Branta leucopsis

Geographic Range

The species consists of four main migrant populations that utilize various wintering and breeding grounds. These main populations number in the tens of thousands with the largest consisting of well over 100,000 individuals. Other smaller populations have been identified but these populations number only in the few thousands. The wintering grounds of all of these populations are located in the British Isles and coastal Netherlands and are separated by relatively short distances, while their breeding grounds are widely separated in the northern European arctic. These four main populations range from their wintering grounds in northern Scotland to their breeding grounds on the east coast of Greenland:

Greenland population : This population consists of about 45,000 individuals. Their breeding grounds are located on the ice-free coasts of East Greenland. These individuals gather mostly on cliff ledges or on small islands that are close to the shores. In September, when the weather conditions in Greenland worsen, they head for their wintering grounds on the shores and islands of northern Scotland. On their way to Scotland, they make a stop at Iceland for about four weeks and then continue their migration.

Svalbard population : This population consists of about 25,000 individuals. They breed on the islands of the Svalbard archipelago and the small islands that surround it. They leave Svalbard in the middle of September and make a stop on the western coast of Norway before continuing on to their wintering grounds in Solway Firth on the west coast of England. This migration path is about 2,500 to 3,000 km in distance.

Russian population : This population consists of over 100,000 individuals. They breed on the north-west coast of arctic Russia. This population initially wintered in Western Germany, however due to increased interruption of wintering areas in Western Germany and the creation of new grazing areas in the coastal regions of Netherlands the entire population has had to shift their wintering grounds to the Netherlands.

Novaya Zemlya population : This population consists of about 10,000 individuals. They breed in the archipelago islands of Novaya Zemlya off the coast of western arctic Russian mainland. They migrate to the coastal regions of Netherlands to spend the winter.

Additionally, it is believed that an ancient population may also have lived on the north-east coast of Canada, however currently there is insufficient data to support this hypothesis.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native

• Other Geographic Terms
• holarctic holarctic

Habitat

The species often occupies pasture land, salt marshes, and grassy fields near the coastal regions of the European arctic and the British Isles. Although conservation efforts have allowed the generation of designated areas from which the species can benefit, they have been known to graze in farming and suburban areas. During the breeding season, females are known to construct their nests in rocky areas on hillsides. Areas with an abundance of tundra vegetation, coastal dunes, and marshes are preferred by this species.

• Habitat Regions
• temperate temperate
• polar polar
• terrestrial terrestrial

• Terrestrial Biomes
• tundra tundra

• Wetlands
• marsh marsh

• Other Habitat Features
• suburban suburban
• agricultural agricultural

Physical Description

Branta leucopsis in adult plumage has a rounded body, a rounded head, and a relatively short neck. The white feathers on the head cover a greater portion of the face than that of Branta canadensis (Canada goose). Overall, the face patch is white or often creamy-white and also extends to the forehead and under the throat. The black coloration of the neck extends below the chest. The ventrum of this species is white colored towards the posterior end and light-gray colored towards the anterior side. A black colored thin strip of feathers joins the eye and the bill. The feet are entirely black colored. The dorsal feathers are dark, bluish-grey. The tail is completely black both on its dorsal and ventral sides. The bill is black colored and short. The feather coloration above the wing is dark grey while the coloration below the wing is light, silvery-grey and white. Plumage is the same in both males and females of the species. However, males are usually larger in body size and weight than females. Adults weigh between 1.4 and 2.2 kg and feature a wingspan of 130 to 145 cm. Body length ranges from 55 to 70 cm.

Young adult barnacle geese (in their first winter) look very much the same as adults with slight plumage color variations. The black feathers of the neck and chest will often have a duller color compared to those of adults. It is possible to see a few brown feathers in the neck region as well. The faces of young birds may have few dark fleckings which can be hard to detect from a distance.

Downy young barnacle geese have grey-brown feathers on their dorsal parts, neck, chest, and crown. The ventrum of the downy young is pale-yellow. The line of feathers that extends from the bill to the eye is dark-grey colored. The feet and the bill are dark-grey colored as well. White spots are common on the wings.

Variation of plumage in adults has been observed but is rare. Adults with entirely dark brown to entirely white feathers have been observed in the past.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike
• male larger

Reproduction

Barnacle geese that have reached sexual maturity will choose their partners in early spring. Partner retention in Branta leucopsis is lifelong and monogamous. This partnership is believed to be established with a triumph ceremony in which the male will vocalize and change postures to impress the female. During this ceremony, the male will make loud calls and change the orientation and angle of his head relative to ground. If the female is willing to participate, she responds with loud calls and the male will increase the intensity of his movements and later try to approach the female. At times during the triumph ceremony, if a male catches the attention of a nearby female, he may exaggerate his displays by flicking his wings and lowering his head closer and more parallel to the ground. The goal of the male in this ceremony is to make contact with the female with his bill. If the female does not draw herself away, the male takes it as a sign of acceptance and forces all nearby males away. It is also believed that pairs may engage in the triumph ceremony each year to strengthen their partnership.

• Mating System
• monogamous monogamous

The breeding season occurs in spring, spanning from late May to June. Barnacle geese reaches sexual maturity at two years of age. However, rarely, males will be observed breeding at one year of age with females that are older. Barnacle geese that have mated for the first time at four years of age have also been recorded. It is believed that the age in which these geese mature may be related to environmental factors such as food availability and overall weather conditions. The female usually lays one egg per day until the desired clutch size (4 to 5 eggs) can be obtained. These eggs are pale gray colored. The clutch is incubated for 24 to 26 days and the young typically fledge 40 days after hatching.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• oviparous oviparous

Nests are constructed by females, often on cliff edges to avoid predators such as the arctic fox ( Vulpes lagopus ). Nest building materials include mud and dead foliage. Prior to laying her eggs the female lines the nest with down. The female will incubate the eggs for 24 to 26 days. During this time, the male will guard the nest and the female. During the incubation period, it is energetically costly to incubate and defend the eggs as the parents cannot forage far away from the nest. This causes both the female and the male to lose 30% to 40% of their total body weight. Barnacle goose hatchlings are precocial and leave the nest as soon as their downy feathers have dried. Parents lead their brood to marshes with abundant vegetation, but the young are entirely responsible for feeding themselves. The young are aggressively defended by both parents until they fledge and become independent after 40 to 45 days. Families remain together even after the young are considered independent. These family groups will perform their first migration together to the wintering grounds, but will disperse before the following breeding season as parents become increasingly territorial.

• Parental Investment
• precocial precocial
• male parental care male parental care
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • protecting
    • male
    • female
• pre-weaning/fledging
  • protecting
    • male
    • female
• pre-independence
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

In the wild, Branta leucopsis may live up to 25 years of age. In captivity where they are protected from predators and are provided sufficient food, they may live up to 30 years of age.

Behavior

Barnacle geese are migratory birds that travel between their breeding and overwintering grounds in the spring and fall. Barnacle geese breed in Greenland and the western coast of the Russian arctic and spend the winter in the British Isles and the western coast of Netherlands. Barnacle geese fly as a flock and make turns and twists as a group. The wingbeats are rapid. The flocks are closely packed and usually form lines during flight as opposed to a V-formation, however they have been observed to occasionally fly in V-formation.

In pair-bonded mates, the pairs stay close to each other. Often, the male keeps close proximity to his mate and protects her from predators and potential male rivals. Barnacle geese often breed colonially, so nests must be defended against close neighbors. Young adults tend to stay close to the adults in the flock, both while foraging and in flight. Parents stay together with their most recent brood until the following breeding season.

• Key Behaviors
• terricolous
• flies
• diurnal diurnal
• motile motile
• migratory migratory
• territorial territorial
• social social
• colonial colonial

Home Range

Branta leucopsis territorial during the incubation period and males vigorously defend the area around the nest. Exact territory size is unknown, but likely fluctuates in response to breeding densities.

Communication and Perception

Barnacle geese generate monosyllabic, rapid, loud calls to warn nearby geese of approaching predators. These calls often resemble the yapping of small dogs. They may generate loud calls to warn of aerial predators during flight as well.

Duets are usually performed during the mating season and serve the purpose of strengthening pair bonds between mates. A duet is often initiated by the male who makes short, rapid, loud calls. These calls are followed by similar loud calls from an interested female. Duets may also be initiated right after the initial mate selection in young barnacle geese. Vocal duets are often accompanied by visual displays by the male, who points his beak in alternating directions or holds his head close to the ground. If the female accepts his display, she allows him to approach and touch her with his bill.

During migration, barnacle geese are presumed to utilize magnetic fields to direct their flights.

Like most birds, barnacle geese perceive their environments through tactile, auditory, visual and chemical stimuli.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Other Communication Modes
• duets duets

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical
• magnetic magnetic

Food Habits

The species is herbivorous and mainly feeds on grass, aquatic vegetation, or human agricultural crops. On their breeding grounds, they will eat vegetation that is available in the tundra. In their wintering grounds they will often occupy fields and farmlands to feed on grass. This often causes a conflict with farmers.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• roots and tubers

Predation

During the breeding season in the arctic, top predators of this species are polar bears and Arctic foxes . Barnacle geese parents are known to aggressively physically defend their nests and young. Peregrine falcons are also known to hunt this species. During flight, if barnacle geese are threatened by aerial predators such as peregrine falcons, the flock adopts initiate fast turns in synchrony to confuse the attacker and avoid predation.

Ecosystem Roles

The species acts as a seed-dispersant for many grasses and is also a prey item for other species such as peregrine falcons, polar bears, and Arctic foxes.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Until the late 18th century, barnacle geese were considered to be non-meat food sources (due to beliefs that they were grown from barnacles) and was edible during Lent. Outside of Lent, the species was also hunted and consumed during their wintering stay in the British Isles by the coastal human populations. Currently, hunting and consumption of barnacle geese is prohibited by many governing bodies in both the British Isles and the European Arctic regions.

Economic Importance for Humans: Negative

This species is known to be considered pests by farmers in the British Isles and Netherlands. Barnacle geese often graze farmlands during their wintering months and reduce the soil quality, preventing farmers from obtaining high yields from their crops in the summer and early fall.

• Negative Impacts
• crop pest

Conservation Status

Barnacle geese are considered Least Concern by the International Union for Conservation of Nature and Natural Resources' (IUCN) Red List. Population sizes range from a few thousand to well over 100,000 and they are protected throughout their range. The Barnacle Goose Management Scheme in Scotland, United Kingdom makes efforts to protect barnacle geese from persecution by farmers during the wintering periods when the geese are frequent visitors to croplands. This conservation group helps farmers to make their land more suitable to supporting barnacle geese and also gives financial rewards to those that refrain from disturbing the birds on their property.

Other Comments

Early History (barnacles and geese): Barnacle goose gets its name from the early belief that the birds were born of barnacles in the sea shores. This was because the residents of the British Isles could not explain why the birds showed up in the summer and were absent in the winter.

Additional Information: During migratory flight, the heart rate of the barnacle goose can go up to a high of 315 beats per minute and a low of 225 beats per minute.

Additional Links

Encyclopedia of Life

Contributors

Utku Ekin (author), The College of New Jersey, Matthew Wund (editor), The College of New Jersey, Rachelle Sterling (editor), Special Projects.

References

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Butler, P., C. Bishop, A. Woakes. 2003. Chasing a Wild Goose: Posthatch Growth of Locomotor Muscles and Behavioral Physiology of Migration of an Arctic Goose. Pp. 527-542 in Avian Migration . New York: Springer.

Clements, J. 2007. The Clements Checklist of Birds of the World . Ithaca, New York: Cornell University Press.

Goodfellow, P. 1977. Birds as Builders . New York: Arco Publishing.

Gosler, A. 2007. Birds of the World: A Photographic Guide . New York: Firefly Books.

Harris, T. 2009. National Geographic: Complete Birds of the World . Washington, D.C.: National Geographic.

Jonker, R., M. Kuiper, L. Snijders, S. Van Wieren, R. Ydenberg, H. Prins. 2011. Divergence in timing of parental care and migration in barnacle geese. Behavioral Ecology , 22 (2): 326-331.

Ogilvie, M. 1978. Wild Geese . South Dakota: Buteo Books.

Sale, R. 2006. A Complete Guide to Arctic Wildlife . New York: Firefly Books.

Skutch, A. 1976. Parent Birds and Their Young . Austin: University of Texas Press.

Wheye, D., D. Kennedy. 2008. Humans, Nature, and Birds . New Haven: Yale University Press.

2011. "The IUCN Red List of Threatened Species" (On-line). Accessed February 24, 2011 at http://www.iucnredlist.org/ .