By Joanna Chin
Anyone can identify a gull, but did you know that there are over 50 species of gulls worldwide? And do you know which gull species live near you, and how to tell them apart?
March is Gull Month at International Bird Rescue, and we think a good way to celebrate this month is to learn how to identify some of our local gull species! We’re going to look only at adult plumage here, since all gulls have juvenile plumages that can make identification tricky for even the most experienced of birders. We’ll start with the basics of five gull species in California.
Please note that there are more than five species of gulls in the state, but the ones we’re going to concentrate on are some of the more common and distinctive. If you are interested in more gull information, the Cornell Lab of Ornithology has wonderful information on the family Laridae (which includes gulls and their close relatives, terns and skimmers)!
The Western Gull is one of the most common gull species on the California coast. It is a large gull with a fairly dark gray back, black primaries (the feathers at the tips of the wings), pink feet, a yellow orbital ring (the narrow ring of flesh around the eye), and a sturdy yellow bill with a bright red spot on the mandible (lower half of the bill) called the gonydeal spot. This red dot serves a special purpose: It’s a target that the gull chicks peck at to entice the adult to regurgitate food for them. Although very common along the coast, Western Gulls are rarely seen more than two miles inland. These gulls do not migrate, and their appearance does not change during breeding season.
The Glaucous-winged Gull looks a lot like the Western Gull until you look carefully! For one thing, the Glaucous-winged Gull’s back is a much lighter gray. Also, this gull has no black at all—the primaries (wingtips) are the same light gray as its back— and both its legs and its orbital ring are pink. Like the Western Gull, The Glaucous-winged Gull has a yellow bill with a red gonydeal spot. These birds breed along the northern Pacific Coast but head down the coast in the wintertime. You will often see them with some brown speckling on their head in the winter (something you’ll never see on a Western Gull). But just to make things complicated, Glaucous-winged Gulls hybridize with Western Gulls, producing a gull that looks somewhat like each of them! This happens frequently enough that these hybrids, which are common on Washington State’s Olympic Peninsula, have their own name: the Olympic Gull.
The California Gull travels farther inland than either the Western or Glaucous-winged Gull. It tends to hang out in parking lots, as well as near the coast. It is smaller than the Western or Glaucous-winged and has a medium-gray back with black primaries, yellow-green legs, and a red orbital ring. Its eye is very dark (much darker, in fact, than the Ring-billed Gull I’ll discuss in a moment), it has a red gonydeal spot on the mandible of its bill, and it has a black ring near the tip of its bill. The corners of its mouth turn downward a bit, giving it a distinctive “frowning” expression! Like the Glaucous-winged Gull, the California Gull has brown speckling on its head in winter.
The Ring-billed Gull lives in California during the winter (non-breeding) season and migrates to the northern U.S. and Canada during the summer to breed. It is just slightly smaller than the California Gull and has a medium-gray back, black primaries, bright yellow legs, and a red orbital ring. It also has bright yellow irises, giving the Ring-billed Gull a very “beady-eyed” appearance. Its bill is yellow with a thick black ring around it, and there is no red whatsoever. In winter, when this gull is in California, it has the brown speckling on its head. Like the California Gull, the Ring-billed Gull is found on the coast, as well as farther inland and in parking lots.
The Heermann’s Gull is unlike any other gull you’ll find in California. It winters in the state but migrates to Isla Rasa, a small island in the Sea of Cortez near Baja, California, every summer to breed. In breeding plumage, the Heermann’s Gull’s back is dark gray, the remainder of its body is light gray, its primaries are black, and its head is pure white. It has black legs, a red orbital ring, and a red bill with a black tip. In the winter, when this gull returns from breeding, its head is heavily speckled with gray. Heermann’s Gulls are known to employ a feeding strategy called kleptoparasitism, which means they steal food from other birds, most commonly the Brown Pelican. Sometimes they are seen landing on a pelican’s head and reaching right into its pouch to steal fish! The Heermann’s Gull is, unfortunately, quite susceptible to climate change. Because it nests almost exclusively on a small island in the Pacific Ocean, events such as El Niño and “the Blob” (an unusually large mass of warm water in the Pacific Ocean) can reduce the supply of food and influence breeding success. In fact, the Heermann’s Gull has had near total breeding failure for the past two years. Conservation efforts and swift action to slow climate change are critical to preserving this gorgeous species.
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