Heermann's gull is a gull resident in the United States, Mexico and extreme southwestern British Columbia, nearly all nesting on Isla Rasa in the Gulf of California. They are usually found near shores or well out to sea, very rarely inland. The species is named after Adolphus Lewis Heermann, nineteenth-century explorer and naturalist.
Region
Northeast Pacific and Gulf of California
Typical Environment
Breeds mainly on rocky islands in the Gulf of California, especially Isla Rasa, and is commonly found along the Pacific shoreline from Mexico north through the U.S. West Coast to southwestern Canada. Outside the breeding season it frequents beaches, coastal lagoons, harbors, and offshore waters, rarely occurring inland. Often associates with fishing vessels and roosts on jetties, sand spits, and rocky points. Occurs over nearshore waters where upwelling concentrates prey and alongside flocks of Brown Pelicans.
Altitude Range
Sea level to 200 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
Nearly the entire world population breeds on tiny Isla Rasa in the Gulf of California, making the species highly vulnerable to disturbances and El Niño events. After breeding, large numbers disperse north along the Pacific coast to California, Oregon, Washington, and into British Columbia. They are famous for kleptoparasitism, often stealing fish from Brown Pelicans and other seabirds.
Juvenile, California
Playa Malecon, Puerto Vallarta, Jalisco, Mexico
Adult and fledgling by Roberts Lake in Seaside, California.
Temperament
social and active
Flight Pattern
strong flier with buoyant wingbeats and agile coastal maneuvers
Social Behavior
Breeds colonially, with dense ground nests concentrated on small islands. Pairs are typically monogamous within a season and both sexes share incubation and chick rearing. Outside breeding, they gather in flocks along beaches and around fishing activity, often interacting closely with other seabirds.
Migratory Pattern
Seasonal migrant
Song Description
Vocalizations are sharp, nasal, and scolding, with repeated kek and kerr notes typical of gulls. Calls intensify around nesting sites and during aggressive interactions or kleptoparasitic chases.
