The Wren is one of the smallest birds in Europe, weighing no more than 5–6 grams. It has olive-green plumage with a distinctive yellow stripe on the top of its head, edged in black. This small bird feeds mainly on insects and spiders, which it actively hunts among the leaves of trees. Its song is a thin, high-pitched trill, often difficult to hear. It prefers coniferous forests. Breeding occurs between April and June, during which it builds a cup-shaped nest suspended among the branches.