Weaver Finches

The typical weaver finches are in the genus Passer, including two species that commonly nest in cities and around farms in many regions—the house sparrow (Passer domesticus) and the Eurasian tree sparrow (P. montanum). Both of these species have been introduced far beyond their original, natural ranges. This includes North America, where the house sparrow in particular is a common bird in cities. In fact, the house sparrow is now one of the world's most widely distributed species of land birds.

The village weaver (Ploceus cucullatus) of African savannas is a colonial nester, with many pairs of birds building individual, pendulous nests from the same tree. The social weaver (Philetarus socius) is also a colonial nester. However, this species builds an aggregate, apartment-like nest, comprised of large numbers of arboreal hanging nests constructed immediately adjacent to each other, so that the finished mass looks rather like a haystack. The entrance holes to the individual compartments are on the underside of the mass, so that entry requires a brief hover.

The snow finch (Montifringilla nivalis) is a species existing in alpine tundra in Europe and Asia.

One of the most spectacular weaver finches is the paradise widowbird or whydah (Steganura paradisea), which breeds in savannas of tropical Africa. Males of this polygynous species achieve a length of 13.4 in (34 cm), of which about 3/4 is due to their fabulously long tail, comprised of three or four over-developed, black feathers. This attractive bird also has a black face and back, a chestnut breast, a yellow nape, and a whitish belly. Female paradise widowbirds are relatively drab, brownish-and-whitish birds.

Field studies have shown that paradise widowbird males with the longest tail are more successful in attracting females. In part, this was demonstrated by clipping the tail of some individuals. These truncated fellows were then considerably less fortunate in their love life than males who had not been tampered with, or had their tail cut, and then glued back on. This is an example of sexual selection, in which traits that may be detrimental in some respects, for example, in foraging or escaping from predators, may nevertheless be selected for because they enhance reproductive success. In this case, the extraordinarily long tail of male paradise weaverbirds is favored by sexual selection, because a long tail has an irresistible appeal to females.

Some other weaver finches also have long tails, for example, the queen whydah (Vidua regia), and the pintailed weaverbird (Vidua macroura), both of tropical Africa.