What kinds of gulls can you find in Delaware?
If you’re like me, you’ll be surprised to find out that there is no specific bird called a “seagull!” Instead, gulls are a diverse family of birds with different habitats, ranges, and color patterns.
I’ve also included terns in the list below, a closely related subgroup of gulls. In general, gulls have hooked beaks while terns’ beaks are straight, and terns have webbed feet while gulls don’t.
Please be aware that today I’m ONLY listing and focusing on the plumage of ADULT gulls. Baby and young gulls’ can look so different that it would be confusing to describe all the variations here. But if you want to dive even deeper into gull identification, check out this field guide, which has photo examples of gulls with different plumage based on their age:
Here are the 14 COMMON Gulls and Terns Found In Delaware!
#1. Lesser Black-backed Gull
- Larus fuscus
- Adults measure 20.5 to 25.2 inches in length and have a 53.2 to 59.1-inch wingspan.
- Breeding adult plumage is white below, slate gray above, white head, black wingtips, and in non-breeding plumage, the head and neck are typically spotted brown.
- They have yellow eyes, bright yellow legs, and a yellow bill with a red spot on the lower mandible.
Although they’re native to Europe, Lesser Black-backed Gulls populations are increasing worldwide. They occupy rocky islands, cliffs, and salt marshes. In addition, you can spot these gulls in aquatic habitats such as bays, lakes, rivers, and the open ocean during the winter and migration season.
Lesser Black-backed Gulls adjust their hunting style depending on the prey. They may swoop down to the water’s surface in flight to catch fish, mollusks, insects, crustaceans, marine worms, smaller birds, and eggs, or forage on land for rodents, berries, seaweed, and seed. They’re scavengers and are often seen around fishing boats and landfills. They will even steal food from other birds.
In spring, Lesser Black-backed Gulls return to breeding grounds soon after the ice and snow have melted. You’re likely to see monogamous breeding pairs preening each other’s head and neck feathers. In North America, Lesser Black-backed Gulls sometimes pair with Herring Gulls due to a lack of available mates.
Both the males and females incubate the eggs and aggressively defend their nest. Their protective behavior continues when their chicks hatch. Males will strike imposing postures and call loudly to warn away other males. They may also get into fights with any bird (or human!) that gets too close. Watch below!
#2. Herring Gull
- Larus argentatus
- Adults range from 22.1 to 26.0 inches in length and have a 53.9 to 57.5-inch wingspan.
- Breeding adults have light gray backs, white heads, white undersides, and black wingtips and may have dusky marks on their heads during the winter.
- They have yellow eyes, dull pink legs, hefty bills, and barrel chests.
Herring Gulls are the familiar, quintessential “sea-gull” in Delaware. They occupy farmland, coasts, bays, beaches, lakes, piers, and landfills. They’re most abundant on the coast and surrounding large lakes and river systems.
If you spend time at the beach, you’ve probably noticed Herring Gulls waiting for you to drop your snack! In addition to popcorn and chips from humans, they consume fish, crustaceans, mollusks, sea urchins, marine worms, smaller birds, eggs, carrion, and insects.
Herring Gulls will stop at nothing to get a meal! They’ve been observed preying on fish driven to the surface by feeding whales. They also will take hard-shelled items such as crabs and mollusks high into the air and drop them onto rocks to break them open.
Individuals have even been observed “fishing.“ One individual was recorded dropping pieces of bread into a pond and catching the goldfish that came up to feed. It didn’t eat any bread itself, suggesting the gull was using the bread as a lure!
The population of Herring Gulls declined steeply during the 19th century because of over-hunting. While their range and population recovered during the 20th century, overfishing, oil spills, and pesticide contamination have reduced some populations.
#3. Ring-Billed Gull
- Larus delawarensis
- Adults range from 16.9 to 21.3 inches in length and have a wingspan of 41.3 and 46.1 inches.
- Breeding adults are clean gray above with a white head, white body, white tail, and black wingtips spotted with white.
- They have yellow legs, eyes, and bill with a black band.
Look for Ring-Billed Gulls in Delaware near aquatic habitats.
These are the gulls you’re most likely to see in inland locations. Look for them on coasts, piers, large bodies of water, and landfills, since they prefer to nest near freshwater sources. These gulls are adapted to human-disturbed areas and are common around cities, farmlands, docks, and even in parking lots.
Ring-billed Gulls are known for dropping and then re-catching prey. This “game” is a way of honing their hunting skills!
Interestingly, Ring-billed Gulls use a sort of built-in compass to navigate. Scientists found that chicks as young as two days old showed a preference for magnetic bearings that would lead them to their winter habitat. They typically return to their nesting location to breed each year, often within a few meters of old nest sites.
#4. Great Black-backed Gull
- Larus marinus
- Adults range from 27.9 to 31.1 inches in length and have a 57.5 to 63-inch wingspan.
- Breeding adults are white with slate-black upper wings and backs.
- They have dull pink legs, darkish eyes, and a large yellow bill with a red spot near the tip.
Great Black-backed Gulls are the largest gulls in Delaware!
They’re mainly found on the coast but sometimes live on large lakes and estuaries. They’re more likely to move inland to large lakes and river systems in the winter. They can also be spotted resting in parking lots, fields, runways, and piers.
These gulls consume various prey. They will feed on fish, marine invertebrates, and smaller birds and eggs along shorelines. They’re known to steal food from other birds and animals, including sharks. That’s a dangerous way to score dinner!
Great Black-backed Gulls are still common in their range, even though overhunting threatened their population in the 19th century. Incredibly, the oldest recorded individual living in the wild was over 26 years old.
#5. Laughing Gull
- Leucophaeus atricilla
- Adults range from 15.3 to 18.1 inches in length and have a 36.2 to 47.2-inch wingspan.
- Adults are medium gray above and white below with reddish-black legs.
- Summer adults have a crisp black hood, white arcs around the eyes, and reddish bills, and in winter, the hood becomes a blurry gray mask on a white head.
Laughing Gulls in Delaware are typically spotted in coastal areas like beaches, salt marshes, and mangroves.
Like many other gulls, Laughing Gulls are adept at foraging while walking, wading, swimming, or flying. Their food sources include crustaceans, insects, squid, human refuse, berries, fish, earthworms, snails, and the eggs of horseshoe crabs.
These gulls steal food from Brown Pelicans by landing on their heads and taking fish from their bill pouch. I’m sure the Brown Pelicans aren’t laughing when that happens!
- RELATED: 26 Water Birds That Live in Delaware! (w/Pics)
They form massive colonies of up to 25,000 pairs during the breeding season. The colonies include terns, larger gulls, Black Skimmers, and American Oyster Catchers. Laughing Gulls are monogamous, and pairs typically stay together for multiple seasons.
#6. Bonaparte’s Gull
- Chroicocephalus philadelphia
- Adults measure 11 to 11.8 inches in length and have a wingspan of 35.4 to 39.4 inches.
- Breeding adults have black heads, gray wings, white undersides, and large white triangles on their wingtips.
- They have red legs, small bodies, and slender bills.
This is the smallest species of gull in Delaware!
Look for Bonaparte’s Gulls on ocean bays, lakes, and swamps. They breed and nest where coniferous trees meet the edges of lakes and bogs.
They visit many aquatic habitats during migration and winter, including lakes, rivers, coastal estuaries and lagoons, and the open sea. In addition, they often congregate around sewage treatment ponds, probably due to the increased insect availability in these areas.
Bonaparte’s Gulls are also known for their “conveyer belt” foraging, which they use in some areas. Large numbers of Bonaparte’s will fly upwind above the water’s surface, dipping down to seize prey such as small fish. Then, when they reach the end of the food patch, they fly upward, and the wind carries them back to the beginning.
#7. Black Tern
- Chlidonias niger
- Adults range from 9.1 to 14.2 inches in length and have a 22.4 to 23.6-inch wingspan.
- Breeding adults are dark gray above with black heads, black undersides, and pale underwings.
- They have dark legs, eyes, and bills.
Black Terns prefer wetlands with extensive vegetation and open water for breeding. They can be spotted in various wetland habitats during migration, including lagoons, river edges, lakes, marshes, sewage lagoons, beaches, and open ocean waters.
They spend their winters in coastal regions of the tropics foraging for small fish in coastal waters. However, they’ll also spend time in lagoons, saltpans, estuaries, shrimp farms, marshes, and farm fields not far from the coast.
Black Terns generally hunt their prey in flight. But, unlike many gulls and terns in Delaware, Black Terns don’t plunge into the water after prey. Instead, they fly low over marsh vegetation and water, swooping low to scoop up prey. They’re agile flyers and will also capture insects out of the air, chasing after them like a swallow.
Black Tern populations have been declining since 1966. Populations frequently move and are difficult to monitor, and the causes of their decline aren’t well understood. However, it’s likely that destruction of wetland habitat, pesticide pollution, and climate change have all contributed.
#8. Common Tern
- Sterna hirundo
- Adults range from 12.2 to 15 inches in length and have a 29.5 to 31.5-inch wingspan.
- Breeding adults are gray overall, but their underside may be lighter. A black cap extends to the back of the neck.
- They have orange legs, an orange bill tipped in black, and dark wingtips.
Common Terns are primarily found in aquatic habitats in Delaware, including the ocean, lakes, bays, and beaches.
These terns primarily feed by flying over the water, hovering, and plunging in to catch prey below the surface. However, they will also catch insects in the air and steal food from other terns.
Common Terns engage in courtship displays in the air and on the ground. In the air, the male crouches while the female flies over him then they descend to the ground in a zigzag pattern. On the ground, the male walks around the female with his head down and his wings out and down.
Together the pair will aggressively defend their territory from intruders. First, they will try to ward off intruders by posturing with their heads down and their wings out and down. If this fails, they’ll attack intruders, wresting and fencing with their bills. If humans enter the colony, they will dive toward them, peck their heads, and defecate on them.
#9. Forster’s Tern
- Sterna forsteri
- Adults measure from 13 to 14.2 inches in length and have 30.7 to 31.5-inch wingspan.
- Breeding adults are gray above and white below with a black cap.
- They have an orange bill with a black tip, orange legs, and silvery wingtips.
The Forster’s Tern is the most widespread tern in Delaware!
Forster’s Terns spend the breeding season in marshes and wetlands. They winter along the coast and can be spotted in estuaries, inlets, coastal lagoons, and sheltered bays.
Forster’s Terns typically fly along or near shorelines 20 to 25 feet in the air and feed on small fish. They catch prey by diving and plunging into the water, occasionally from as high as 50 feet up. These birds normally make shallow dives but can take prey nearly a foot below the water’s surface.
The populations of Forster’s Tern are difficult to monitor because their colonies shift locations from year to year. However, they’re believed to be stable. Sea-level rise and destruction of wetland habitats may become issues in the future for this species.
#10. Royal Tern
- Thalasseus maximus
- Adults range from 17.7 to 19.7 inches in length and have a 39.4 to 43.3-inch wingspan.
- Breeding adults are gray below and white above.
- They have a black crest and bright orange bill.
Royal Terns spend their lives in warm coastal waters. They’re frequently spotted in sheltered areas with shallow water, such as estuaries, bays, lagoons, and sandy beaches. They occasionally travel out to sea or inland, especially when feeding young, but stay within 50 miles of the coast.
Breeding pairs of Royal Terns choose a site and build their nests together. The nests are simple scrapes in the earth. But, they have an unusual way of strengthening their nests. They defecate around the rim of the nest, and as it hardens, it reinforces the nest rim and helps keep it from flooding.
Royal Terns can recognize each other by voice, which helps parents only provide food to their own chicks. Large breeding flocks find this useful so that parents don’t get nests mixed up!
Unlike most terns in Delaware, the young remain with their parents, and the family travels southward as a group.
#11. Least Tern
- Sternula antillarum
- Adults range from 8.3 to 9.1 inches in length and have a wingspan of 18.9 to 20.9 inches.
- Breeding adults are pale gray and white.
- They have a black cap, white forehead, and yellow bill.
This species is the smallest tern in Delaware and the world!
Look for Least Terns in various aquatic habitats, including bays, estuaries, and reservoirs. Least Terns winter on South American coastlines, often in bays or estuaries near river mouths.
Both parents defend the nest and a small area around it. They will call loudly and launch attack flights against trespassers. In addition, they may dive-bomb anyone that approaches their nest. This behavior has earned them the nickname “little strikers.”
Least Tern populations have declined severely in the last half-century. Nesting colonies compete with humans for space on sandy beaches. Unfortunately, they are also highly susceptible to oil spills and other pollutants.
#12. Caspian Tern
- Hydroprogne caspia
- Adults range from 18.5 to 21.3 inches in length and have a 49.6 to 50.4-inch wingspan.
- Breeding adults are white overall with pale gray upper wings and a black crown, and from below, the outer primary wing feathers are dark gray.
- They have black legs and a coral-red bill with a dusky tip.
Caspian Terns rarely travel far out to sea.
They occupy various aquatic habitats, from coasts and barrier islands to interior rivers and lakes.
Caspian Terns hunt by flying over the water and diving after prey they spot, often plunging several feet below the surface. They will also occasionally chase other birds and steal their food.
Male Caspian Terns use an age-old strategy to attract a mate – he gives the female a present! He will catch a fish and present it to a female while nodding. Receptive females accept the fish and sometimes hunch down, jerk their head up and down, and call like a chick begging for food. Watch below!
Caspian Tern populations are believed to be stable overall though they are difficult to monitor because many colonies nest in remote areas. Several U.S. states and Canada list them as threatened, vulnerable, or endangered. Pesticides, hunting, colony disturbance, and loss of nesting areas all contribute to the decline of this tern.
#13. Northern Fulmar
- Fulmarus glacialis
- Adults range from 15.3 to 19.7 inches in length and have a 39.4 to 44.1-inch wingspan.
- Most fulmars are “light morph” and gray above and white below; some “dark morphs” are pale to dark gray.
- They have a thick bill and bluish legs.
Unlike most other terns in Delaware, Northern Fulmars spend the majority of their lives on the open ocean and are rarely seen from land. They breed and nest in colonies on sea cliffs, generally over cold water, in hard to reach areas.
Northern Fulmars will feed during the day or night, catching much of their prey by seizing items on or just below the surface while swimming. However, they may also dive into the water from the air going as deep as 12 feet!
They often follow whaling vessels and scoop up garbage, offal, and bycatch. Northern Fulmars eat squid, crustaceans, jellyfish, octopuses, bristle worms, carcasses of dead marine animals, and fish.
Both chicks and adults can defend against predators by spraying foul-smelling oil from their mouths for several yards. Their stomach produces the oil, which mats the feathers of avian predators, limiting their flight.
#14. Black-legged Kittiwake
- Rissa tridactyla
- Adults range from 15 to 16.1 inches in length and have a wingspan of about 37 inches.
- Breeding adults are pale gray above and white below with neat black wingtips.
- They have yellow bills and jet-black legs.
Black-legged Kittiwakes spend most of their time at sea. They forage primarily in cold water and nest in large colonies on seaside cliffs to avoid predators. Occasionally, they nest on buildings and shipwrecks.
They do most of their foraging in flight. They dip down and skim the surface or plunge into the water after prey, diving up to three feet. These birds also steal prey from other kittiwakes! Black-legged Kittiwakes primarily feed on small fish, squid, marine worms, zooplankton, and jellyfish.
During the spring bonding period, pairs will greet each other with nodding, head-bobbing, and crossed necks. It often looks like humans saying hello after an extended time apart!
Males defend their nest sites vigorously. They use a protective posture that includes extending their neck and rising off the ground, then facing their opponent with an open bill. They may also fight, grabbing another kittiwake’s bill and twisting their opponent’s head.
Black-legged Kittiwakes are a species of low conservation concern in North America. However, some countries have seen rapid declines, which are believed to be related to warming sea temperatures that have reduced plankton populations.
Which of these gulls and terns in Delaware have you seen before?
Tell us below in the COMMENTS section!