North America. Science, 144 (3618):548-550.
