How to identify the Mute Swan

To correctly identify the Mute Swan (Cygnus olor), 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

125-170 cm (49-67 in)

Wingspan

200-240 cm (79-94 in)

Weight

Male: 9.5-14 kg (21-31 lb), Female: 8-11 kg (18-24 lb); exceptionally up to 23 kg (51 lb)

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Adults are entirely pure white. Juveniles (cygnets) are typically grey-brown, gradually molting to white over their first year, though a rare 'Polish' morph is white from hatching.

2. 2

   Beak shape

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

   Large, wedge-shaped bill. Adults have a bright orange bill with a prominent black knob (called a 'knob' or 'berry') at the base, which is larger in males (cobs) than in females (pens). The bill tip and cutting edges are black.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Dark brown

4. 4

   Leg color

   Leg and foot color.

   Blackish-grey

5. 5

   Distinguishing features

   Standout features that separate this species.

   The most distinctive features are the S-curved neck (often held in an elegant 'S' shape, especially when swimming), the orange bill with a black knob, and its generally silent nature compared to other swans. When swimming, it often holds its wings slightly raised over its back in a characteristic 'busking' posture, particularly when displaying or feeling threatened.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Cygnets are typically covered in grey-brown down, with a greyish-pink bill that gradually darkens to orange with a developing black knob. They retain some greyish feathers through their first winter before becoming fully white.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   No significant seasonal plumage changes in adults. The black knob on the male's bill may become slightly more prominent during the breeding season.

8. 8

   Sexual dimorphism

   How males and females differ.

   Males (cobs) are generally larger than females (pens) and have a noticeably larger black knob on their bill, especially during the breeding season. Otherwise, plumage is identical.

Key field marks

• Neck Posture. Look for the distinctive S-curve of the neck, especially when swimming. Other swan species typically hold their necks straighter.
• Bill Color and Knob. Identify the bright orange bill with a prominent black knob at the base. The size of the knob is larger in males.
• Plumage. Adults are pure white. Juveniles are grey-brown with a greyish-pink bill.
• Vocalizations. Listen for its relative silence, primarily hisses when agitated, and the characteristic 'singing' sound of its wings in flight. Absence of loud bugling calls helps distinguish it from other swans.
• Busking Display. Observe if the swan holds its wings arched over its back, especially when swimming or displaying. This 'busking' posture is typical for Mute Swans.

Explore the Mute Swan