Heermann’s Gulls, California
By Charlie • January 10, 2006 • 1 comment
Heermann’s Gull Larus heermanni
Santa Cruz, California. January 2006
One of the most distinctive gulls in North America, Heermann’s Gulls nest mainly in western Mexico (estimates suggest that of the current population of about 150,000 pairs, 90% nest on the island of Isla Rasa, Mexico, with smaller colonies as far north as California). In late May, after their early breeding season, Heermann’s Gulls migrate north along the Pacific Coast. Their migration coincides with that of the Brown Pelican from whom they often steal food. Post breeding dispersal occurs commonly to central California, and less commonly north as far as British Columbia and south as far as Guatemala.
The species spends the non-breeding season in a variety of coastal habitats, including rocky shores, bays, small offshore islands, kelp beds, sandy beaches, and estuaries, seldom spending time at garbage dumps or on fresh water.
All of the birds below are moving into full breeding plumage - either with some dark, adult winter/non-breeding “freckling” still on the head or with the gleaming white feathers of the full breeding plumage (an unusual progression for such a dark gull which results in the head being the only part of this species that is white in the breeding plumage).
Image 1
Image 2
Image 3
Image 4
Image 5
Image 6 (with a Western Gull Larus occidentalis)
Image 7
Image 8
Image 9
Image 10.
(Note the worn wing coverts and (presumably still growing) secondary feathers of the bird in Image 10:
compared with the bird directly above (Image 9) this individual showed a much-reduced white trailing edge in flight, though has a cleaner, ‘more-advanced’ head.)
All photographs © Charlie Moores
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To me, the second coolest thing about Heermann’s Gulls, after their astounding beauty, is that they are named after a syphilitic engineer! Ornithologists rule!