The grey-sided thrush forages for insects and berries on the ground or less commonly in the trees, often in the company of the eyebrowed thrush (Turdus obscurus). It is also thought to feed on nectar from the flowers of the shingle tree (Acrocarpus fraxinifolius) (3).
The breeding season of the grey-sided thrush is from May to September. The males arrive at the breeding grounds first, establishing territories before the females arrive (4). After mating, the grey-sided thrush collects wet mud and clay from streams to build a bowl-shaped nest, which is normally positioned 1 to 1.5 metres up a small tree surrounded by dense vegetation (3) (4). The female grey-sided thrush generally lays 4 or 5 eggs and both the male and female incubate the eggs until they hatch 14 days later. The new-born chicks will be dependent on their parents for the first 12 to 14 days of life (3).
After the breeding season, the grey-sided thrush begins its lengthy migration southwards, arriving on its wintering grounds in October or November (4).