The common term “seagull” is a colloquial name that ornithologists do not use, instead referring to these birds as gulls, members of the family Laridae. While their association with the coast is strong, the family’s true distribution extends far beyond the ocean’s edge, challenging the assumption that they are strictly marine birds. Gulls are highly adaptable and opportunistic scavengers, traits that have allowed them to colonize a vast array of environments. This flexibility in diet and habitat selection explains why they are encountered in places one might least expect.
Global Geographic Range
Gulls exhibit a cosmopolitan distribution, meaning they are found on almost every continent across the globe. Species successfully breed from the high Arctic down to the margins of Antarctica, demonstrating tolerance for diverse climates. Their presence spans polar, temperate, and tropical climate zones.
The greatest species diversity, however, is concentrated in the Northern Hemisphere, where approximately 30 species thrive in Arctic and temperate zones. Although they are found globally, gulls are less common in the deep tropics, with exceptions such as the Swallow-tailed Gull, which is endemic to the Galapagos Islands.
Diverse Coastal and Inland Habitats
Coastal Environments
The primary distribution of gulls centers on traditional marine environments, including rocky cliffs, sandy beaches, mudflats in estuaries, and offshore islands used for breeding colonies. These coastal areas provide reliable foraging opportunities, from scavenging washed-up marine life to preying on crustaceans and mollusks. Gulls can drink both fresh and salt water, aided by specialized supraorbital glands that excrete excess salt, allowing them to exploit these transitional habitats effectively.
Inland and Freshwater Systems
Moving inland, many gull species readily utilize extensive freshwater systems, establishing residency hundreds of miles from the ocean. They are commonly seen around large lakes, major river systems, and reservoirs, where they hunt insects, fish, and earthworms in agricultural fields. The Grey Gull, demonstrating adaptability, even breeds in the interior of the Atacama Desert in South America, far from any permanent body of water.
Human-Altered Landscapes
The modern success of gulls is linked to their exploitation of human-altered landscapes, which provide predictable food sources. Urban areas, farmlands, and transportation hubs have become important habitats. Gulls frequently forage in landfills, parking lots, and docks, consuming human refuse and exploiting agricultural waste. Species that naturally nest on cliffs, like the Herring Gull, show behavioral flexibility by substituting coastal cliffs with man-made structures, often nesting successfully on city building roofs.
Seasonal Migration Patterns
The location of gulls is not static, as most species undertake some form of seasonal movement, driven primarily by fluctuations in food availability and the need to reach breeding grounds. Migration distances vary significantly; some gulls are resident, only dispersing locally along coasts, while others are short-distance migrants moving to warmer wintering harbors. Other species are known for long-distance migrations, often covering vast distances between hemispheres.
A notable example of extreme movement is the Sabine’s Gull, which breeds in the Arctic and migrates to wintering grounds off the coasts of western South America and southern Africa, covering annual round trips of up to 40,000 kilometers. Similarly, the Franklin’s Gull breeds in the marshlands of interior North America but flies to the Pacific coast of South America for the winter season. These movements ensure that gulls can consistently access rich feeding areas, whether those are natural fish stocks or human-associated food patches.