Eurasian Blue Tit

## Description

The Eurasian blue tit is a small passerine bird easily recognizable by its blue and yellow plumage. The bird is famed for its acrobatic skills, as it can cling to the outermost branches and hang upside down when looking for food. A typical Eurasian blue tit has an azure-blue crown and dark blue line passing through the eye, and encircling the white cheeks to the chin, giving the bird a very distinctive appearance. The forehead and a bar on the wing are white. The nape, wings, and tail are blue and the back is yellowish-green. The underparts are mostly sulphur-yellow with a dark line down the abdomen. The bill is black, the legs bluish grey, and the irides dark brown. The sexes are similar, but under ultraviolet light, males have a brighter blue crown. Young blue tits are noticeably more yellow.

## Distribution

Eurasian blue tits are widespread and common resident breeders throughout temperate and subarctic Europe and in parts of the Middle East. They inhabit deciduous or mixed woodlands with a high proportion of oak, shrubland with scattered trees, hedgerows and are common in parks, gardens, and even in the center of towns.

## Behavior

Eurasian blue tits are usually resident and non-migratory birds. They are social and often form mixed winter flocks with Great tits. These small birds are active during the day spending most of their time searching for food in trees, bushes, and sometimes on the ground. Blue tits are very active and agile when foraging; they will often ascend a trunk in short jerky hops, imitating a treecreeper, and can hang from almost anywhere. As a rule, they roost in ivy or evergreens, but in harsh winters will roost wherever there is a suitable small hole, be it in a tree or nesting box. Eurasian blue tits sing and call throughout the year. Songs are mostly used in late winter and spring to defend the territory or to attract mates. Calls are used for multiple reasons. The birds inform one another of their location in trees by means of contact-calls. They use alarm-calls to warn others (including birds of other species) about the presence of predators in the neighborhood. Scolding, for example, is used when a ground predator (e.g. fox, cat, or dog), a low flying predator, or a perched owl are noticed. Sometimes this is followed by mobbing behavior in which birds gather together in flocks to counter a predator. The alarm-whistle warns other birds about the proximity of a Eurasian sparrowhawk, a northern goshawk, a common buzzard, or other flying predators that form a potential danger in the air.

## Diet

Eurasian blue tits are mainly carnivores (insectivores) and prefer insects and spiders in their diet. However, they are also fond of seeds and young buds of various trees, especially when insect prey is scarce.

## Reproduction

Eurasian blue tits are polygynous meaning that males mate with more than one female. The breeding season takes place between April and late June. Courtship includes flights performed by the male and both partners then give series of high-pitched 'zeedling' notes. Eurasian blue tits nest in any suitable hole in a tree, wall, or stump, or an artificial nest box, often competing with house sparrows or great tits for the site. The nest itself is a cup made with dried grasses, moss, leaves, wool, hair, and feathers. The female usually produces 2 broods per year laying 7-14 eggs in each clutch. Incubation lasts about 12 to 16 days and is performed by the female. The male feeds the female during this time. The chicks hatch altricial (helpless) and are fed by both parents. They usually spend 3 weeks in the nest before fledging.

## Population

### Threats

There are no major threats facing Eurasian blue tits at present.

### Number

According to IUCN, the Eurasian blue tit is common and widespread throughout its range but no overall population estimate is available. According to Wikipedia resource there are currently around 20-44 million pairs in Europe. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are increasing.

### Ecological niche

The Eurasian blue tit plays an important role in its ecosystem as the valuable destroyer of pests. It is a well-known predator of many moth species and it also destroys large numbers of coccids and aphids (the worst foes of many plants) than any other bird species.

## Fun Facts

The Blue tit is a very popular European garden bird, due to its perky acrobatic performances when feeding. It can be often seen swinging beneath the holder, calling "tee, tee, tee" or a scolding "churr".

The yellowness of the underparts of Blue tits depends on the number of yellowy-green caterpillars eaten which contain carotene pigments.

Eurasian blue tits are able to open milk bottles with foil tops, to get at the cream underneath. In addition, the instinct to strip bark from trees in search of insects has developed into a tendency to peel building materials such as thatch, wallpaper, stucco and window putty.