The California gull (Larus californicus) is a medium-sized gull that breeds primarily in the interior of western North America. It is fairly common along the California coast and can be found inland around lakes, rivers, and fields across much of the western United States. Identifying the California gull is easiest during the breeding season when the adults have bright red rings around their eyes. However, with some practice, the California gull can be recognized year-round based on a combination of size, structure, plumage details, and behavior. This article will walk through the key identification features of the California gull to help you distinguish it from other similar gull species.
Distinguishing Features
Some key features to look for when identifying a California gull are:
Size
– About the size of a Ring-billed Gull, although a bit slimmer in structure. Length 19-22 inches.
Wings
– Gray back and upper wing coverts. Black wingtips with small white “mirrors” at the tips of the outer 3-4 primaries. Wingspan 49-55 inches.
Adult Breeding (March-August)
– Bright red ring around eyes. Yellow bill with red spot. White head, breast, and underparts. Gray back and wings. Black wingtips with white spots. Pink legs.
Adult Nonbreeding (Fall & Winter)
– Eyes dark. Pale ring around eyes less distinct. Bill yellow with black tip. Head white with variable gray streaking around eyes and back of head. Breast and belly white. Back and wings gray. Black wingtips with white spots. Pink legs.
Juvenile
– Gray-brown overall with darker wings. Eyes dark. Bill black. White tail with black terminal band. Legs pinkish. Acquires adult plumage by 2nd year.
Behaviors
– Buoyant flight style with slower, deeper wing beats compared to other white-headed gulls. Often hovers when hunting. Will soar and glide low over land.
– Voice is a laughing “keeh-keeh-keeh” call. Also gives high, squealing “keee-aah” notes.
– Found in both coastal and inland habitats throughout much of western North America. Nests colonially in the interior at lakes, rivers, and wetlands. Winters along the Pacific coast.
– Omnivorous; feeds on fish, crabs, garbage, insects, eggs, berries, and more. Opportunist and scavenger.
So in summary, the combination of medium size, gray back, black wingtips with white spots, pink legs, and red eye ring in breeding plumage can help identify the California gull. Keep an eye out for that bright red orbital ring around the eye when seeing gulls along the California coast!
Similar Species
The California gull resembles several other gull species, especially when not in its bold breeding plumage. Here’s a quick comparison to some common lookalike species:
Ring-billed Gull
– Very similar in size and structure to the California gull.
– Adult has yellow bill with black ring. Yellow or flesh-colored legs.
– Lacks California gull’s red eye ring in breeding plumage.
– More common along northern coasts than California gull.
Herring Gull
– Significantly larger than California gull.
– Bill larger and chunkier with reddish spot.
– Legs pink.
– Adult has yellow eyes with red orbital ring.
– Juvenile darker gray-brown overall.
Mew Gull
– Smaller with a more rounded head.
– Adult bill is yellow with red spot. Legs red.
– Breeding plumage has red orbital ring.
– Smaller size and rounded head distinguish from California gull.
Heermann’s Gull
– Similar in size to California gull. Gray mantle and wings.
– Legs pink. Bill red with black tip.
– Breeding adult has red eyes but no orbital ring.
– Coastal species that lacks California gull’s inland distribution.
Range and Habitat
The California gull has a fairly widespread range across western and central North America:
Breeding (March-August)
– Nests inland at lakes, rivers, wetlands, and islands.
– Colonies found across interior western North America into the northern Great Plains.
– Highest concentrations in Utah, Nevada, Idaho, Wyoming, Alberta, and Saskatchewan.
Wintering
– Winters along the Pacific Coast from southern British Columbia to Baja California.
– Also found wintering inland at reservoirs, landfills, and open fields.
Migration
– Migrates between coastal and inland habitats.
– Spring migration March-May. Fall migration September-November.
Vagrancy
– Uncommon but regular vagrant to the East Coast and interior eastern North America.
So in summary, look for the California gull in western North America year-round, especially in coastal areas in winter and at inland lakes and wetlands in summer. Its range overlaps with several similar gull species, so be sure to pay close attention to the key identification features.
Appearance Details
Here is more detail on the California gull’s appearance and how it changes throughout the year:
Measurements
– Length: 19-22 inches
– Wingspan: 49-55 inches
– Weight: 1.1-1.4 lbs
Plumage Details
Adult Breeding (March-August)
– Head: White with variable gray smudging around eyes and rear of head. Bright red orbital ring. Yellow bill with red subterminal spot. Eyes brown.
– Back: Pale gray mantle. Upperwing coverts medium gray.
– Underparts: Breast, belly, and tail white.
– Wings: Black primaries and primary coverts. White mirrors on outer 3-4 primaries. Gray secondaries and coverts. White trailing edge to secondaries forms distinct white crescent in flight.
– Legs: Pink
Adult Nonbreeding (Fall & Winter)
– Head: White with variable dusky streaking around eyes and rear of head. Pale pinkish orbital ring. Yellow bill with black tip. Eyes brown.
– Back: Mantle and wings as breeding plumage.
– Underparts: Breast and belly white.
– Wings: Black wingtips.
– Legs: Pink
First Year (Juvenile)
– Head: Dark eye. Black bill. Brownish overall.
– Back: Brownish-gray mantle. Blackish flight feathers and wing coverts.
– Underparts: Whitish breast with variable brown streaking. Belly white.
– Wings: Dark gray-brown. White tail with black terminal band. White trailing edge to secondaries.
– Legs: Pinkish
Second Year
– Variable mix of first year and adult plumage. Often showing some pinkish on bill and pale eye ring. May take 3 years to reach full adult plumage.
Molt
– Complete molt of all feathers in late summer after breeding season.
– First year birds may take 2-3 years to reach full adult plumage through partial molts.
– Bills often worn down during breeding season from feeding chicks and regrow during molt.
So in summary, look for the bright red eye ring and clean white head of breeding adults. Nonbreeding birds have variable dusky streaking on the head and a less obvious pale eye ring. The pink legs combined with medium size help distinguish California gulls year-round.
Behavior and Feeding
The California gull exhibits some key behaviors that can aid in identification:
Flight Style
– Buoyant flight interspersed with slow, deep wingbeats.
– Distinctive flight profile with wings held straight and flat.
– Often hovers when hunting. Will dip down to surface while hovering to grab prey.
– Soars and glides low over land. Less aerial than similar gull species.
Voice
– Laughing, squealing “keeh-keeh-keeh” calls given in flight and at colonies.
– High, squealing “keee-aah” alarm calls.
– Various barks, mews, and gurgling notes at nesting colonies.
Behavior
– Gregarious. Nests colonially. Roosts communally.
– Opportunistic feeder. Scavenges at landfills and urban areas.
– Kleptoparasitism common, will steal food from other birds.
– Male selects nest site and defends small territory around nest.
Diet
– Omnivorous and varied diet.
– Feeds on insects, fish, crustaceans, eggs, small mammals, berries, garbage, carrion.
– Forages in intertidal zones, shores of lakes/rivers, wetlands, fields, parking lots.
– Very adaptable and will take advantage of any available food source.
In summary, the California gull has a more methodical flight style compared to other similar gulls. It is very opportunistic in its feeding habits and readily adapts to take advantage of urban areas and human food sources.
Breeding and Nesting
The California gull nests colonially in large numbers at inland lakes and rivers:
Nesting Habitat
– Nests on the ground in colonies on islands in lakes and rivers.
– Island and peninsula nest sites provide protection from mainland predators.
– Vegetation includes bulrushes, cattails, grasses.
– Alkaline and brackish lakes and marshes used regularly.
Nest Description
– Bulky nest built on ground from available vegetation.
– Nest lining includes grasses, reeds, rushes, twigs.
– Nest cup approximately 5-6 inches across and 2-3 inches deep.
– Males select territory and build initial nest. Pairs add material together.
– Nests spaced 2-3 feet apart in dense colonies.
Clutch Size
– Typical clutch size is 2-3 eggs (range 1-4)
– Egg color light brown to olive with dark brown speckles
– Egg size: 2.2 x 1.5 inches
– Laying interval: 2 days
– Incubation: 3 weeks
– Fledging: 4-5 weeks
Parental Care
– Both parents incubate eggs. Female typically initiates incubation.
– Eggs and chicks heavily predated by coyotes, foxes, mink.
– Semi-precocial chicks; leave nest within 1-2 days.
– Parents feed chicks initially by regurgitation.
– Chicks form creches for protection while parents forage.
So in summary, look for California gull nesting colonies on protected islands at inland lakes and wetlands across the western interior during the summer breeding season from March-August. Nests are bulky constructions built on the ground in dense colonies.
Conservation Status
The California gull has an extensive range and large total population. It is considered a species of least concern by conservation organizations:
Population Estimate
– Global population estimated at 300,000-500,000 individuals
Population Trend
– Increased dramatically in 20th century with creation of reservoirs across western North America
– Stable currently but subject to large fluctuations at breeding colonies
Major Threats
– Human disturbance at nesting colonies
– Introduced predators at nesting islands
– Contamination from pesticides, heavy metals, botulism
– Entanglement in fishing gear
Conservation Actions
– Protect nesting islands from disturbance and encroachment during breeding season
– Control predators such as foxes, coyotes, raccoons at key nesting sites
– Monitor for effects of environmental contaminants
– Public education to reduce feeding gulls and garbage availability at urban sites
Overall, the California gull remains widespread and locally abundant. Conservation should focus on protecting key breeding colonies and monitoring for potential threats. This adaptable species takes readily to human-altered habitats.
Where and When to See in California
Some of the best places to spot the California gull in its namesake state include:
San Francisco Bay
– Large numbers winter along shores and at landfills.
– Check Marina Green, Fisherman’s Wharf, beaches.
– Also try Santa Cruz and Monterey coastal areas.
Salton Sea
– Important inland wintering site. Scan flocks of gulls at lakeshore parks.
– Nesting colonies found on islands when water levels allow.
Central Valley
– Winter foraging flocks at reservoirs, agricultural fields, landfills.
– Breeds at marshes when conditions allow, such as Kern NWR.
Klamath Basin NWR
– Nesting colonies active March-July.
– View from observation tower near nesting islands.
Mono Lake
– One of largest breeding colonies in California.
– Nesting islands visible from shore. Prime viewing May-July.
Look for wintering California gulls along the entire California coast from July-April. Breeding colonies occur at inland lakes and wetlands during May-July. Be respectful of nesting birds and view from a distance.
Conclusion
In summary, the California gull is a medium-sized white-headed gull that inhabits western North America year-round. Look for the distinctive pink legs, gray mantle, black wingtips with white spots, and bright red orbital ring around the eye in breeding plumage. Getting a good view of the wings and head pattern helps distinguish the California gull from similar species. This adaptable gull can be found along the California coast in winter and nesting colonially at inland lakes during summer. With some practice, birders can readily identify the California gull by paying attention to size, structure, plumage details, behavior, and range. The California gull remains widespread but faces threats at some breeding colonies. Birders can contribute to conservation by respecting nesting birds and participating in surveys. With its buoyant flight and squealing calls, the California gull adds its own unique presence to both coastal and inland habitats across the western states and provinces.