The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The term "swallow" is used as the common name for Hirundo rustica in the UK and Ireland. Around 90 species of Hirundinidae are known, divided into 19 genera, with the greatest diversity found in Africa, which is also thought to be where they evolved as hole-nesters. They also occur on a number of oceanic islands. A number of European and North American species are long-distance migrants; by contrast, the West and South African swallows are nonmigratory.
Swallow
The bill of the sand martin is typical for the family, being short and wide.
The lesser striped swallow is a partial migrant within Africa.
A Northern Rough-winged Swallow photographed in central Maine, the northeastern limit of the species' breeding range.
A passerine is any bird of the order Passeriformes which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes, which facilitates perching.
Passerine
Pterylosis or the feather tracts in a typical passerine
Male superb lyrebird (Menura novaehollandiae): This unique songbird shows strong sexual dimorphism, with a peculiarly apomorphic display of plumage in males.
Wieslochia fossil
