# Blue Tit — Facts, Threats & Conservation

*Cyanistes caeruleus*

> A blue tit (Cyanistes caeruleus) is a small European songbird with a blue cap and wings, white cheeks and a yellow breast. Weighing about 11 grams, it is a common, acrobatic garden-feeder visitor across Britain, Ireland and much of Europe, and an IUCN Least Concern species.

**IUCN status:** Least Concern (IUCN)  ·  **WARN range:** United Kingdom and Ireland, Mainland Europe, Western Asia, North-west Africa, Middle East

## Quick facts
| Fact | Value |
| --- | --- |
| Common name | Eurasian blue tit |
| Scientific name | Cyanistes caeruleus |
| Family | Paridae (tits and chickadees) |
| Body length | 10.5-12 cm |
| Wingspan | 17.5-20 cm |
| Weight | About 11 g |
| Diet | Insects, spiders, seeds, nuts and fruit |
| Typical clutch | Around 8 eggs, sometimes a dozen or more |
| Lifespan | Usually a few years; up to 10+ years recorded |
| IUCN status | Least Concern |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Aves
- **Order:** Passeriformes
- **Family:** Paridae
- **Genus:** Cyanistes
- **Species:** Cyanistes caeruleus

## Conservation status
- **Status:** Least Concern. The Eurasian blue tit is assessed as Least Concern on the IUCN Red List. It has a very large range and a large population, and is one of the most common and widespread birds across Europe, showing no signs of the rapid declines that would warrant a threatened category.
- **Population:** Roughly 20 to 44 million breeding pairs in Europe, with a global population of many tens of millions of mature individuals.
- **Trend:** Stable
- **Assessed:** 2018
- **CITES:** Not listed on CITES
- Although abundant, blue tits remain sensitive to local pressures such as habitat loss, reduced insect food from pesticide use, and mismatches between chick-rearing and the timing of caterpillar peaks as springs warm.

## Key facts: Blue Tit
- The blue tit is a small blue-capped, yellow-breasted songbird widespread across Europe and into western Asia and North Africa.
- It is listed as Least Concern by the IUCN, with a large and broadly stable European population.
- Agile and acrobatic, it forages upside-down on thin twigs and is a confident visitor to garden feeders.
- Blue tits famously learned to peck open foil milk-bottle tops in Britain, a behaviour recorded from the 1920s.
- They are cavity-nesters that readily use nest boxes, laying unusually large clutches of up to a dozen or more eggs.
- Breeding is finely timed so chicks hatch during the spring peak in caterpillar abundance.

## What does a blue tit look like?
The blue tit is among the most colourful small birds in Europe, and its palette makes it hard to confuse with anything else at a feeder. Adults have a bright blue crown bordered by a white forehead and cheeks, a thin dark line running through the eye, and a dark bib beneath the bill. The back is a soft yellow-green, the wings and tail are blue, and the underparts are a vivid yellow, often with a faint dark stripe down the belly. Males and females look broadly alike, though males tend to show slightly more brilliant blue, which is enhanced by ultraviolet reflectance that birds can see but humans cannot. It is a compact bird, measuring 10.5 to 12 centimetres in length with a wingspan of roughly 17.5 to 20 centimetres, and weighing only about 11 grams. Juveniles are duller and greener, with yellowish rather than white cheeks. The combination of blue cap, white face and yellow breast, together with its small size and restless, acrobatic movements, makes the blue tit one of the easiest garden birds to identify with confidence.

## Where do blue tits live and what do they eat?
Blue tits are found across most of Europe, extending into parts of western Asia, the Middle East and north-west Africa. They favour deciduous and mixed woodland but adapt readily to parks, hedgerows, orchards and gardens, which is why they are such a familiar presence around homes. Most are resident year-round rather than long-distance migrants, though some northern and eastern birds move in response to harsh winters. Their diet shifts with the seasons. In spring and summer they feed heavily on insects, spiders and other small invertebrates, with caterpillars especially important for feeding nestlings. Outside the breeding season they broaden their menu to include seeds, fruits and nuts, and they are enthusiastic users of garden feeders stocked with sunflower seeds and fat. This adaptability and willingness to exploit human-provided food has helped the species remain abundant. Their boldness around people also produced one of ornithology's most famous learned behaviours: from the 1920s, British blue tits learned to peck through the foil caps of doorstep milk bottles to reach the cream beneath, a habit that appeared to spread through populations before doorstep deliveries declined.

## How do blue tits breed and nest?
Blue tits are cavity-nesters. In the wild they use holes in trees and walls, but they take very readily to garden nest boxes, which has made them a favourite subject for nest-cam watchers. The female builds a cup of moss, grass and other plant material, lining it with hair, wool and feathers. Blue tits lay notably large clutches for their size, typically around seven or eight eggs but sometimes a dozen or more; exceptionally large single-female clutches have been verified in Britain. They usually raise a single brood each year, and the timing is critical: laying is judged so that the hungry chicks hatch to coincide with the spring flush of caterpillars, the key food for growing young. A pair may need to deliver hundreds of caterpillars a day to feed a full brood. This tight link between breeding and caterpillar abundance makes blue tits a useful indicator of how warming springs are shifting the timing of natural events. Most blue tits live only a few years, with high mortality among young birds, although ringing has shown individuals can reach ten years or more.

## Blue tit vs great tit
| Feature | Blue tit | Great tit |
| --- | --- | --- |
| Size | Smaller, about 11 g | Larger, about 18 g |
| Head | Blue cap, white cheeks | Black head, white cheeks |
| Breast | Yellow, no bold stripe | Yellow with bold black central stripe |
| Wings | Blue | Blue-grey with white wing-bar |
| Voice | High, trilling notes | Loud, ringing two-note 'teacher-teacher' |
| Behaviour | Acrobatic, hangs from thin twigs | Bolder and more dominant at feeders |

## What WARN does
World Animal Rescue Network does not run field projects specifically for the blue tit, which is a common and widespread species well outside WARN's five partner countries. This guide is part of WARN's free educational work, written to help people understand and value the wildlife around them. The threats that do affect blue tits in places, such as habitat loss, pesticide use that reduces insect food, and the changing timing of seasons, are the same broad pressures that bear down on the more vulnerable animals WARN does work to protect.

If learning about the blue tit brought you a moment of joy, you might consider supporting the educational and rescue work that helps people protect wildlife everywhere.

## Frequently asked questions: Blue Tit
### What is a blue tit?
A blue tit (Cyanistes caeruleus) is a small European songbird in the tit family, recognised by its blue cap and wings, white cheeks and bright yellow breast. Weighing only about 11 grams, it is one of the most common and acrobatic visitors to garden feeders across Britain, Ireland and much of Europe, and is listed as Least Concern by the IUCN.

### What do blue tits eat?
Blue tits eat mainly insects, spiders and other small invertebrates, with caterpillars being especially important for feeding their chicks in spring. Outside the breeding season they also take seeds, nuts and fruit, and they are keen users of garden feeders, particularly those offering sunflower seeds and fat balls. This varied, adaptable diet helps them thrive in gardens and woodland alike.

### Are blue tits and great tits the same bird?
No. Blue tits and great tits are closely related but distinct species. The blue tit is smaller, weighing around 11 grams, with a blue cap and a yellow breast. The great tit is noticeably larger and bolder, with a glossy black head, white cheeks and a black stripe running down its yellow front. Both visit garden feeders and nest in boxes, often together.

### Do blue tits really open milk bottles?
Yes, historically they did. From the 1920s, blue tits in Britain learned to peck through the foil caps of doorstep milk bottles to reach the cream beneath, and the behaviour appeared to spread through local populations. It became one of ornithology's most cited examples of learning in wild birds. The habit faded as doorstep milk deliveries in glass bottles declined.

### How long do blue tits live?
Most blue tits live only a few years, and mortality is high among young birds in their first winter. However, individuals can live much longer: bird-ringing has recorded blue tits reaching around ten years of age in Britain, with the longevity record for the species standing at over eleven years. Survival depends heavily on winter weather and the availability of food.

### Will blue tits use a nest box?
Yes. Blue tits are natural cavity-nesters and take readily to garden nest boxes with a small entrance hole of about 25 millimetres, which excludes larger birds. A female lines the box with moss, hair and feathers and typically lays a large clutch in spring, raising a single brood timed to the seasonal abundance of caterpillars. Nest boxes are a reliable way to attract them.

## Sources
- [Eurasian blue tit - Wikipedia](https://en.wikipedia.org/wiki/Eurasian_blue_tit)
- [IUCN Red List - Cyanistes caeruleus](https://www.iucnredlist.org/species/22735965/87411190)
- [Cyanistes caeruleus - Encyclopaedia Britannica](https://www.britannica.com/animal/blue-tit)
- [Eurasian Blue Tit - Cornell Lab (Birds of the World)](https://birdsoftheworld.org/bow/species/blutit/)
- [Wikidata - Cyanistes caeruleus (Q25435)](https://www.wikidata.org/wiki/Q25435)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/blue-tit