Seagull Nesting Secrets: Unveiling the Hidden Sanctuaries by the Sea

Whether scavenging for french fries or foraging for fish and invertebrates, Seagulls are ubiquitous birds of the coast and many inland waterways. They may be unpopular with some people, but Gulls perform an important function as predators and scavengers.

Some of the over 50 Gull species have become very common around towns and cities where abundant food sources and safe nesting sites are available. As abundant as these birds are, few people will have seen their nests or observed their interesting breeding behaviors.

In this guide, we’ll cover everything about Seagull nesting. Read along with us to learn everything from where they build their nests to how they care for the chicks.

A colony of nesting seagulls

Choosing the Perfect Site

Safety is a Gull’s first concern when choosing a nest site, which is reflected in their choice to nest in inaccessible places like cliffs and islands. Most species are ground-nesters, although Bonaparte’s Gull (Chroicocephalus philadelphia) has the unique habit of nesting in trees.

Suitable sites may be in short supply, so many species will nest in colonies, often very close together and sometimes mixed with other bird species. Access to food resources for their growing chicks is also a priority, of course, so Gulls tend to nest in coastal or urban areas with healthy fish stocks or near dumps and other foraging sites.

In some parts of the world, Gulls have learned to nest on artificial structures like bridges and buildings. These are similar in structure to their natural cliff habitats and provide a high degree of safety from hungry predators.

Site selection is crucial, and species like the Laughing Gull (Larus atricilla) may spend several weeks at a potential site before beginning nest construction. Once a good spot has been secured, Gull pairs will often return to nest in the same area or even territory in successive years.

Seagulls mainly build their nests in hard to reach places, such as cliffs and islands

Time of Year

Gulls typically nest in the spring and summer, between March and September in the northern hemisphere. However, their timing varies depending on their species and locality.

Southern nesters can begin earlier as they do not need to wait for snow to melt before laying their eggs.

In Alaska, for example, Gulls lay their eggs from around mid-May, while in the Gulf of California, egg laying may begin as early as mid-March.

Seagull sitting on their nest

Nest Construction

The nest is built by both males and females with materials collected and carried with their bills. They often build their nest up against some form of shelter, like a rock or shrub, to shield it from prevailing winds.

Gulls are not particularly accomplished nest builders, and many species simply dig a shallow scrape in the sand or soil and line it with some plant material, pebbles, seashells, and feathers. These birds will also use all sorts of artificial materials, including bits of rope and plastic.

However, not all Gulls build their nests on the ground. Kittiwakes (Rissa tridactyla) nest on narrow cliff ledges, building a small mound of mud and vegetation. Meanwhile, Franklin’s Gull (Leucophaeus pipixcan), an inland species from North America, builds a nest of floating vegetation on shallow freshwater wetlands.

Gull nests are generally rounded and vary in form from tall mounds to typical cup or saucer shapes. They range in diameter from a little over 7 inches in the Little Gull (Hydrocoloeus minutus) to over 1½ feet in the largest species. Pairs may reuse old nests, which can become pretty large as new material is added.

A group of seagulls nesting inland, on the top of a roof

Breeding and Mating

Gulls form monogamous pairs, and some may mate for life. Romance begins in early spring when pairs form or reunite upon arrival at the breeding grounds.

They will court each other and complete the balancing act of mating several times in the week or two before the female lays her eggs. Courtship includes various calls and bond-strengthening behaviors like mutual feeding.

Eggs

Gulls lay a single clutch of well-camouflaged, speckled eggs that blend in with their nest. They typically lay 1 to 5 (Usually 2 - 3) relatively large eggs, ranging in size from about 1.5 inches (40mm) and 20g in small species like the Little Gull to 3 inches (77mm) and 117 g in the Great Black-backed Gull (Larus marinus). For reference, a medium chicken egg weighs 1.75 oz (50 g) in the US.

The nest of a seagull, with three eggs inside

The Life Cycle of the Young

Gulls are long-lived birds, and they don’t start their lives in a hurry. The timeline from hatching to independence may take several months, depending on their species.

Most Gull eggs hatch after three to five weeks of incubation by both parents. The semi-precocial young can see and walk on their first day and often leave the nest soon after hatching. However, they don’t go far, remaining near the nest for their first two to three weeks. Like the shell they hatched from, Gull chicks are cryptically camouflaged in gray-brown and black speckles.

Gull chicks are brooded for their first few days and require regular meals for several weeks before becoming independent. The young birds may take many years to reach sexual maturity and develop their adult plumage. Larger species, like the Great Black-backed Gull, may breed for the first time at the age of four or five years, which is around the total life expectancy of many smaller bird species.

Black-billed Gull with two chicks in the nest

Parental Care

Gulls are monogamous, and both males and females work together to forage and feed their young. The chicks are fed by regurgitation, and fledging typically occurs after about six weeks, depending on their species. Even after fledging, the chicks of some species may remain near their parents and beg for food for up to six months as they learn to forage for themselves.

Despite choosing their nest site carefully, predators are a constant risk, and parents rarely leave young chicks unattended. However, Gulls are not afraid to defend their nests, and the colony may act collectively to drive off a potential predator.

Gulls are opportunistic predators and scavengers by nature, so other Gulls pose a significant risk. To minimize their losses, these birds set up carefully defended territories, ranging from a few feet to a few yards in diameter. Pairs defend their territories aggressively using calls, displays, and physical conflict if necessary.

Adult gull with two young chicks by its side

Challenges and Threats

Nesting is a dangerous time for all bird species, including Gulls. These birds nest in very exposed areas, so extreme weather events and predation are a constant threat. Many mammalian predators will feast on Gull eggs and chicks, including species like foxes, mink, and weasels.

Nesting in inaccessible sites can reduce the risk of these ground predators, but many birds also feed on Gull eggs and chicks. Potential predator species include Ravens, Crows, Great-horned Owls, and other Gulls.

Gull species are generally adaptable and opportunistic birds, although many are in decline due to various factors like pollution, overfishing, and climate change. According to the IUCN Red List, there are six vulnerable species and four in the near-threatened category.

Interesting Seagull Nesting Facts and Observations

• Many Gulls have a red spot on their bills. This ‘target’ is an important visual cue that encourages chicks to beg from their parents.
• Gulls will gather in large numbers in the air above potential predators at the colony, even if they are far from their own nest.
• Gulls often feed on the eggs and young of other birds and even other gulls. Some Gulls in the colony even cannibalize the young of their own species.

Close up of a seagull sat on a nest

Summary

From floating nests to complex territorial communication in tight-packed colonies, Gulls display some fascinating breeding and nesting behaviors.

Whether at a remote and rugged coastal seabird colony or a downtown rooftop, observing Gull nesting behavior can be a wonderful experience. Just remember to stay well back - these birds are not afraid to defend their nests!

It is a shame that many people see seagulls as nuisance animals, but hopefully, we can continue to adapt and learn to live alongside wildlife in our ever-changing world.

Seagulls tend to nest in colonies - Kenai Fjords, USA

FAQs

How long is the incubation period for Seagulls?

Depending on their species, Seagull eggs usually hatch after three to five weeks. Both parents develop brood patches for transferring body heat and take turns incubating the eggs.

What is the survival rate for young Seagulls?

Gulls have a surprisingly long lifespan, with many living to 20 years and some even approaching 50! Adults have few predators and a very high survival rate, particularly in urban areas. However, reaching adulthood is filled with danger, and only about half of young Herring Gulls survive to fledging age.

How can one observe Seagull nesting without disturbing them?

Binoculars are a birdwatcher's best friend. Approaching any nesting bird causes anxiety for the adults, and in the case of Gulls, it can also cause some surprisingly aggressive responses! It’s best to watch from a distance and keep an eye on the parent birds. You’re a little too close if they start showing signs of agitation.

What can we do to help in the conservation of Seagulls?

Volunteering or donating to conservation organizations and charities are among the best ways to contribute to Gull conservation. However, we can also contribute through everyday choices like avoiding unsustainable seafood products, recycling, and avoiding products with unnecessary plastic packaging.