The Whistlers (Pachycephalidae), comprise 55 species, part of the ancient Australo-Papuan radiation of songbirds. Its members range from small to medium in size, and occupy most of Australasia. Australia and New Guinea, with species and genera also reaching New Zealand, the South Pacific islands as far as Tonga and Samoa and parts of Asia as far as India.

The whistlers are birds of forests and wooded areas. Most species inhabit rainforest, particularly in the Asian and Papuan parts of their range, but Australian species inhabit a wider range of habitats including woodlands, arid scrubland and mangrove forests. Some species are restricted to a particular ecosystem, whereas others will inhabit a range of habitat types. The whistlers are stout birds with strong bills, and the group was once know as the thickheads due to the large rounded heads of many species. Their plumage is rufous, brown, or grey in the majority of species. Nevertheless a few species, have bright plumage. They are insectivorous, picking insects off leaves, branches, or leaf litter. While insects make up the majority of the diet they will also feed on spiders, worms, centipedes, snails, and small crabs; larger species will also tackle small vertebrates such as frogs, geckos and baby birds. They are generally sedate foragers and do not engage in hawking to obtain prey, instead being gleaners and probers.

Several species belonging to this family are outstanding songsters: the whistlers produce an astonishing volume for their size, and the lyrebirds aside, the Grey Shrike-thrush is often regarded as the finest, most inventive songbird of them all.