The bushtits or long-tailed tits, are a family, Aegithalidae, of small, drab passerine birds with moderately long tails. The family contains 13 species in three genera, all but one of which are found in Eurasia. Bushtits are active birds, moving almost constantly while they forage for insects in shrubs and trees. During non-breeding season, birds live in flocks of up to 50 individuals. Several bushtit species display cooperative breeding behavior, also called helpers at the nest.
All the Aegithalidae are forest birds, particularly forest edge and understory habitats. The species in the genus Aegithalos prefer deciduous or mixed deciduous forests, while the Indonesian pygmy bushtit is found mostly in montane coniferous forest. Bushtits are found in a wide range of habitats, including on occasion sagebrush steppe and other arid shrublands, but are most common in mixed woodland. Most species in this family live in mountainous habitats in and around the Himalayas, and all are found in Eurasia except the American bushtit, which is native to western North America. The long-tailed tit has the most widespread distribution of any species of Aegithalidae, occurring across Eurasia from Britain to Japan. Two species, in contrast, have tiny distributions, the Burmese bushtit, which is entirely restricted to two mountains in Burma, and the pygmy bushtit, which is restricted to the mountains of western Java. The species in this family are generally not migratory, although the long-tailed tit is prone to dispersing in the northern edges of its range (particularly in Siberia). Many mountainous species move to lower ground during the winter.