any of about 40 species of small to medium-sized forest birds (order Passeriformes). They are rivalled only by a few pheasants and hummingbirds in colour and in the bizarre shape of the males' plumage. Courting males perform for hours on a chosen perch or in a cleared space (see lek) on the forest floor. After mating, the plain females generally make the nest and raise the one or two young unaided.

Birds-of-paradise occur in New Guinea highlands and on nearby islands; species called manucodes (manucode) and riflebirds (riflebird) are found also in Australia. The largest manucode is the 45-centimetre (17 ¹/₂-inch) curl-crested manucode (Manucodia comrii). The trumpetbird (Phonygammus keraudrenii) is 25 to 32 cm (10 to 12 ¹/₂ in.) long and has head tufts as well as pointed neck feathers. It is named for the male's loud call. Others having special names include sicklebills and standardwings.

Among the most notable birds-of-paradise are the plumebirds (plumebird)—the seven species of Paradisaea, 29 to 46 cm (11 ¹/₂ to 18 in.) long. Their central tail feathers are elongated as wires or twisted narrow ribbons, and their filmy flank plumes can be raised and brought forward over the back, hiding the wings. The greater bird-of-paradise (P. apoda) has been introduced into the island of Little Tobago, in Trinidad and Tobago off the coast of Venezuela.

The 12-wired bird-of-paradise (Seleucidis melanoleuca, sometimes S. ignotus) is a short-tailed, 33-cm bird with flank plumes elaborated as forward-curving wires.

The superb bird-of-paradise (Lophorina superba) has a spreading breast shield and a broad cape that turns into a head-fan. The magnificent bird-of-paradise (Diphyllodes magnificus) and Wilson's bird-of-paradise (D. respublica) are caped and have two wirelike tail feathers curving outward; in Wilson's the crown is bare and has a “cross of Christ” pattern. The king bird-of-paradise (Cicinnurus regius), only 13 to 17 cm long, has similar but flag-tipped tailwires and fanlike side plumes.

In the five species of long-tailed birds-of-paradise (Astrapia), males are shining black, sometimes with iridescent ruffs, and have long graduated tails of broad black or black-and-white feathers; total length may be 80 to 115 cm.

The other “paradise” birds are far less colourful. Among them are the sickle-crested, or mocha-breasted, bird-of-paradise (Cnemophilus macgregorii); the wattle-billed, or golden-silky, bird-of-paradise (Loboparadisea sericea); and Loria's, or Lady Macgregor's, bird-of-paradise (Loria loriae)—three species formerly classified as bowerbirds.

Riflebirds are three species of the genus Ptiloris, named perhaps for resemblance of the males' plumage to an early-day British rifleman's uniform. The name has also been attributed to the calls of Queen Victoria's riflebird (P. victoriae) and the paradise riflebird (P. paradiseus)—prolonged hisses, like the passage of bullets through the air.