How to identify the Gull

To correctly identify the Gull (Larus spp.), 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

25-79 cm (10-31 in)

Wingspan

61-170 cm (24-67 in)

Weight

100-2000 g (3.5 oz - 4.4 lbs)

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Adult plumage typically features a white head and underparts, grey mantle (back and upperwings), and black wingtips, often with white 'mirrors'. Some species have dark heads (e.g., Black-headed Gull, Laughing Gull) during breeding season. Juvenile plumage is highly variable, often mottled brown or grey, gradually acquiring adult plumage over 2-4 years depending on the species.

2. 2

   Beak shape

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

   Strong, slightly hooked bill, typically yellow with a red spot on the lower mandible in many large species (e.g., Herring Gull), or dark red/black in others. Bill size and color are important identification features.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Typically dark, but can be pale yellow or reddish in some species, often with a distinct orbital ring (red, yellow, or orange).

4. 4

   Leg color

   Leg and foot color.

   Varies by species: pink, yellow, greenish-yellow, or dark red/black.

5. 5

   Distinguishing features

   Standout features that separate this species.

   Overall size, mantle color (shade of grey), wingtip pattern (extent of black and white mirrors), bill size and color, leg color, and head pattern (hooded vs. white-headed) are key. The primary projection beyond the tail at rest is also useful.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juveniles are typically mottled brown, grey, or dusky, often with dark bills and legs. They undergo several molts, gradually transitioning through various immature plumages (first-winter, second-winter, etc.) before reaching full adult plumage. The exact sequence and appearance vary significantly between species.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   Many species exhibit seasonal changes, most notably 'hooded' gulls (e.g., Black-headed Gull, Laughing Gull) which develop a dark brown or black head during the breeding season and revert to a white head with a dark ear spot in non-breeding plumage. White-headed gulls generally show less dramatic seasonal changes, primarily involving head streaking in winter.

8. 8

   Sexual dimorphism

   How males and females differ.

   Generally minimal, with males often slightly larger than females, but plumage is usually identical. Voice can sometimes differ slightly.

Key field marks

• Size and Shape. Note the overall size (small, medium, large) and body proportions. Is it slender or robust? Does it have a long neck or short legs?
• Mantle Color. Observe the color of the back and upperwings. Is it very pale grey, medium grey, or dark grey/black? This is a primary field mark for many species.
• Wingtip Pattern. Crucial for identification. Note the extent of black on the primary feathers, the presence and size of white 'mirrors' (spots) on the wingtips, and the pattern of white trailing edges.
• Head Pattern. Is the head entirely white, streaked with grey/brown (winter plumage), or entirely dark (hooded gulls in breeding plumage)? Note any distinct dark ear spots or eye-rings.
• Bill Color and Shape. Note the color (yellow, red, black, bicolored) and the presence of a red or black spot on the lower mandible. Is the bill slender or heavy? Long or short?
• Leg Color. Observe the color of the legs and feet (pink, yellow, greenish, black, red). This can be a definitive feature for some species.
• Juvenile/Immature Plumage. Be aware that gulls take several years to reach adult plumage. Learn the distinct juvenile and various immature plumages for common species in your area, as they often look very different from adults.
• Vocalizations. Learn the distinctive calls of different gull species. Their 'voices' can be very helpful, especially for species that are difficult to distinguish visually.
• Behavior and Habitat. Consider where you are seeing the gull (coastal, inland, urban) and what it is doing (foraging, resting, flying). This context can help narrow down possibilities.

Explore the Gull