PICIFORM

order of birds (Piciformes) consisting of six families of arboreal birds: the familiar woodpeckers, their relatives the piculets and wrynecks (collectively, the family Picidae), and the exotic tropical jacamars (Galbulidae), puffbirds (Bucconidae), barbets (Capitonidae), honey guides (Indicatoridae), and toucans (Ramphastidae). Piciforms vary in size from 3.5 inches (9 centimetres) to 24 inches. Characteristic of this order is the zygodactyl foot, where two toes point forward and two backward. The structure of the bill varies greatly throughout the Piciformes. That of some species of woodpeckers is chisel-like and broadly based, with slitlike nostrils to keep wood chips out. The huge, serrated bill of the toucans is supported by a crisscrossing of many bony fibres; it is strong but surprisingly lightweight for its size. Downy woodpecker (Dendrocopos pubescens). The medium-sized jacamars have long, slender bills and resemble hummingbirds in their body shape and their bright, iridescent plumage. The puffbirds are similar to the jacamars, although with shorter tails and bills. Their plumage is relatively subdued, usually brown, tan, or mottled. Large heads and stout bills on thick bodies typify the barbets, in addition to bristles at the base of the beak. The barbets include some of the most beautifully coloured of birds; many of these are bright green with red, orange, and yellow highlights. Honey guides have thick skins which protect them against bee stings. These birds are small and the plumage is generally drab. Coloration of the toucan is quite vividtoucans are black or green with various patterns of bright hues on the underparts and the laterally flattened bill. The woodpeckers are well adapted to their life-style. Strong leg muscles and toes enable them to cling to vertical surfaces, and the central tail feathers are stiffened and help to support the birds while they are foraging on tree trunks (see photograph). The woodpecker's tongue has tiny barbs and can be extruded at high speeds to take insects found in holes in the bark. There is a great diversity of habits within the piciforms. Jacamars and puffbirds are the flycatchers of the order; both tend to go after their prey from a perch. Jacamars are more forest-oriented while puffbirds inhabit more open areas. When jacamars capture large insects, they take them back to the perch and beat them against it before eating them, pulling the wings off the prey if it is to be given to nestlings. Barbets are usually inhabitants of savannas and woodlands. They feed upon insects, fruits, berries, and buds. The honey guides also dwell in forests or savannas, where they subsist mainly on insects, beeswax, and fruit. This wax-eating habit is unique among birds; honey guides have special intestinal bacteria which help break down this substance. A few species in the genus Indicator actually lead man or other mammals to bees' nests. The greater, or black-throated, honey guide (I. indicator) raises and spreads its tail and weaves about in flight. When this attracts attention, it flies to a perch and calls again; then it repeats the display, slowly moving toward the bees' nest where it feasts on wax and exposed larvae after the guided mammal has torn open the nest and taken the honey. The toucans are well known as fruit eaters; they pick up small pieces of fruit in the bill and then throw them back into the mouth. Their diet, however, also includes insects, eggs, and even baby birds. Toucans usually reside in the forest but they may forage in clearings or around farms. Among the woodpeckers, the soft-tailed wrynecks (Jynx) forage for ants in both terrestrial and arboreal situations, and the piculets tap and probe for insects in a woodpecker-like manner as they travel along vines and small branches. Most woodpeckers (Picinae) take insects from the surface of the tree or crevices within the bark. Only a few of the heaviest-billed birds actually drill into the tree while foraging. All the piciforms are hole nesters. Woodpeckers drill nesting cavities into living or dead trees. Their two to nine white eggs require an incubation period of 11 to 20 days. The adults share in the incubation of the eggs and in feeding the nestlings. Both jacamars and puffbirds usually nest at the end of tunnels dug into the ground, although some puffbirds nest in trees. Again, both male and female are involved in parenting. Barbets excavate their nests in dead trees with well-rotted heartwood. Two to five eggs are incubated from 13 to 15 days. The toucans usually take over an old woodpecker hole, which they may enlarge slightly. The parents take turns incubating the one to four eggs for about 16 days. The young of the larger toucan species may remain in the nest for seven weeks or longer and then may remain with the parents for an extended period. Reproduction in the honey guides is unlike that of the other piciforms; they are brood parasites. The female honey guide lays one white egg within the nest of a hole-nesting host species; she breaks any other eggs in the nest at that time. When the young honey guide hatches it has a sharply hooked tip on its beak with which it kills off any other nestlings which have hatched. Black-throated honey guides frequently parasitize the red-throated bee-eater (Merops bulocki); the food call of the young honey guide sounds like the calls of two hatchling bee-eatersthis keeps the foster parents highly stimulated to provide food for their parasite. (order Piciformes), any member of the group of birds that includes the familiar woodpeckers, their relatives the piculets and wrynecks (collectively, the family Picidae), and the exotic tropical jacamars (Galbulidae), puffbirds (Bucconidae), barbets (Capitonidae), honey guides (Indicatoridae), and toucans (Ramphastidae). This arboreal group of about 370 species is distributed on all continents except Australia and Antarctica, but only the woodpecker family is widespread outside the tropics. Although the six families comprise the order, over half of the species represent one subfamily (Picinae, true woodpeckers) of the family Picidae. Downy woodpecker (Dendrocopos pubescens). The order includes such familiar birds as the European great spotted woodpecker (Dendrocopos major) and green woodpecker (Picus viridis) and the American flicker (Colaptes auratus) and downy woodpecker (Dendrocopos pubescens; see photograph). Piciforms are economically important because they include many insect-eating species. A few species are harmful in eating fruit (toucans) or damaging trees (sapsuckers, genus Sphyrapicus), but even these species eat some insects and other animals, and they of course serve as natural balances within the ecological systems of which they are a part. The tropical distribution of most piciform families suggests that these represent specialized remnants of a once more numerous and diverse array of arboreal birds. Perhaps many elements of the order became extinct during the geologically recent burgeoning of the diverse, ubiquitous, and highly successful order Passeriformes, which the piciforms resemble in many ways. It has even been suggested that both groups be merged into one order. Piciform species vary in size from about nine to more than 60 centimetres (3 1/2 to 24 inches) in overall length. They vary greatly in the structure of their beaks and only slightly less in the rest of their morphology, some, such as the huge-billed toucans and the sturdy woodpeckers, being very specialized. The specialized habits of the wax-eating honey guides are unique among birds. The most numerous and widely distributed groups, the barbets (70 species) and the woodpeckers (about 203 species), excavate their own nesting cavities, thereby avoiding competition with other birds and, incidentally, providing homes for many other species of vertebrates. Additional reading Herbert Friedmann, The Honey-Guides (1955), is a technical but readable account of the habits and relationships of honey guides. J. Van Tyne, The Life History of the Toucan, Ramphastos brevicarinatus (1929), provides a good, though technical, account of the habits of a large toucan. Journal articles on various species include Alexander F. Skutch, Life-History of the Blackchinned Jacamar, Auk, 54:135146 (1937), the only relatively complete study of a species of jacamar, Life History Notes on Puff-Birds, Wilson Bulletin, 60:8197 (1948), which, though not complete on any species, contains most of the information known about the habits of puffbirds, Life History of the Blue-Throated Toucanet, Wilson Bulletin, 56:133151 (1944), a very readable study of another small toucan, The Life-History of the Prong-Billed Barbet, Auk, 61:6188 (1944), a reasonably complete account of the habits of a barbet, one of few extant detailed accounts, and Life History of the Olivaceous Piculet and Related Forms, Ibis, 90:433449 (1948), an interesting account of the habits of these little relatives of the woodpeckers; H.O. Wagner, Notes on the Life History of the Emerald Toucanet, Wilson Bulletin, 56:6576 (1944), a general account of the habits of a small toucan; and S.D. Ripley, The Barbets, Auk, 62:542563 (1945), chiefly a taxonomic, technical treatment, but it summarizes the habits and characteristics of various groups. Dieter Blume, ber die Lebensweise einiger Spechtarten (Dendrocopos major, Picus viridis, Dryocopus martius) (1961), is the classic modern behavioral treatment of woodpeckers, covering three common European species (fairly technical). Heinz Sielmann, My Year with the Woodpeckers, trans. from German (1959), is a readable, accurate account of the habits of European woodpeckers. Louise de Kiriline Lawrence, A Comparative Life-History Study of Four Species of Woodpeckers (1967), presents an accurate though not overly technical treatment of the habits of some North American species. James T. Tanner, The Ivory-Billed Woodpecker (1942, reprinted 1966), delineates the habits and history of one of the largest woodpeckers, now nearly extinct on the North American continent. Lester L. Short, Woodpeckers of the World (1982), provides extensive coverage. Lester L. Short The Editors of the Encyclopdia Britannica