How to identify the Eurasian Blue Tit

To correctly identify the Eurasian Blue Tit (Cyanistes caeruleus), check each of these features. Birds can be tricky: habit, habitat, and call often confirm a sighting that a single photo cannot.

Size at a glance

Length

10.5-12 cm

Wingspan

17.5-20 cm

Weight

7.5-12 g

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Adults have a bright blue crown, nape, and wings, with a white face bordered by a dark blue-black eye-stripe and collar. The back is greenish-blue, and the underparts are bright yellow with a narrow dark line down the belly. The tail is blue. The wing-bar is white.

2. 2

   Beak shape

   Shape and color of the bill: a key field mark.

   Small, conical, and pointed; dark grey to black.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Dark brown.

4. 4

   Leg color

   Leg and foot color.

   Dark grey to bluish-grey.

5. 5

   Distinguishing features

   Standout features that separate this species.

   The combination of a bright blue cap, white cheeks with a dark eye-stripe, and yellow underparts with a dark belly stripe is distinctive. The white wing-bar on blue wings is also a key feature.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juveniles are duller than adults, with a yellowish-green crown and cheeks, and duller yellow underparts. The blue areas are less vibrant, and the eye-stripe is less defined. They lack the crisp white wing-bar of adults, which is often yellowish.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   No significant seasonal plumage changes. Plumage may appear slightly duller after breeding due to wear, but no distinct non-breeding plumage.

8. 8

   Sexual dimorphism

   How males and females differ.

   Males tend to have slightly brighter plumage, particularly the blue on the crown and the yellow on the breast, and a broader, darker belly stripe. However, these differences are subtle and often difficult to discern in the field.

Key field marks

• Size and Shape. Small, plump, and compact with a relatively short tail and a small, pointed bill.
• Head Pattern. Look for the distinctive bright blue cap, white cheeks, and a dark blue-black eye-stripe extending to a collar around the nape.
• Body Plumage. Bright yellow underparts with a narrow dark line down the belly. Greenish-blue back. Blue wings with a single white wing-bar.
• Behavior. Observe its acrobatic feeding style, often hanging upside down. It is very active and restless.
• Vocalizations. Listen for its characteristic high-pitched, tinkling song ('tsee-tsee-tsee-tsooit') and sharp 'tink' calls.

Explore the Eurasian Blue Tit