Today we focus on one of the most common groups of seabirds that can be recognized even past ocean coasts….gulls! Gulls have several common features, and there are numerous species of gulls; some species may look extremely similar. Gulls belong to about 43-45 different species, and are in the family Laridae. This family may or may not include others (e.g. terns and skimmers), based on differing scientific classifications. Many of us refer to gulls as “seagulls”; they are usually synonymous with visiting the beach or oceanside! To learn more about gulls, read on below!
Although familiar around ocean coasts, birds of Laridae are also associated with other water bodies. Different gull species may be difficult for the average passerby to differentiate. Gulls are strong medium sized or large birds, slim or stout and have varying color patterns of white, grey and black. A ring of color around the eyes and the colors on their legs and bills assist with species identification. Gulls also have webbed feet. Their bill may be slightly hooked and can be sharp or blunt.
Gull plumage can vary dramatically; age of the animal, breeding season and species (including being a hybrid species) will all play a role in the plumage. Sizes of gulls and wingspans also vary between the numerous species; wingspans may range from 24-60 inches across. Their long wings are usually pointed at the tips and they do have tails, which may vary in shape.
There are members of the family Laridae on every continent, making it an extremely well-distributed group. About 16 different species of gulls have been seen nesting in Canada. There are about 28 species which can be seen in North America and the entire Northern Hemisphere sees about 30 species which includes Arctic regions. Some examples of gulls seen in North America include Larus glaucescens, the Glaucous-winged gull (very common on the West Coast) and Larus argentatus, the Herring Gull. As mentioned above, family Laridae has a strong association with water bodies, and many species are coastal.
Gull habitats are highly variable as they are extremely adaptable; they may live from Arctic to tropical seas, along freshwater shores (e.g. rivers and lakes), in forests, meadows, cliffs, islands, buildings, marshes and deserts, on farms or near other human-influenced areas such as landfills.
Gulls consume a wide variety of prey as generalist, opportunistic feeders. They will seek out rodents (e.g. moles, rabbits), reptiles, amphibians, mollusks, insects, dead or live fish (e.g. herring), crustaceans, berries, seeds, humans’ crops, worms, garbage and even other young birds and eggs. They may also steal or find human food, or prey caught/left by other birds. An interesting hunting technique of some gulls is seen when hunting mollusks (e.g. clams). Gulls may fly up with a shelled creature, to then drop the creature onto a hard substrate; this cracks the shells open wide for easy feeding of the soft animal inside. Another technique involves stomping on the ground, mimicking rain, to draw out earthworms. Thus, foraging techniques may vary! Some gulls may also scavenge in tide pools or land near the surface for schools of fish amongst other feeding wildlife (e.g. Humpback whales).
When spotting a large congregation of seabirds, such as gulls, over the surface of the ocean, it is often key that there is food suspended underneath the surface. This is one of the key clues that may suggest a larger marine animal, like a whale, is feeding nearby.
Many seabirds of the family Laridae breed in the Northern Hemisphere, but there are nesters worldwide. They often build ground nests in groups (colonies) near a water source. That being said, nests may also be built on cliffs, in trees, marshes or even on human structures. The Glaucous-winged gull may nest in colonies of up to 10,000 pairs! For the gulls that breed in inland areas, they often end up near coasts during the wintertime. Males and females cooperate when incubating and feeding their young, and may travel 100 miles between their nesting and feeding sites!
The female will lay between 1-4 eggs about once a year (may vary). The mates may reunite from year to year and even produce nests in the same areas. Herring gulls, for example, may use the same sites for 10-20 years. To tell a breeding individual, the head is usually a uniform color of white, grey, black or brown, as opposed to the mottled non-breeding appearance of adults. Juveniles will also take roughly 3-4 years to achieve their adult plumage appearance.
Various Indigenous cultures in Canada have used gulls for different purposes; stories and opinions around the birds also differ. For example, gulls are present on the clan crest of the Nuu-chah-nulth People. Other groups such as the Coast Salish, Red Earth Cree and Hudson Bay and Labrador Inuit Peoples consumed gulls. The Haida People were known to use feathers for pillow stuffings. Other cultures also used feathers for arrow-making, such as the Nuxalk and Nootka Peoples on Vancouver Island. Read more about the diverse uses and perspectives of gulls in Indigenous cultures in Northern North America here.
Gulls often fly on drafts they catch with their outstretched wings, and usually point their bills forwards when flying. Gulls do not often go too far out to sea. They do have natural predators in sharks, eagles, falcons and foxes and some even within their own species (through cannibalism). Eagles and ravens may also steal eggs. There are eight species of gulls in British Columbia- see if you can identify a species the next time you see a gull!
There have been recent artificial population increases seen with some varieties of gulls due to excessive food presence from humans’ garbage. These high population numbers can cause problems with disease transmission to humans, danger to aircraft and depopulation of other seabirds. Thus, there is much care needed to prevent excessive population growth for certain gull species through management of human garbage supplies. Not all populations have increased or are expected to increase, however. For example, the Herring gull is expected to lose habitat in the future due to human impacts, such as the reduction of nesting space.
Gulls are integral and familiar members of many aquatic ecosystems. It is integral to manage gull populations accordingly, to ensure that natural population levels are being maintained of gulls and other seabirds.
To test your knowledge on gulls, try out some trivia below!
- True or False? Gulls may be seen as useful to humans as they clean beaches. (ANS: True. Gulls often feed on leftover garbage and dead fish).
2. Yes or No. Can gulls drink salt water? (ANS: Yes. They have specialized gland structures to deal with the salt).
3. Yes or No. Is the Glaucous-winged gull and the Glaucous gull the same species? (ANS: No. 2 different species).
What do some gulls do in order to take care of their eggs, aside from incubating?
They may evenly turn the eggs every now and then to help with development of embryos.
Article Authored By: Alexa D., B.Sc./ Five Star Whale Watching.
To learn more about gulls and the family Laridae, check out our References below!