Passer is a genus of Old World Sparrows. Most of its members are found naturally in open habitats in the warmer climates of Africa and southern Eurasia. Several species have adapted to human habitation, and this has enabled the House Sparrow in particular, invariably in close association with man, to extend its Eurasian range well beyond what was probably its original home in the Middle East.
The House Sparrow has been introduced to many parts of the world outside its natural range, including the Americas. The Tree Sparrow has also been artificially introduced on a smaller scale, with populations in Missouri and Illinois in the United States.
They are plump brown or greyish birds often with black, yellow or white markings, and with short tails and stubby conical beaks. They are gregarious and will form substantial flocks, and some, though not the House Sparrow, have pleasant songs.
Passer sparrows are primarily ground-feeding seed-eaters, though they also consume small insects especially when breeding. A few species like the House Sparrow scavenge for food around cities, and are almost omnivorous.
