General
Heermann's Gull: Medium-sized gull with gray underparts and dark gray upperparts. Head is white and bill is bright red with black tip. Tail is black and edged with white. Legs and feet are black. Sexes are similar. Winter adult is similar but has gray and white mottled head. Juvenile and 1st winter are dark brown with darker flight and tail feathers, and pale black-tipped bill. 2nd winter resembles juvenile, but is more uniformly dark brown and shows thin white edges on tail and wings; bill is red with black tip.
Range and Habitat
Heermann's Gull: Nests on hot desert islands along the coast of western Mexico, and migrates northward to the Pacific coast of North America as far north as southern British Columbia; it may disperse southward from Mexican breeding grounds. Found along beaches, rocky shoreline, estuaries, and lagoons.
Breeding and Nesting
Heermann's Gull: Two or three pale blue gray eggs with lavender, brown, and blue marks are laid in a nest made of sticks and small rocks, sometimes lined with feathers, and built on the ground or between large rocks and boulders. Eggs are incubated for 28 days by both parents.
Foraging and Feeding
Heermann's Gull: Feeds mostly on small fish such as sardines and anchovies, occasionally on crustaceans, mollusks, and other marine invertebrates scavenged from the beach, kelp beds, and fishing boat dumps.
Vocalization
Heermann's Gull: Makes a "kwak" and a high-pitched "weee", nasal and whiny.
Similar Species
Heermann's Gull: No other North American gulls have a sooty gray body and a white head.