There are about 60 species of birds in the Pachycephalidae, or whistler and shrike-thrush family. They are found mainly in Australia and New Guinea, as well as parts of South and Southeast Asia, Indonesia, and islands in the southwestern Pacific.

These birds are small to medium-sized, generally measuring about 5–11 inches (12.7–27.9 cm) long. Many have large, rounded heads and strong, thick bills. Their wings and tails vary among species, and some have distinctive crests.

Many pachycephalids are olive, brown, gray, or greenish above and lighter underneath, helping them blend in with their surroundings. However, some species are more brightly colored. They live in many different habitats, including forests, woodlands, shrublands and grasslands.

Most members of this family eat insects and other small invertebrates. They search for food among leaves and branches, in shrubs and sometimes on the ground. Some species also eat fruit.

Many pachycephalids are known for their loud, clear, and sometimes elaborate songs and calls. Their musical voices are one reason many members of the family are called whistlers.