The Caspian Tit is a passerine

Passerine

A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...

 bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 in the tit family. It is often lumped with Sombre Tit

Sombre Tit

The Sombre Tit is a member of the tit family found in southeast Europe and southwest Asia.Though it is traditionally placed in Parus, mtDNA cytochrome b sequence data suggests that that genus should be split, as already adopted by the American Ornithologists' Union, for example...

 Poecile lugubris (del Hoyo et al. 2007), but some research suggests that it is a separate species, more closely related to Willow

Willow Tit

The Willow Tit is a passerine bird in the tit family Paridae. It is a widespread and common resident breeder throughout temperate and subarctic Europe and northern Asia. It is more of a conifer specialist than the closely related Marsh Tit, which explains it breeding much further north...

 and Songar Tit

Songar Tit

The Songar Tit is a passerine bird in the tit family. It is the southern counterpart of the Willow Tit P...

s (Harrap & Quinn 1996).

It breeds in the deciduous mountain forests of northern Iran

Iran

Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

, just extending into Azerbaijan

Azerbaijan

Azerbaijan , officially the Republic of Azerbaijan is the largest country in the Caucasus region of Eurasia. Located at the crossroads of Western Asia and Eastern Europe, it is bounded by the Caspian Sea to the east, Russia to the north, Georgia to the northwest, Armenia to the west, and Iran to...

.

The 12.5 cm long Caspian Tit has a dark brown cap and bib, rich brown upperparts and underparts which are pinkish-buff when fresh, but become paler and greyer as the feathers age. The sexes are similar, but juveniles are somewhat duller.

The most common call of this generally quiet bird is a thin zsit, but a nasal double note, chev chev, is also given.

The Caspian Tit excavates its own nesting hole, usually in a rotten stump or in a tree, more or less decayed. Most nests examined are cups of felted material, such as fur, hair and wood chips, but feather

Feather

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...

s are sometimes used. The number of eggs varies from five to seven, white with faint reddish spots or blotches.

It feeds on caterpillar

Caterpillar

Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...

s, insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s and seeds, much like other tits.