At day 28 the young have taken over abandoned nests and after about the 30th day they are independent. The juveniles begin fall migration the earliest and continue later than the adults. The adults also vacate the breeding ground as soon as the young disperse. The bank swallows begin breeding after the first summer they are born. The order passeriformes or passerines alludes to the fact that these types of birds are perching birds and possess arboreal habits.
Passerines are the most highly evolved of all birds, and are highly adaptive to terrestrial terrain.
They are found all over the world, except Antarctica. The order Passerine has the largest number of bird species, with over 5,100 different kind. Passerinerines are small land birds with fragile bones. As a result they are rarely fossilized, giving few clues to their evolution. The Hirundinidae family, is the family name the Swallows belongs to, and is also part of the Passerines order.