Photo Of The Woodpecker
The woodpeckers, piculets and wrynecks are a family, Picidae, of near-passerine birds. Members of this family are found worldwide, except for Australia and New Zealand, Madagascar, and the extreme polar regions. Most species live in forests or woodland habitats, although a few species are known to live in treeless areas such as rocky hillsides and deserts.
Photo Of The Woodpecker
The Picidae are just one of the eight living families in the order Piciformes. Members of the order Piciformes, such as the jacamars, puffbirds, barbets, toucans and honeyguides, have traditionally been thought to be very closely related to the woodpeckers, piculets and wrynecks. More recently, DNA sequence analyses have confirmed this view.
Photo Of The Woodpecker
There are about 200 species and about 30 genera in this family. Many species are threatened or endangered due to loss of habitat or habitat fragmentation. Two species of woodpeckers, the Ivory-billed Woodpecker and the Imperial Woodpecker, have been considered extinct for about 30 years (there has been some controversy recently whether these species still exist).
Description Of The woodpeckers
The smallest woodpecker is the Bar-breasted Piculet, at 7 g and 8 cm (3 1/4 inches). The largest woodpecker was the Imperial Woodpecker, at an average of 58 cm (23 inches) and probably over 600 g (1.3 lb). The Ivory-billed Woodpecker is (or was) slightly smaller at 50 cm (20 inches) and a weight of 500 g (1.1 lb). If both the Ivory-billed and Imperial Woodpeckers are indeed extinct, the largest extant woodpecker is the Great Slaty Woodpecker of Southeast Asia, at about 50 cm (20 inches) and 450 g (1 lb). A number of species exhibit sexual dimorphism in size, bill length and weight. In the piculets it is often the females that are larger, amongst the woodpeckers that show sexual dimorphism it is usually the males that are larger.
Most species possess predominantly white, black and brown, green and red plumage, although many piculets show a certain amount of grey and olive green. In woodpeckers, many species exhibit patches of red and yellow on their heads and bellies, and these bright areas are important in signalling. The dark areas of plumage are often iridescent. Although the sexes of Picidae species tend to look alike, many woodpecker species have more prominent red or yellow head markings in males than in females.
Members of the family Picidae have strong bills for drilling and drumming on trees and long sticky tongues for extracting food. Woodpecker bills are typically longer, sharper and stronger than the bills of piculets and wrynecks; however their morphology is very similar. The bill's chisel-like tip is kept sharp by the pecking action in birds that regularly use it on wood. Species of woodpecker and flicker that use their bills in soil or for probing as opposed to regular hammering tend to have longer and more decurved bills. Due to their smaller bill size, many piculets and wrynecks will forage in decaying wood more often than woodpeckers. The long sticky tongues, which possess bristles, aid these birds in grabbing and extracting insects deep within a hole of a tree. It had been reported that the tongue was used to spear grubs, but more detailed studies published in 2004 have shown that the tongue instead wraps around the prey before being pulled out.
Photo Of The Woodpecker
Many of the foraging, breeding and signaling behaviors of woodpeckers involve drumming and hammering using the bill. To prevent brain damage from the rapid and repeated decelerations, woodpeckers have evolved a number of adaptations to protect the brain. These include small brain size, the orientation of the brain within the skull (which maximises the area of contact between the brain and the skull) and the short duration of contact. The millisecond before contact with wood a thickened nictitans membrane closes, protecting the eye from flying debris. The nostrils are also protected; they are often slit-like and have special feathers to cover them.
Photo Of The Woodpecker
Breeding Of The woodpeckers
All members of the family Picidae nest in cavities. Almost every species nests in tree cavities, although in deserts some species nest inside holes in cactus and a few species nest in holes dug into the earth. Woodpeckers and piculets will excavate their own nests, but wrynecks will not. The excavated nest is usually only lined from the wood chips produced as the hole was made. Many species of woodpeckers excavate one hole per breeding season, sometimes after multiple attempts. It takes around a month to finish the job. Abandoned holes are used by other birds and mammals that are secondary cavity nesters. Because nesting holes are in great demand by other cavity nesters, woodpeckers face competition for the nesting sites they excavate from the moment the hole becomes usable. This may come from other species of woodpecker, or other cavity nesting birds like swallows and starlings. Woodpeckers may aggressively harass potential competitors, and also use other strategies to reduce the chance of being usurped from their nesting site; for example the Red-crowned Woodpecker digs its nest in the underside of a small branch, which reduces the chance that a larger species will take it over and expand it.
Members of Picidae are typically monogamous, with a few species breeding cooperatively and some polygamy reported in a few species. Polyandry, where a female raises two broods with two separate males, has also been reported in the West Indian Woodpecker. A pair will work together to help build the nest, incubate the eggs and raise their altricial young. However, in most species the male does most of the nest excavation and takes the night shift while incubating the eggs. A nest will usually consist of 2-5 round white eggs. Since these birds are cavity nesters, their eggs do not need to be camouflaged and the white color helps the parents to see them in dim light. The eggs are incubated for about 11–14 days before the chicks are born. It takes about 18–30 days before the young are ready to leave the nest.