6 Gulls of Monterey Bay: How to Identify Every Species You’ll See
October 27, 2026
Most visitors to the Monterey coastline lump every gull into one category: “seagull.” Local birders know better. Ten species can be found with relative ease in the Monterey Bay region during the course of a year, and each one has its own look, its own calendar, and its own personality.
Learning to sort out gulls in Monterey Bay opens up one of the more rewarding challenges in West Coast birding. Unlike the towering wingspans covered in guides to the largest birds in North America, gulls reward patience over size: subtle differences in bill color, leg color, and wingtip pattern separate one species from the next. This guide walks through the six gulls a patient observer is most likely to encounter around the bay, from year-round residents to winter visitors passing through on migration.
1. Western Gull
The Western Gull (Larus occidentalis) is the default gull of the Monterey coastline, and for good reason. Western Gulls are common throughout the year along the shores of Monterey Bay, especially on rocky shores, and down the Big Sur coast, and the Western Gull is the main species that nests on rooftops around the Monterey Peninsula, Moss Landing, and nearly any bluff or building within a mile of the coast.
Adults show a dark slate-gray back, black primaries, pink feet, and a heavy yellow bill marked by a bright red gonydeal spot on the lower mandible. A coastal resident often seen on wharves, jetties and docks, the western gull dresses in spectacular white plumage with a dark slate-gray mantle. Chicks peck at that red spot to trigger a feeding response from the parent, a detail that makes the bird’s anatomy functional as well as distinctive.
Western Gulls rarely stray far from salt water. They are very rare inland, with only a handful of records at the Salinas wastewater ponds, just seven miles upstream from the coast. Their feeding habits reveal a sharp, adaptable mind: to break open the shells of prey like sea urchins and clams, western gulls drop them from high in the air onto hard surfaces, and they harass cormorants and pelicans, forcing them to regurgitate their catch. That kind of behavioral flexibility is exactly what earns gulls a spot among the most intelligent birds in North America.
Pro Tip: Look for Western Gulls loitering near fish-cleaning stations at Monterey’s Municipal Wharf. Boat crews cleaning their catch reliably draw a crowd of opportunistic adults.
2. California Gull
The California Gull (Larus californicus) is easy to overlook next to a Western Gull, but the differences show up quickly once you know what to check. It is a medium-sized gull with a round head, a slender bill compared to other gull species, and long, pointed wings in flight. It sits larger than a Ring-billed Gull but smaller than a Herring Gull.
Breeding adults are distinctive at close range. Breeding adult California Gulls are white-headed gulls with a medium gray back, yellow legs, and a dark eye, and adults have a yellow bill with a small black ring and a red spot on the lower mandible that brightens during the breeding season. Nonbreeding adults instead show brown streaking on the head.
Monterey Bay hosts an active nesting population that surprises many first-time visitors. In Seaside, birders have the opportunity to see Heermann’s Gull and California Gull colonies nesting on buildings along Broadway Avenue and Del Monte Avenue. Away from the nest, these gulls are relentless generalists. California Gulls are strong, nimble fliers and opportunistic foragers that hunt on foot, from the air, and from the water, a foraging style shared by many species covered in our breakdown of what birds eat to survive.
3. Heermann’s Gull
No other gull on this list looks quite like the Heermann’s Gull (Larus heermanni). The Heermann’s Gull is unlike any other gull found in California, thanks to a color scheme that runs opposite the usual gull palette of gray-and-white.
In breeding plumage, the bird is striking. The back is dark gray, the rest of the body is light gray, the primaries are black, and the head is pure white, set off by black legs, a red orbital ring, and a red bill with a black tip. That crimson bill is one of the easiest features for spotting a bird with a red beak along the entire Central Coast. By winter, when the gull returns from breeding, its head turns heavily speckled with gray, a change that trips up birders expecting the crisp white head of summer.
The species’ life history is unusual for a California bird. 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. Feeding behavior is just as opportunistic as its cousins: Heermann’s Gulls are known to employ a feeding strategy called kleptoparasitism, stealing catches directly from pelicans rather than fishing for themselves.
Monterey Bay’s local population has an unusual backstory. In the 1990s, a small group began nesting on artificial islands at Roberts Lake in Seaside rather than returning to Baja. Extensive fishing in their natal waters, introduced chick-eating predators like rats, rising ocean temperatures, and sea-level rise have combined to pose a serious threat to the colony, and the 2016 breeding season saw a near-total failure of breeding efforts. Local birders continue to monitor the colony each summer.
4. Ring-billed Gull
The Ring-billed Gull (Larus delawarensis) is one of the most familiar gulls in North America, and Monterey Bay sees plenty of them in the colder months. Adults are clean gray above, with a white head, body, and tail, black wingtips spotted with white, yellow legs, and a yellow bill with a black band around it. Nonbreeding adults show brown-streaked heads instead.
Young birds take a while to grow into that clean adult look. During their first two years, Ring-billed Gulls are a motley brown and gray with a pink bill and legs. Local birding guides group this species with the region’s other easy-to-find gulls: a wise approach for beginners is to focus study on the most common species, including Western, Glaucous-winged, California, and Ring-billed Gulls, using them for comparison against less common visitors.
Ring-billed Gulls are far less tied to salt water than Western or Heermann’s Gulls. They often congregate around humans, at garbage dumps, parking lots, and freshly plowed fields, and while common on coastal beaches in winter, many lead inland lives, never setting eyes on the sea. That flexibility puts them in the same generalist category as many of the freshwater and coastal species profiled in our guide to water birds in Texas, where inland lakes and reservoirs attract similar wintering flocks.
Key Insight: Ring-billed Gulls reach adult plumage in about three years, faster than the four to five years needed by Western, California, and Glaucous-winged Gulls, which is one reason winter flocks show so many mixed plumages at once.
5. Glaucous-winged Gull
The Glaucous-winged Gull (Larus glaucescens) is a Pacific Northwest specialty that pushes south into Monterey Bay during the colder months. It is a large, pale gull of Pacific shorelines, and it stands out from most of its relatives on wing color alone. Most gull species have black wingtips, but adult Glaucous-winged Gulls have pearly gray wingtips that match the color of the rest of the back and upperwing.
Structurally, this is a heavyweight among gulls. It has a big, somewhat flat head and a long, heavy bill with a thick tip and pronounced angle along the lower edge, sized between an Iceland Gull and a Glaucous Gull. That bulk places it among the more substantial coastal species discussed in our broader survey of the largest birds in North America, even if it doesn’t top the list.
Range and season matter for spotting this bird correctly. Glaucous-winged Gulls are common year-round on coastlines from Alaska to Washington, but farther south, they should be looked for during winter, and they stay close to shorelines, rarely appearing inland except at landfills. Identification gets trickier because of interbreeding: the species often hybridizes with Western, Glaucous, and Herring Gulls, complicating identification. A useful shortcut from local birders: the Glaucous-winged Gull is lighter gray than the Western Gull, which helps separate the two where their ranges overlap along the bay. Anyone who enjoys sorting through similarly pale-plumaged shorebirds will find comparable identification puzzles in our roundup of water birds in Florida.
6. Bonaparte’s Gull
Bonaparte’s Gull (Chroicocephalus philadelphia) is the smallest and most delicate gull on this list, and it looks almost tern-like next to the bay’s larger residents. It is a small and delicate-looking gull with a thin black bill, and in flight, its flight style and harsh calls resemble terns more than typical gulls.
Breeding plumage makes this species unmistakable, though most Monterey Bay sightings happen outside the breeding season. Breeding adults have black heads, red legs, and large white triangles in the wingtips that contrast with the gray wings, a look shared by several other striking species featured in our guide to birds with black heads. Nonbreeding birds are mostly white with grayish upperwings, white primaries edged in black, and a gray spot on the cheek, the plumage most bay visitors actually encounter.
Timing is everything with this species locally. Bonaparte’s Gull is common from late fall through spring, with large numbers of migrants evident during late fall and again from April to May, though it is only locally numerous in winter and small numbers linger through summer at a few coastal sites. Look for it offshore and along the coast, especially at creek and river mouths, and inland at lakes, wetlands, agricultural fields, and sewage ponds. Among the region’s regularly occurring gulls, it also matures the fastest: a “2 year” gull is the Bonaparte’s Gull, while “3 year” gulls include Heermann’s, Ring-billed, and Mew, and “4 year” gulls include California, Herring, Western, and Glaucous-winged.
| Species | Relative Size | Bill Color | Best Season Around Monterey Bay |
|---|---|---|---|
| Western Gull | Large | Yellow with red spot | Year-round resident |
| California Gull | Medium | Yellow with black ring and red spot | Spring through fall, breeding locally |
| Heermann’s Gull | Medium | Red with black tip | Summer through early winter |
| Ring-billed Gull | Medium-small | Yellow with black band | Winter |
| Glaucous-winged Gull | Large | Yellow, heavy bill | Winter |
| Bonaparte’s Gull | Small | Thin black | Late fall through spring |
Important Note: There are technically no “seagulls” in scientific terminology, but the term remains common shorthand for any gull seen near the coast. Using species names instead sharpens both identification skills and conservation awareness.
Sorting out gulls in Monterey Bay takes practice, but the payoff is real: once the six species above become familiar, the bay’s wharves, beaches, and harbor mouths start to look far busier than a single generic “seagull” would suggest. Bring binoculars, check bill and leg color first, and let the season help narrow down the possibilities before worrying about subtler plumage details.