Woodpeckers and Relatives: Piciformes
WOODPECKERS AND RELATIVES: Piciformes
Woodpeckers and their relatives make up the order Piciformes, which includes six families of birds that nest in cavities (hollow areas within a rock or tree): jacamars (Galbulidae); puffbirds (Bucconidae); barbets (Capitonidae); honeyguides (Indicatoridae); woodpeckers, wrynecks, and piculets, (Picidae); and toucans (Ramphastidae).
Although the six families look very different, most piciform birds share a common adaptation that helps them live in trees. This special feature is zygodactylous (zye-guh-DACK-tuhl-us; "yoke-toed" or "X-shaped") feet, which have two toes in front and two toes behind. With this arrangement, the birds can easily grab onto bark while hopping along branches and running up and down tree trunks. Along with this special feature, woodpeckers and their relatives also have similar jaw muscles and tongues, and do not have down feathers (except the jacamars). The tongue is capable of sticking out of its bill up to 4 inches (10 centimeters) in the green woodpecker, allowing it to take insects from deep cracks and crevices.
Piciforms are small- to medium-sized birds. They also share similar skeletal features, especially with the bones of the vertebrae (spinal column), sternum (breastbone), and ribs. Many members have heavy, sturdy bills, but the general size and shape of the bills varies widely. Jacamars have longish pointed bills; puffbirds have large, broad, often hooked bills; barbets have largish, generally heavy, sometimes notched bills; woodpeckers have strong, tapering, often chisel-tipped bills; honeyguides have relatively short bills that can be either stubby or pointed; and toucans have huge, colorful bills. The colorful plumage (feathers) found on most of the birds is very different among all of the piciform birds. However, they almost always contain combinations of black and white with accents of red and yellow.
Males and females usually look alike, but with some small differences in the color of nape (back part of neck) patches and the presence or absence of feathers around the bill, or what is called their "moustaches." One exception is Neotropical barbets, which show a great difference between males and females with regard to plumage color and pattern. Woodpeckers (one of three groups in the family Picidae) are unique within the family, order, and, in fact, among all birds in that they have strong, extra-stiff tail feathers that are used to brace themselves against tree trunks while climbing vertically or hammering with their beaks. Barbets also use their tail as a brace, but only while digging nest cavities. Woodpeckers and relatives are 3 to 22 inches (8 to 56 grams) long and weigh between 0.3 and 20 ounces (8 and 569 grams).
Even though they do not migrate, piciform birds make up one of the most widespread bird orders, mostly due to the woodpeckers that are found on all the world's continents except for Antarctica and Australia. The other piciform families are less widely distributed; the jacamars, toucans, and puffbirds are only found in the New World tropics, and honeyguides only found in Southeast Asia and Africa. Barbets are found in both the tropics of the New World and the Old World.
Piciforms inhabit forests and woodlands, mostly in tropical environments. They are arboreal—that is, they live in trees. Many of the species prefer mature forests with a closed canopy, meaning the tallest trees' leaves let little light onto the forest floor. However, some species prefer open, fragmented forests and woodland savannas (flat grasslands) while other species like forest edges, stream banks, grasslands, orchards, and parks.
Woodpeckers and their relatives eat a variety of foods and therefore, have a big difference in bill structure. Woodpeckers, jacamars, honeyguides, and puffbirds eat mostly insects and their larvae (LAR-vee; active immature insects), but some woodpeckers also eat fruit and nuts. Honeyguides also eat beeswax from beehives. Toucans and barbets eat mainly fruits, but do feed insects and other similar foods to young. Jacamars and puffbirds locate prey while in the air, eating mostly butterflies (for jacamars) and flying beetles (for puffbirds). Woodpeckers and their relatives also catch their prey with different techniques: taking them from leaves, branches, and tree trunks; probing into bark crevices and removing bark; drilling holes to insert tongues; carving off large pieces of bark; pecking funnel-shaped holes into ants' nests; or catching prey in flight. Their sturdy, stout beaks allow them to find prey in wood and other similar materials.
BEHAVIOR AND REPRODUCTION
Woodpeckers and relatives are not considered very social birds, except for a few species. They are rarely seen on the ground or flying in the air, but are mostly found searching for food, eating captured prey, nesting, raising young, and roosting in trees. Most piciform birds do not migrate, move seasonally, but remain in their home range throughout the year. However, a few species migrate many miles between their breeding and wintering areas. A male-female pair will breed alone, but will maintain their bond—especially for woodpeckers, puffbirds, and barbets—throughout the year as they protect their territory. Some species of toucans form small flocks while foraging for food, and honeyguides and barbets come together at times when there is plenty of food available.
Piciforms are good climbers but weak flyers, except for honeyguides who are strong, acrobatic birds. Woodpeckers and relatives communicate in many different ways. They ruffle their crown feathers, spread their wings, sway the head, hop and dance about, and tap and drum their bill on tree trunks and branches.
Piciforms have two unique and very unusual behaviors that are unknown anywhere else in the bird community. First, woodpeckers and a few species of barbets communicate to one another by "drumming" (that is, tapping or hammering) rhythmically on hollow trees or other such structures in particular ways (depending on the species). Second, honeyguides, as their name says, "guide" animals such as honey badgers, baboons, and humans to bees' nests with the use of calls and short flights to the nests. When one of these animals is drawn to a beehive and breaks it open, the honeyguides help themselves to the beeswax.
Woodpeckers and their relatives are territorial, living in individual, pair, or family territories. They often defend a territory even from their own species. They display several courtship activities; among them, drumming and tapping on trees in specific patterns, flights into the air, and expressive calls to attract a mate. In fact, the black woodpecker taps about forty-three times within a two and a half-second period. They nest (and roost) in cavities, with some families laying their eggs in the nests of other hole-nesting species such as woodpeckers and barbets. The type of cavity used varies among the six families. Some species of jacamars and puffbirds dig out decayed trees among former termite nests, while other species dig burrows in soil, often along riverbanks. Barbets and woodpeckers use their strong, sharp beaks to hammer out nest cavities in rotting trees. Other birds often take over such nests, making woodpeckers and their relatives helpful to such birds. The large species of toucans use natural holes in trees, while the smaller species often drive out woodpeckers from newly dug holes, and then enlarge the holes to suit their needs. They will reuse the nests for many years.
Almost all woodpeckers and their relatives lay white eggs. During the incubation period, the mating pair will nest at intervals of thirty to 150 minutes. The nestling period is eighteen to thirty-five days. The whole family breaks up from one to eight weeks after the young leaves the nest.
DRUMS OF WOODPECKERS
All woodpeckers tap or "drum" their bills rapidly against wood in order to defend their territory and to attract mates. This drumming is used instead of songs in most species. The length, speed, frequency, and loudness at which a particular woodpecker drums often identify a particular species. However, the quality of the drumming sound often depends on the type of wood on which the woodpecker is tapping.
WOODPECKERS, RELATIVES AND PEOPLE
People have historically used feathers from toucans and woodpeckers for ceremonial ornaments. Humans hunt many of the larger species for food. Woodpeckers and relatives play an important role in the forest ecosystem, helping to control insects and the cycle of decay and regrowth of plants and animals. The blue toucan is well known in some countries as the mascot for a popular breakfast cereal, while Woody the Woodpecker has been a popular cartoon character for many decades.
Many homeowners, however, consider woodpeckers as pests because of the damage done to homes and other building structures by the use of their bills. For the most part, scientists regard piciform birds as beneficial to the environment. Toucans and barbets greatly help to scatter seeds. Woodpeckers help to control pest insects in forests, while holes pecked out in trees help other birds and some animals such as squirrels in finding nest locations.
According to recent research, fifteen species (of a total of 383 species) of piciform birds are classified as Critically Endangered, Endangered, or Vulnerable, at an extremely high, very high, or high risk of extinction. Another twenty-eight species are classified as Near Threatened. Experts on the birds warn that even though fewer than 4 percent of the birds are threatened, continued loss of habitat greatly harms the ability of the birds to reproduce and live. Decreased numbers of piciformes have also occurred due to hunting and capture for pets and other human activities. In fact, collecting of some species for museums is believed to have contributed to the extinction of some of those species.
FOR MORE INFORMATION
Baughman, Mel M., ed. Reference Atlas to the Birds of North America. Washington, DC: National Geographic, 2003.
del Hoyo, J., A. Elliott, J. Sargatal, J. Cabot, et al., eds. Handbook of the Birds of the World. Barcelona: Lynx Edicions, 1992.
Dickinson, Edward C., ed. The Howard and Moore Complete Checklist of the Birds of the World, 3rd ed. Princeton, NJ and Oxford, U.K.: Princeton University Press, 2003.
Field Guide to the Birds of North America, 4th ed. Washington, DC: National Geographic Society, 2002.
Forshaw, Joseph, ed. Encyclopedia of Birds, 2nd ed. San Diego, CA: Academic Press, 1998.
Harrison, Colin James Oliver. Birds of the World. London and New York: Dorling Kindersley, 1993.
Kaufman, Kenn, et al. Birds of North America. New York: Houghton Mifflin, 2000.
Sibley, David. The Sibley Guide to Birds. New York: Alfred A. Knopf, 2000.