22 July 2011
Since the song thrush has two or three broods a year, the breeding season is long and lasts from March to August.
The onset of breeding is determined by the weather, which can bring it forward or delay it by several days.
The nest, built entirely by the female, is low down in any suitable cover, including trees and shrubs, among creepers on walls, on ledges, and on the ground amongst thick vegetation. It is a neat structure of twigs, grass and moss, cemented together and thickly lined with mud, dung and rotten wood, often mixed with leaves. It can take three weeks to complete. Sometimes the same nest is used for successive broods.
Normal clutch size is 3-5, with one egg laid each day. The female starts to incubate once the last egg is laid, and the chicks hatch 13-15 days later. Only the female broods the chicks, but both parents feed them. The chicks are fed primarily on worms, but slugs, caterpillars, and even fruit can feature in the diet, especially when dry weather limits access to worms.
The chicks are ready to fledge at 13-14 days, but if the nest is disturbed, they can leave as early as nine days old. They creep and flutter from the nest, and remain in nearby cover for a few days.
They are more or less flightless at first, but within a week can fly well. They continue to be fed by the parents while they are learning to find and handle food themselves. The young birds will be independent about three weeks after leaving the nest.
Fledged young are often left in the care of the male, while the female prepares for the next nesting effort. Nestlings from later broods can be found until August. There are considerable losses at egg and chick stage, with only a third of nests producing fledged young.