The enthusiasm with which this bird, the house sparrow of Europe and Asia, has been spread all over the world, despite many warnings about its habits, is difficult to understand. From 1850 to 1870 it was introduced in many places in the United States, Like the starling, it is a prolific, aggressive bird. Its worst fault is that it usurps for its nest holes, cavities and bird boxes that would otherwise be available to more attractive native birds. However, now they are here, we have no choice but to accept them as an integral part of our avian fauna. Any bird that can increase from a few thousand to millions, and spread over a continent in just a few years, clearly enjoys a wide margin of safety between its rate of reproduction and its rate of mortality. It is folly to think that bounties or any other artificial controls can be more than temporarily effective. The moment a local English sparrow or starling population is reduced below a region's carrying capacity for the species, it rapidly builds up again. In recent years, the decline of the horse has materially reduced the English sparrow carrying capacity of both city and country areas. Scientific name: Passer domesticus. Length: 6? inches. Range: Originally Now the temperate zones of every continent in the world.