Glaucous Gull vs California Gull

In short

The Glaucous Gull is a large, pale gull with a heavy bill, while the California Gull is smaller and more slender with a darker mantle. In flight, the Glaucous Gull shows no black on its wingtips, unlike the California Gull which has black wingtips with white spots. These differences are most apparent in adult birds.

Identification tips

1. Size and bulk: Glaucous Gull is larger and bulkier. 2. Wingtips: Look for black wingtips in California Gull, absent in Glaucous Gull. 3. Mantle color: Darker in California Gull. 4. Juvenile plumage: Glaucous Gull juveniles are paler. 5. Habitat: Consider the location; Glaucous Gulls are more northern.

Size

The Glaucous Gull is noticeably larger and bulkier than the California Gull.

Plumage

Adult Glaucous Gulls have a pale gray mantle and white wingtips, whereas adult California Gulls have a darker gray mantle and black wingtips with white spots. Juvenile Glaucous Gulls are uniformly pale with a pinkish bill, while juvenile California Gulls are more mottled with a darker bill.

Behaviour

Both species are opportunistic feeders, but the Glaucous Gull often scavenges more and is more likely to be seen pirating food from other birds.

Habitat

Glaucous Gulls are typically found in Arctic and sub-Arctic regions, often on tundra or coastal cliffs, whereas California Gulls are more common in inland lakes and coastal areas of the western United States.

Voice

Both species have similar gull-like calls, but specific vocal differences are not well-documented.