ABSTRACT
During the mid-1800s, the house sparrow (Passer domesticus) became an unwitting participant in a global phenomenon of species redistribution. House sparrows, native to much of Europe and northern Asia, were deliberately introduced to such far-flung places as North America, Australia, South America, and Hawaii (Long 1981). Today, house sparrows occupy every continent on Earth except Antarctica; and given global warming trends, they may eventually find themselves there, particularly along the Antarctic Peninsula where summer temperatures can rise above freezing. House sparrows were introduced to various locations via the earnest attempts of humans to surround themselves with familiar species, or in an effort to use house sparrows to control agricultural pests. There is some evidence that house sparrows were also introduced to locations as accidental stowaways on oceangoing ships and trains, which is a reasonable assumption given the sparrow's propensity to nest in the nooks and crannies of human habitations, including ship decks and rigging, and to forage near human infrastructure, including grain transport railcars (Summers-Smith 1963; Anderson 2006). Given their ubiquity, and the occasional concern they generated in terms of their agricultural damage, researchers began compiling information on house sparrow introduction dates, geographical range expansions, and local and rangewide physiological, morphological, and behavioral adaptations. As a result of this intense research focus, house sparrows have provided a staggering amount of information on the mechanisms driving contemporary evolution, as well as the conditions that facilitate successful invasions. Here we focus on their impacts to native species, human economies, and health, as well as on the varied efforts to control or mitigate these impacts.
