White-tailed KiteElanus leucurus
As recently as the 1940s, this graceful hawk was considered rare and endangered in North America, restricted to a few sites in California and Texas. In recent decades, it has increased greatly in numbers and spread into many new areas. It is often seen hovering on rapidly beating wings over open fields, looking for small rodents, its main food source. The introduction of the house mouse from Europe may have played a part in its increase; formerly, the kite fed almost entirely on voles.