How to identify the Willow Ptarmigan

To correctly identify the Willow Ptarmigan (Lagopus lagopus), 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

35-43 cm (14-17 in)

Wingspan

60-65 cm (24-26 in)

Weight

450-800 g (16-28 oz), males typically larger than females

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Highly variable seasonally. Summer plumage is mottled reddish-brown with fine black barring, providing excellent camouflage against tundra vegetation. Winter plumage is entirely pure white, except for black outer tail feathers and a black bill. Males in breeding season develop a prominent red comb above each eye.

2. 2

   Beak shape

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

   Short, stout, and conical, adapted for browsing vegetation. Black in color.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Dark brown.

4. 4

   Leg color

   Leg and foot color.

   Feathered white legs and feet (tarsi and toes) in all seasons, providing insulation and aiding movement over snow.

5. 5

   Distinguishing features

   Standout features that separate this species.

   Seasonal plumage changes, feathered feet, black outer tail feathers (visible in flight or when fanned), and the male's red supraorbital combs during breeding season.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juveniles resemble adult females in summer plumage but are generally duller, with finer barring and less distinct patterns. They undergo a rapid molt to white winter plumage.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   Undergoes three complete molts annually. Spring molt (partial) from white to breeding brown. Summer molt (complete) to non-breeding brown. Autumn molt (complete) to white winter plumage. This allows for optimal camouflage throughout the year.

8. 8

   Sexual dimorphism

   How males and females differ.

   Males are generally slightly larger than females. In breeding plumage, males have a more reddish-brown head and neck, and prominent red combs above the eyes, which are absent or much smaller in females. In winter, both sexes are pure white, making differentiation difficult without close inspection or behavioral cues.

Key field marks

• Plumage Coloration. Look for the dramatic seasonal changes: mottled reddish-brown in summer, pure white in winter. The black outer tail feathers are a key field mark in all plumages, especially in flight.
• Male's Red Combs. During the breeding season (spring/early summer), adult males display prominent red fleshy combs above their eyes. These are absent or very small in females and non-breeding males.
• Habitat. Willow Ptarmigan prefers shrubby tundra, willow thickets, and open boreal forest edges. If you are in high, rocky, barren alpine areas, it's more likely to be a Rock Ptarmigan.
• Vocalizations. Listen for the male's distinctive, loud, cackling 'go-back, go-back' song, especially during display flights in spring. This is a strong indicator of Willow Ptarmigan presence.
• Feathered Feet. All ptarmigan have feathered feet, which is a good general identification for the genus Lagopus, but doesn't distinguish between species. However, it's a useful feature to note.

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