|Know your wildlife - By Violah Makuvaza|
|Saturday, 21 July 2012 20:44|
Ndebele name: Isinqolamthi, Shona name: HohodzaTHE name is derived from the habit of climbing on trees and drilling into the bark for insect prey, a feeding method which attains its greatest development in this family. Out of nine species of southern African woodpeckers, four are found throughout Zimbabwe. These are the Bennett’s Woodpecker, Goldentailed Woodpecker, Cardinal Woodpecker and the Bearded Woodpecker. The Little Spotted Woodpecker is confined to eastern Zimbabwe, the Olive Woodpecker is scarcely found in Victoria Falls and the others are not found in Zimbabwe.
The woodpeckers’ plumage is variable and they are clearly marked on the belly, streaked bellies in the Goldentailed and Cardinal Woodpeckers, spotted belly in Bennett’s Woodpecker and barred belly in Bearded Woodpecker. The plumage is different for the sexes. The neck of the woodpecker is slender but very strong because of its exceedingly powerful muscles.
The wings are strong, rather rounded and the tail is rounded or wedge-shaped with the tail feathers modified forming the spine-tipped stiff rectrices which practically facilitate clinging to vertical surfaces.
The central pairs of retrices are shed in the moult after the others have regrown, an adaptation to preserve the supporting function of the tail. Woodpeckers have strong chisel-like beaks for drilling into wood for food or for nest construction and have thickened, shock absorbent bones of the head and strong neck muscles to make such poundings feasible.
The nostrils are covered by bristle-like feathers that protect the nostrils from wood dust. The tongue is extraordinarily long by means of muscles extending posteriorly around the back of the skull and originating at the base of the right upper jaw cavity and behind the right orbit allowing the tongue to be protruded about the length of the bill or more.
The tongue is cylindrical in cross section making it worm-like and mobile, it is capable of an extreme degree of protrusion owing to the great length of the supporting bones (horns). The tip of the tongue is hard and more or less bordered with bristles or borbs. It is coated with mucous from the well developed glands at its base making it sticky and used as an organ of touch and taste.
Climbing and Feeding
The hunt for food is usually over a restricted territory, which is scoured daily. The food consists of insects, fruits, nuts and the sap of trees. Sometimes this diet changes seasonally or the food is partly stored. The entire surface of each tree is examined from top to bottom. The flight from tree to tree is both jerky and noisy. On the ground the bird has an ungainly way of hopping after insects and worms. It attacks only wood-eating insects. Its stomach is always crammed with the pests of cultivated lands and forests. Woodpeckers are essentially tree-climbing birds clinging to a tree trunk with their claws using the stiff, spiky tail feathers as additional support. In this position using the robust head they hammer away at the bark with their strong wedge-shaped bill to extract insect larvae. The prey is then probed from the crevices with the tongue. The tongue can be used as a lime-twig for catching ants, as a brush for licking the sap of trees or as a lance to spear larger insects. Woodpeckers drill with their powerful beaks for borers that infest trees.
Almost all woodpeckers have a loud and harsh voice, some have laughing or ringing cries. Many species produce an instrumental drumming sound by very rapid blows with the bill on dead branches. Birds which do not sing substitute other performances. The woodpeckers drum on dead limbs, and have strengthened neck muscles and thickened skull bones to withstand the pounding. The loud drumming of flickers on wood about dwellings can be an annoyance.
Breeding and Nesting
Woodpeckers excavate holes in dead trees, stumps or branches and lay their eggs in the cavity, on the bare floor of the excavation. They lay 2-8, pure white eggs. Woodpeckers nestlings often seem reluctant to venture out of a tree cavity and their first flight may end disastrously, in the clutches of a waiting predator, a tangle of briars, or a puddle of water. The nestling is fed by both parents and leaves nest after about 27 days which is fairly long a period. Woodpeckers sometimes construct new winter quarters seperate from their nesting holes, the male and female living apart.
Woodpeckers are usually solitary or in pairs when breeding. Woodpeckers sometimes do damage to trees or buildings in their quest for woodborers or for drumming sites. They tend to roost at low elevations on winter nights, where it is often more sheltered and warmer due to radiation.
* Violah Makuvaza is an Ornithology Curator at the Natural History Museum of Zimbabwe