Do You Know Your Seagulls?

A mature herring gull. Picture courtesy of and © Paul Babb 2013.
A mature herring gull. Photo: Courtesy of and © Paul Babb 2013

Seagulls are by far the most common bird along the coast near Santa Cruz, California. There are dozens of different seagull species, and you need a keen eye to tell them apart. To make things even more challenging, gulls change color with age and with the season. It’s almost impossible to identify the species of a juvenile gull because they all look very similar.

Sometimes called “sky rats,” seagulls are omnivores. They are opportunistic feeders who will eat just about anything, alive or dead. They keep the beaches from piling up with rotting matter and are an important part of the marine ecosystem. The three most common gulls in the Santa Cruz area are the California gull, the western gull, and the Heermann’s gull. You might see others, too, such as the pink-footed herring gull (Larus argentatus).

California Gull

The California gull (Larus californicus) is a medium-sized gull, less than two feet long, with a wingspan of four feet. It is distinguished by its yellow bill, which has a black ring near the tip with a red spot on the underside.

A California gull, June 30 2010. Photo by Dick Daniels and courtesy Wikimedia Commons.
A California gull, June 30, 2010. Photo: Courtesy of Dick Daniels, CC BY-SA 3.0

This seagull ranges along the West Coast, from southern British Columbia to southern Mexico. It also goes inland as far north as northern Canada and east to North Dakota and Kansas, where it likes to breed and nest in the spring, especially on lakes. The female lays two or three eggs in a shallow depression lined with feathers and vegetation. Both parents take turns feeding the young and guarding the nest.

Western Gull

A large gull, the western gull (Larus occidentalis) is over two feet long, with a wing span of over four feet. A common sight from Canada to Mexico, they rarely go inland. If there is food available, they might stay year-round, or they might migrate south in the winter.

A western gull. Picture courtesy of and © Paul Babb 2013.
A western gull. Photo: Courtesy of and © Paul Babb 2013

You can tell a western gull by its yellow bill, which has just an orange spot on the end of the lower beak (no black ring like a California gull). Although the male is larger than the female, they have similar plumage.

Colonies of nesting pairs establish a territory on an isolated island or on rocky cliffs and build nests on the ground. The female lays three eggs, and the male and female take turns incubating them for a month.

Heermann’s Gull

The Heermann’s gull (Larus heermann) is easier to identify than most gulls. It has darker, sooty-gray plumage, a white head, and a bright reddish-orange bill with a black-tipped beak. It can be confused with the parasitic jaeger (Stercorarius parasiticus) and, like the jaeger, will steal the catch of other birds.

A Heermann’s gull. Picture courtesy of and © Paul Babb 2013.
A Heermann’s gull. Photo: Courtesy of and © Paul Babb 2013

They are coastal birds, ranging from southern British Columbia to Central Mexico. They migrate south in December. The majority (about 90%) nest on an island, Isla Rasa, in the Gulf of Mexico. They are the only gull that breeds south of the US-Mexico border.

An immature gull. Gulls are hard to identify to the species level when young. Picture courtesy of and © Paul Babb 2013.
An immature gull. Gulls are hard to identify at the species level when young. Photo: Courtesy of and © Paul Babb 2013

Take the Self-Guided Mobile Tour

This piece is part of the Marine Life Guide. Download the free app with many tours of the Santa Cruz area and beyond.


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  1. Sources Used

      • All About Birds. Cornell Lab of Ornithology website.
      • Birds. Channel Islands National Park. US National Park Service website.
      • Birds of North America. website.
      • Birds. National Audubon Society Birds website.
      • Heermann’s gull video. ARKive website.
      • Personal communication with Patrick Wilkinson, a volunteer and docent for Seymour Marine Discovery Center at Long Marine Lab and Bay Net, volunteer organizations under the auspices of the Monterey Bay National Marine Sanctuary.

About The Author

I really enjoy field trips. I love being in a cool place and having someone tell me about it. The problem is, you can’t always find a professor or park ranger-type to tell you all they know about the local rocks, plants, and history. So I decided to combine my love of things natural with mobile technology.

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  1. Raymond

    Hi: This week I saw large groups of gulls in winged formation flying east from San Francisco Bay as I was commuting over the Sunol grade around 9am. Hundreds, maybe even more in tight groups. Is this a sign of a mass migration? I thought they went toward the coast in Fall not away from it…

    Thanks for any info,

    1. Alex

      I’ve observed the same behavior down here in Orange County every year. I’ve noticed that around November, seagulls will form tight flocks and come as far inland as Palm Desert at least. They’ll eventually disperse inland, and in March they come back together in their tight flocks and head back to the ocean.

  2. Mikey

    Extensive research has shown that it takes three sea gulls of any specie to eat a french fry slathered in Tabasco sauce


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