Serpophaga subcristata

With a compact size, the White-Crested Tyrannulet measures about 4,3 inches and weighs around 0,2 ounces. It has gray-olive upperparts, a white eyebrow, light gray chest, and a pale-yellow belly. When raised, it displays a crest with two bands of white feathers.

It feeds on insects and uses a low perch to launch and catch them in the air, on the ground, or in vegetation. The nest, in the shape of a bowl, is constructed with moss, lichens, Spanish moss, among other materials, and is situated about 3,2 feet above the ground. In territorial disputes, it crouches, flaps its wings, and tail; when facing individuals of the same species, it emits a buzz caused by its wing movement.

It inhabits the upper canopy of the forest, moving almost at the tips of the branches, still concealed by leaves. It can be found on the forest edges at lower heights.

Its most characteristic song consists of one or two spaced high-pitched notes, followed by a sequence of accelerated notes repeated continuously. It can be found from Maranhão, Piauí, and Ceará to Bahia, Minas Gerais, and Rio Grande do Sul, in Brazil.