In 1870, twelve Eurasian tree sparrows (native to Eurasia) were released in St. Louis, Missouri in an effort to provide familiar sights and sounds for homesick European immigrants. The species' population has been spreading and can be found in portions of Missouri, Iowa, and Illinois. Eurasian tree sparrows can easily be mistaken for house sparrows. Eurasian tree sparrows have a rust colored crown, a black ear patch, and a white collar. Male house sparrows have a gray crown and no ear patch or white collar.
