Interesting Creatures... The Thrush

Interesting Creatures… The Thrush

Nov 01, 2015 Features / Columnists, Interesting Creatures in Guyana

Thrushes make up the Turdidae, a family of passerine birds that occurs worldwide. These are plump, soft-plumaged, small to medium-sized birds, inhabiting wooded areas, and often feed on the ground. The smallest thrush may be the forest rock thrush, at 21 g (0.74 oz) and 14.5 cm (5.7 in). However, the short wings, which have ambiguous alliances with both thrushes and Old World flycatchers, can be even smaller. The lesser short wing averages 12 cm (4.7 in).

The largest thrush is the blue whistling thrush at 178 g (6.3 oz) and 33 cm (13 in). The great thrush is similar in length, but less heavily built. Most species are grey or brown in colour, often with speckled underparts.

They are insectivorous, but most species also eat worms, land snails, and fruit. Many species are permanently resident in warm climates, while others migrate to higher latitudes during summer, often over considerable distances.

Thrushes build cup-shaped nests, sometimes lining them with mud. They lay two to five speckled eggs, sometimes laying two or more clutches per year. Both parents help in raising the young.

The songs of some species, including members of the genera Catharus, Myadestes, Sialia and “Turdus, are considered to be among the most beautiful in the avian world.

Turdidae species spread the seeds of plants, contributing to the dispersal of many species and the recovery of ecosystems.

Plants have limited seed dispersal mobility away from the parent plant and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time.

Many bats and birds rely heavily on fruits for their diet, including birds in the families: Cotingidae, Columbidae, Trogonidae, Turdidae, and Rhamphastidae. While eating fruit, these animals swallow seeds and then later regurgitate them or pass them in their faeces. Such ornithochory has been a major mechanism of seed dispersal across ocean barriers.

Other seeds may stick to the feet or feathers of birds, and in this way may travel long distances. Seeds of grasses, spores of algae, and the eggs of molluscs and other invertebrates commonly establish in remote areas after long journeys of this sort. The Turdidae have a great ecological importance because some populations migrate long distances and disperse the seeds of endangered plant species at new sites, helping to eliminate inbreeding and increasing the genetic diversity of local flora.

The taxonomic treatment of this large family has varied significantly in recent years. Traditionally, the Turdidae included the small Old World species, like the nightingale and European robin in the subfamily Saxicolinae, but most authorities now place this group in the Old World flycatcher family Muscicapidae.

This article follows the Handbook of the Birds of the World with edits from Clement and Hathaway, Thrushes (2000), and retains the large thrushes in Turdidae. Recent biochemical studies place certain traditional thrush genera (Monticola, Pseudocossyphus, Myiophonus, Brachypteryx, and Alethe) in the Muscicapidae. Conversely, the Asian saxicoline genera Grandala and Cochoa belong here among the thrushes. (Source: Wikipedia – The Free Online Encyclopedia)