Herring gulls prefer to drink fresh water, but in the absence of fresh water will drink sea water. These birds have glands located over their eyes which excrete salt; this excretion can be seen dripping off herring gull bills.
Herring gulls are part of a complex of gulls in the Northern Hemisphere, with species and subspecies classifications changing over time. Thayer’s gulls (Larus thayeri) were at one time considered a subspecies of Larus argentatus or Iceland gulls (Larus glaucoides). The only currently recognized subspecies that breeds in North America is L. a. smithsonianus, while nine subspecies are recognized in Eurasia. In addition to subspecies, hybrids are known to occur with great black-backed gulls (Larus marinus) in Canada and with glaucous-winged gulls (Larus glaucescens) in Alaska and Utah.
Herring gulls have no song, but have a complex system of anywhere from 8 to perhaps 15 calls; two are used by nestlings and another three are used only by breeding adults. Various calls serve to identify returning partners, demonstrate aggression, warn the colony of predators, and to dispute territory with neighboring gulls. When males are disputing territory, they may pull at grass with their beaks as part of their demonstration. Chicks begin making begging calls to demand food upon hatching; the call grows more intense as they grow and by 5 weeks of age, a chick begs by lifting its head with each peep and holding its head hunched against its body. When chicks are pursued, they emit a shrill waver. The begging call and shrill waver exhibited by chicks are both similar to noises that adult gulls make. Chicks also peck at the red spot on their parent's bills in order to stimulate food regurgitation.
Communication Channels: visual ; acoustic
Other Communication Modes: duets
Perception Channels: visual ; tactile ; acoustic ; chemical
Herring gull populations seem to be stable and are not recognized as at risk by conservation agencies.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Herring gulls have an adverse effect on humans in areas where their population size, combined with their foraging habits (e.g., stealing human food), makes them a pest.
Gulls, including Larus argentatus, are involved in approximately 20.3% of collisions between aircraft and birds. Collisions between aircraft and birds have caused 159,504 hours of aircraft downtime in a 13-year period in the United States and result in economic losses of hundreds of millions of dollars annually.
Herring gulls are significant enough in population size to permit their use as experimental subjects both within the wild and the laboratory, with potentially positive results for humans gleaned from the research. In addition, the wide geographic range of herring gulls makes the species useful for making observations concerning pollutants for a great number of areas. For example, herring gulls in the wild have been used to study the behavioral effects of lead, and herring gull eggs from large parts of North America have been used to analyze levels and spread of a number of chemical contaminants.
Herring gulls can contribute to beach sanitation by eating dead fish and trash left behind by humans. The gulls, in the pursuit of food, also sometimes lead fishermen to schools of herring. A study in Murmansk, Russia, found that because the diet of urban herring gulls consisted of about 45% rat and town animal remains, herring gulls may contribute to urban sanitation.
During the late 19th century, along the Atlantic coast, herring gulls were a useful source of eggs and were also pursued for the decorative value of their feathers.
Positive Impacts: food ; body parts are source of valuable material; research and education
Though Larus argentatus is a predator of other birds, its attacks on predators sometimes serve to protect birds such as eiders (Somateria mollissima) and puffins (Fratercula artica) which live nearby. Herring gull consumption of dead animals on land and at sea is a form of biodegradation.
Ecosystem Impact: biodegradation
Herring gulls are opportunistic predators of marine invertebrates, fishes, insects, other seabirds, other birds, bird eggs, and are opportunistic scavengers of dead animals and garbage. Herring gulls are omnivorous but prefer animal foods. Herring gulls at sea forage in scattered groups that converge quickly once prey has been located; the birds follow foraging whales or even fishing boat nets, eating fish, squid, and zooplankton at the surface. Individual specialization in feeding is common, i.e., a particular bird will seek out the same type of food again and again. The type of food consumed differs by the given bird's location and the time of year. For example, in Newfoundland, herring gulls often eat mussels (Mytilus edulis) and refuse during incubation, switch to capelin (Mallotus villosus) when chicks hatch, and then switch to squid (Illex illecebrosus) later in the summer. Herring gulls appear to choose foods according to their dietary needs (such as during egg-laying) when sufficiently numerous food sources are available.
Animal Foods: birds; mammals; fish; eggs; carrion ; insects; mollusks; terrestrial worms; aquatic crustaceans; echinoderms; other marine invertebrates; zooplankton
Plant Foods: roots and tubers; seeds, grains, and nuts; fruit
Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Eats non-insect arthropods, Molluscivore ); omnivore
Larus argentatus is found across Eurasia and North America. The herring gull geographic range stretches across the northern hemisphere through Alaska, northern Canada, and Russia. Herring gulls are found on both North American coasts, having gradually extended in range down the Atlantic coast. They can be found year-round in the lower Great Lakes area, but generally breed in the northern area of their range and winter in the south along the Pacific and Atlantic coasts, the Gulf of Mexico, and on several Caribbean Islands.
Biogeographic Regions: nearctic (Native ); palearctic (Native )
Other Geographic Terms: holarctic
Herring gulls tend to live and breed in coastal areas and generally only live inland in small numbers and near bodies of water. The most important habitat requirements are the nearby presence of a food source, distance from major predators, and shelter from prevailing winds. Herring gulls prefer to breed on flat ground on offshore islands, on the mainland these gulls prefer cliffs, where there is less risk of exposure to predatory mammals. Although herring gulls prefer to nest on rock or sand, highest breeding success has often been observed in birds that nest in vegetated areas. Herring gull foraging habitat is not typically the same as their nesting habitat; in coastal areas herring gulls search for food in the intertidal zone and at sea. Herring gulls are also found in coastal urban areas, nesting on roofs and eating urban refuse.
Habitat Regions: temperate ; terrestrial ; saltwater or marine
Aquatic Biomes: lakes and ponds; coastal
Other Habitat Features: urban
Herring gulls live up to 30 years of age, but many die earlier, especially as chicks. Causes of mortality include injuries, being shot or poisoned by fishermen, ingesting contaminants such as bacteria and lead (especially in the Great Lakes, where many chicks have shown deformities related to toxins), fishing lines and nets, and occasional predation by predators such as owls and foxes. The dangers presented to Larus argentatus in the Great Lakes by contaminants have decreased since the 1980s, when contaminant levels began to decline. Most deaths occur during breeding, when both adults and young are vulnerable.
Range lifespan
Status: wild: 31 (high) years.
Herring gulls are fairly large gulls. Male herring gulls range in size from 60 to 66 centimeters in length and 1050 and 1250 grams in weight, while female herring gulls range from 56 to 62 centimeters in length and 800 to 980 grams in weight. The wing span of herring gulls ranges from 137 to 146 centimeters. While male herring gulls are larger than female herring gulls, the sexes have similar plumage. Their heads and underparts are white, and they have light gray backs. Herring gulls have yellow bills with a red spot on the lower mandible and pink or flesh-colored legs. Herring gull outermost wing feathers are black and have a white spot. During winters, adult gulls have streaks of brown coloring on their heads. Adult herring gulls have golden eyes surrounded by a yellow-orange ring of skin.
Herring gulls take four years to acquire standard adult plumage and are mottled brown during their first four years. The eyes of immature herring gulls are dark brown, rather than golden, and are surrounded by blackish skin, rather than orange-yellow. Their bills are black and their legs are dark gray.
Herring gulls belong to a complex of gulls, all of which share similarities and may be confused with one another. Because of hybridization and other factors, the taxonomy of gulls is complicated. Great black-backed gulls (Larus marinus), are much larger than herring gulls and have a lighter bill and darker mantle. Lesser black-backed gulls (Larus fuscus) have a dark mantle and yellow legs. Both great and lesser black-backed gulls have occasionally hybridized with herring gulls. Ring-billed gulls (Larus delawarensis) are smaller than herring gulls, with yellow legs in adulthood and possessing a bill with a distinct black ring and lacking a red spot. Thayer's gulls (Larus thayeri) are quite similar to herring gulls, but adult Thayer's gulls have dark eyes and much less black coloring under the wingtip. The species status of Thayer's gulls has been questioned. They may be a form of Larus argentatus or Iceland gulls (Larus glaucoides). California gulls (Larus californicus) have yellowish green legs, a black spot in front of the red spot on the bill, and are smaller than herring gulls. Western gulls (Larus occidentalis) are similar in size but have a darker mantle. Glaucous-winged gulls (Larus glaucescens) are similar in color but somewhat larger in size compared to herring gulls, and have pale gray rather than black wingtips in addition to a dark iris and purplish skin around their eyes. Hybrids between western gulls and glaucous-winged gulls can appear quite like herring gulls, but often with less black wingtips. Mew gulls (Larus canus) are much smaller than herring gulls and have yellow legs and unmarked yellow bills.
Range mass: 800 to 1250 g.
Range length: 56 to 66 cm.
Range wingspan: 137 to 146 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
The preference of jerring gulls for living on cliff edges and on rocky off-shore islands with available hiding spots for chicks reflects anti-predator behavior. When a predator is first seen, herring gulls give an alarm call. If a predator approaches, herring gulls give a warning call and then take flight. Herring gulls mob flying predators by diving and striking with beaks and feet, and also dive at terrestrial predators, striking then with wings and feet, rather than with beaks. If a chick gives a shrill waver, its parents attack the involved predator while other herring gulls make intense calls described as "long-call notes."
Known Predators:
Herring gulls are almost always monogamous, with rare cases of 1 male and 2 females occupying a territory and incubating 1 or 2 nests. The secondary female rarely achieves breeding success. Pairs are formed on the male's territory or in loafing areas. Males and females choose territory for egg-laying together, once they have paired. Males regurgitate food for females before eggs are laid. Any late arrivals pair only after early-nesting pairs have already begun breeding. Pair bonds are maintained for the life of both partners. If a male fails to provide enough food to the female during egg formation or if the partners fail to synchronize their eggs (leaving eggs unattended and often lost or eaten), the pair may separate. Within the colony, pairs nest as far apart as space allows.
There are no displays specific to courtship, but females usually approach males in a hunched posture, producing a begging call. The male responds by assuming an upright posture or mew-calling (see Pierotti & Good for more information on specific types of calls). Head-tossing occurs repeatedly by both male and female and the male regurgitates food for the female; if she eats it, copulation often happens immediately. Otherwise, the female may walk away and prevent copulation. Males jump on females' backs with wings outspread in order to copulate. Mate-guarding is most intense in the week prior to egg laying. Males whose mates have already laid eggs may attempt to force copulation on neighboring incubating females; no such attempt has ever been observed as successful.
Mating System: monogamous ; polygynous
Herring gulls breed during spring, pairing around mid-March and laying eggs by mid-May. Adults breed beginning around four years of age, although breeding for the first time at three or five years of age is also observed. Females take 4 to 6 days to lay 3-egg clutches, and the eggs are incubated by both parents for about four weeks. Chicks are able to leave the nest on foot after just one day. Chicks fledge after about six weeks and are fed in the territory where they were born for until about 12 to 15 weeks old. Occasionally, they are cared for by parents off territory for as long as 6 months.
Breeding interval: Herring gulls breed once yearly.
Breeding season: Herring gulls breed from April to June, including nesting and copulation.
Range eggs per season: 1 to 3.
Average eggs per season: 3.
Average time to hatching: 30 days.
Average fledging age: 6 weeks.
Range time to independence: 24 (high) weeks.
Average time to independence: 12 to 15 weeks.
Average age at sexual or reproductive maturity (female): 4 years.
Average age at sexual or reproductive maturity (male): 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Both male and female parents incubate eggs. The female spends more time incubating than the male does, and incubates at night. The male spends more time away from the nest, procuring food for the female. Many parents remove broken shells once chicks have hatched. Chicks are semiprecocial at hatching, with gray and black down and open eyes. After one week they are able to run around on their own. Chicks are protected by both parents and, during dangerous weather, are brooded until 10 days of age. Chicks fledge at about 6 weeks of age and are fed by parents on parental territory until they are 11 to 12 weeks old; so long as chicks continue to beg, they may receive food from parents until about 6 months of age. Males feed more often before fledging, females feed chicks more after fledging. Studies have found that herring gull parents can feed lead-poisoned chicks, which are generally lighter than normal chicks when studied in the laboratory, enough so that the chicks maintain a close-to-average weight (Burger and Gochfeld, 2000). Chicks are fed regurgitated food that consists of small prey such as small fishes, insects, and earthworms.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)
