• The black redstart hunts prey up to 7 cm in size. Sometimes it catches caterpillars and earthworms up to 7 cm long, then tears them into pieces.

The black redstart primarily feeds on insects and other small invertebrates, catching them on the ground, rocks, and in the air during summer; the species supplements its diet with berries in autumn and winter. The common redstart obtains food through surface foraging and catching prey in short flights, consuming insects, spiders, small worms, berries, tiny worms, and insect larvae. Its hunting strategy involves active searching and acquisition of food, with a daily food requirement ranging from 6 grams to 12 grams. The diet includes beetles, flies, Hymenoptera, butterflies, bedbugs, Orthoptera, dragonflies, mayflies, and lacewings.