Perching Birds: Passeriformes

The order of Passeriformes, commonly called passerines (PASS-ur-eenz), are the largest and most unique family of birds. A few of the many birds in the passerine order are crows, finches, flycatchers, nightingales, swallows, tanagers, vireos, shrikes, wrens, and warblers. They are sometimes called "perching birds" and (less accurately) "song birds." These perching birds include some of the most colorful and mysterious of all birds in the world, such as birds of paradise from New Guinea and the bright orange cock-of-the-rock from tropical South America. They are generally small to medium in size (except for the crows, jays, and lyrebirds) with large wings relative to their body size. Two interesting physical features of the passerines are their distinctive syrinx (SIHR-ingks; or vocal organ) that allows them through complicated muscles to have a wide range of songs and calls, and their very specialized feet and legs that allow them to grip and move in very unique ways.

Passerines have three toes that point forward and one toe that points backward. The first toe, called the hallux (HAL-lux), is often called the hind toe because it always points backward and is never reversible. This arrangement allows them to perch on many different slender structures such as tree branches, grasses, telephone and fence wires, feeders, or anything that has some type of narrow place to perch. Their vocal organ allows the birds to produce a large range of vocalizations (although some species can only grunt and hiss while others produce very complex and melodic sounds that are called songs).

Bills on passerines vary greatly in size and shape due to the type of diet of each species. The types of bills range from tiny, needle-like bills of insect-easting warblers and vireos, to the generally huge, vise-like bills of finches, designed to crack the hard shells of seeds.

Passerines weigh between about 0.18 ounces (5 grams) in kinglets (also very small in weight are the bushtits and pygmy tits) to about 3.1 pounds (1.4 kilograms) in ravens and about 3.7 pounds (1.7 kilograms) in Australian lyrebirds and ravens.