The Great Tit (Parus major) is a passerine bird in the tit family Paridae. It is a widespread and common species throughout Europe, the Middle East, Central and Northern Asia, and parts of North Africa in any sort of woodland. It is generally resident, and most Great Tits do not migrate except in extremely harsh winters. Until 2005 this species was lumped with numerous other subspecies. DNA studies have shown these other subspecies to be distinctive from the Great Tit and these have now been separated as two separate species, the Cinereous Tit of southern Asia, and the Japanese Tit of East Asia. The Great Tit remains the most widespread species in the genus Parus.
The Great Tit is a distinctive bird, with a black head and neck, prominent white cheeks, olive upperparts and yellow underparts, with some variation amongst the numerous subspecies. It is predominantly insectivorous in the summer, but will consume a wider range of food items in the winter months, including small hibernating bats. Like all tits it is a cavity nester, usually nesting in a hole in a tree. The female lays around 12 eggs and incubates them alone, although both parents raise the chicks. In most years the pair will raise two broods. The nests may be raided by woodpeckers, squirrels and weasels and infested with fleas, and adults may be hunted by Sparrowhawks. The Great Tit has adapted well to human changes in the environment and is a common and familiar bird in urban parks and gardens. The Great Tit is also an important study species in ornithology.
The Great Tit was originally described under its current binomial name by Linnaeus in his 18th century work, Systema Naturae. Its scientific name is derived from the Latin parus “tit” and maior “larger”.
The 11 subspecies of the Cinereous Tit were once lumped with the Great Tit but recent genetic and bioacoustic studies now separate that group as a distinct species.
The Great Tit was formerly treated as ranging from Britain to Japan and south to the islands of Indonesia, with 36 described subspecies ascribed to four main species groups. The major group had 13 subspecies across Europe, temperate Asia and north Africa, the minor group’s nine subspecies occurred from southeast Russia and Japan into northern southeast Asia and the 11 subspecies in thecinereus group were found from Iran across south Asia to Indonesia. The three bokharensis subspecies were often treated as a separate species, Parus bokharensis, the Turkestan Tit. This form was once thought to form a ring species around the Tibetan Plateau, with gene flow throughout the subspecies, but this theory was abandoned when sequences of mitochondrial DNA were examined, finding that the four groups were distinct (monophyletic) and that the hybridisation zones between the groups were the result of secondary contact after a temporary period of isolation.
A study published in 2005 confirmed that the major group was distinct from the cinereus and minor groups and that along with P.m. bokharensis it diverged from these two groups around 1.5 million years ago. The divergence between the bokharensis and major groups was estimated to have been about half a million years ago. The study also examined hybrids between representatives of the major andminor groups in the Amur Valley where the two meet. Hybrids were rare, suggesting that there were some reproductive barriers between the two groups. The study recommended that the two eastern groups be split out as new species, the Cinereous Tit (Parus cinereus), and the Japanese Tit (Parus minor), but that the Turkestan Tit be lumped in with the Great Tit. This taxonomy has been followed by some authorities, for example the IOC World Bird List. The Handbook of the Birds of the World volume treating the Parus species went for the more traditional classification, treating the Turkestan Tit as a separate species but retaining the Japanese and Cinereous Tits with the Great Tit, a move that has not been without criticism.
The nominate subspecies of the Great Tit is the most widespread, its range stretching from the Iberian Peninsula to the Amur Valley and from Scandinavia to the Middle East. The other subspecies have much more restricted distributions, four being restricted to islands and the remainder of the P. m. major subspecies representing former glacial refuge populations. The dominance of a single, morphologically uniform subspecies over such a large area suggests that the nominate race rapidly recolonised a large area after the last glacial epoch. This hypothesis is supported by genetic studies which suggest a geologically recent genetic bottleneck followed by a rapid population expansion.
The genus Parus once held most of the species of tit in the family Paridae, but morphological and genetic studies led to the splitting of that large genus in 1998. The Great Tit was retained in Parus, which, along with Cyanistes comprise a lineage of tits known as the “non-hoarders”, with reference to the hoarding behaviour of members of the other clade. The genus Parus is still the largest in the family, but may be split again. Other than those species formerly considered to be subspecies, the Great Tit’s closest relatives are the White-naped and Green-backed Tits of southern Asia. Hybrids with tits outside the Parus genus are very rare, but have been recorded with Blue Tit, Coal Tit, and probably Marsh Tit.