Habitat

Most thrushes are forest birds. Rock thrushes (Monticola) are least tied to woodland, although some are very much woodland birds in their wintering areas, even though they breed in open places. In some species, part of the population may be relatively tame and confiding and live close to human settlements, while others remain shy.

Each species has a preferred habitat that may be extremely narrow or very broad. The American robin has been called one of the most adaptable of North American birds as it has such a wide habitat choice: it lives in just about any kind of forest, in parks, gardens, and farmland, showing a similar ability to accept a wide variety of habitat in winter and in summer. The eastern bluebird (Sialia sialis) is found in open woodland, orchards, gardens, and farmland, whereas the western bluebird (S. mexicana) prefers high-altitude slopes and recently burned areas. Many similar pairs or groups of species are separated by such differences in habitat choice.

An example of a rather narrow habitat requirement is the dense thicket needed by the nightingale (Luscinia megarhyn-chos) in Europe. Conservationists repeatedly cut trees down to the stump to encourage the growth of new, slender poles from ground level; a dense canopy is of no use for the nightingale,

A mountain bluebird (Sialia currucoides) fluffs its feathers to keep warm in cold weather. (Photo by R. Curtis/VIREO. Reproduced by permission.)

which requires thick growth right down to the ground, where it feeds and nests. Changes in forest management over the years threatened nightingales until wardens of nature reserves started to replicate out-dated forest practices.

The bluethroat (L. svecica) has much closer affinity to the edges of wetlands, where it skulks in reeds and dense willow thickets. The redstart (Phoenicurus phoenicurus) is principally a bird of oak woodland with a thick, dense canopy above an open forest floor, but it also enjoys the light of woodland glades and forest edge. An all-year resident in Europe is the black redstart (P. ochruros), a bird of cliffs and crags that drops down in winter to rocky shores and the floors of quarries. It has increased and expanded its range by occupying many European towns and villages, finding holes under tiles and in old stonewalls that make an ideal alternative to a hole in a cliff for nesting. It showed a particularly interesting expansion of range into southern England after World War II, when it moved into the vast areas of rubble and crumbling brickwork left by bombing raids on London and elsewhere. With the clearance of such sites from English cities, the black redstart has found it difficult to survive as a British breeding bird, although some still spend the winter in semi-derelict places near the coast where concrete and building rubble replicate a rocky habitat. The blackstart (Cercomela melanura) from the Middle East, another species with a narrow habitat, is a desert rock specialist, living in wadis and along the foot of crags with hot, bare rock and nothing more than a few scrubby acacia bushes. In parts of Africa, the mocking chat (Thamnolaea cinnamomeiventris) lives on exposed rocky outcrops on otherwise wooded cliffs. It finds that tourist lodges around places such as Lake Nakuru in Kenya are useful alternative sites, with stone-walled rooms with tiled roofs mimicking the rock outcrops quite well.

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