Passer is a genus of sparrows, also known as the true sparrows. The genus contains 28 species and includes the house sparrow and the Eurasian tree sparrow, two of the most common birds in the world. They are small birds with thick bills for eating seeds, and are mostly coloured grey or brown. Native to the Old World, some species have been introduced throughout the world.
Passer
A mixed group of Passer sparrows containing a Eurasian tree sparrow, a male house sparrow, and female house or Spanish sparrows, feeding on grain in the town of Baikonur, Kazakhstan
Image: Cape Sparrow, Passer melanurus at Walter Sisulu National Botanical Garden, Johannesburg, South Africa (14727921265)
Image: Kambi ya Tembo, Tanzania 2nd. September 2012 CF2P1407 Flickr Lip Kee
Old World sparrows are a group of small passerine birds forming the family Passeridae. They are also known as true sparrows, a name also used for a particular genus of the family, Passer. They are distinct from both the New World sparrows, in the family Passerellidae, and from a few other birds sharing their name, such as the Java sparrow of the family Estrildidae. Many species nest on buildings and the house and Eurasian tree sparrows, in particular, inhabit cities in large numbers. They are primarily seed-eaters, though they also consume small insects. Some species scavenge for food around cities and, like pigeons or gulls, will eat small quantities of a diversity of items.
Old World sparrow
Male house sparrow in Germany
Yellow-throated sparrow at Keoladeo National Park, India
Sparrow in Tharparkar, Sindh