Heermann’s Gull

Identification

Heermann's gull is unmistakable among North American west coast gulls. Adults display a distinctive medium gray body with blackish-gray wings and tail edged in white, a bright red bill tipped with black, and a dusky gray head in non-breeding plumage that becomes white during breeding season. Immatures are darker and browner than non-breeding adults, with pink bills until their second winter. Rare individuals—approximately 1 in 200—show white primary coverts that create a striking spot on the upper wing. This is the only white-headed, gray-bodied gull found on the west coast of North America, making field identification straightforward.

Range & Habitat

Nearly the entire global population of approximately 150,000 pairs nests colonially on Isla Rasa in the Gulf of California, with smaller breeding colonies scattered from California south to Nayarit, Mexico. After breeding season, birds disperse widely: commonly to central California, occasionally north to British Columbia, and south to Guatemala. They inhabit coastal waters and open ocean, very rarely venturing inland. A small but established breeding colony persists in Seaside, California, having relocated to rooftops after nesting islands eroded.

Behaviour & Diet

Heermann's gulls nest colonially on the ground at remarkably high densities—up to 110 nests per 100 square meters. Each pair typically lays two or three grayish-buff eggs marked with gray and brown. A notable behavioral trait is their habit of stealing prey from other seabirds, particularly brown pelicans, with which they frequently associate. Their diet comprises small fish, marine invertebrates, lizards, insects, refuse, and carrion, making them highly adaptable foragers.

Best Time & Places to See It

Breeding birds concentrate on Isla Rasa from spring through summer, though the island remains difficult to access. Post-breeding dispersal makes them most visible to travelers along the California coast from late summer onward, particularly in central California waters. The Seaside, California breeding colony offers an accessible opportunity to observe nesting birds. Pelagic trips departing from California ports provide excellent chances to encounter this species at sea during winter months.

Photography Tips

The striking contrast between gray plumage and white head in breeding adults creates compelling photographic subjects. Capture birds in flight to showcase the distinctive white-edged dark wings and tail. Coastal perches and feeding interactions with brown pelicans offer dynamic shooting opportunities. Winter plumage dulls the head coloration, so breeding season visits to accessible colonies yield the most visually distinctive images. The red bill with black tip and rare white wing-covert variants provide excellent details for close-up photography.