Spot the barnacle geese: A new member of Icelandic breeders

The barnacle goose (Branta leucopsis) is a waterfowl (Anatidae) that belongs to the black geese genus (Branta). The black geese genus is often related to the New World in the West while the gray geese genus (Anser) is related to the Old World in the East, but these two genera mix in their most northern habitat. The barnacle goose species is characteristic of the Arctic. There are three main populations; one breed in Northeastern Greenland, another at Svalbard and the third in Northern Russia.

Looks and behavior

The barnacle goose is a medium-sized bird that weighs 2.6-4.9 lbs and is 22.8-27.6 in long. As for other geese, the sexes look alike though the male is a bit bigger. The barnacle goose has a black neck, throat, and breast but has a white belly. Its forehead, chins, and patch are white or creamy yellow. The wingspan is 52-57 in wide and both the back and wings are grayish. Juveniles have a brownish color on the back and their head is darker than that of the adults, but they all have black feet and a black bill.

The barnacle geese are migratory birds that arrive to Iceland in large flocks in early spring. The first bird appear in Southern Iceland at the beginning of April and start feeding before they continue their migration to Northeastern Greenland. The Icelandic population is originated from the abovementioned barnacle population who live in Greenland.

The male stands guard and protects the female while she feeds and accumulates energy for the upcoming nesting season. In spring, about 70% of the Greenland population stay at Húnavatnssýsla and Skagafjörður in Northwestern Iceland. The barnacle population in Greenland has grown in recent years and the reason for that growth is unclear. Some say it is thanks to more strict rules about the protection of the birds in Greenland, rather than a better hatching success. The population size in Greenland is at least 40 thousand breeding pairs. In the fall, that corresponds to about 80 thousand birds who arrive in Iceland and mix with the small local barnacle population.

Did you know?

  1. The honk of barnacle geese sounds like the barking of small dogs.
  2. The only place where barnacle geese are hunted is in Iceland, where about 2000 birds are shot each year.
  3. The barnacle geese must nest out of the reach of foxes. In Greenland, therefore, they usually nest in steep cliffs and in Iceland, they nest on small islets surrounded with deep water.
  4. The barnacle geese are the only black geese (Branta) that breed in Iceland. But its aunt, the brent goose (Branta bernicla), makes a stopover in Iceland each year before migrating to Greenland.
  5. Old Icelandic legends say that the barnacle geese do not hatch from eggs. People said the birds formed out of driftwood and that in the beginning, they were mainly Lepas anatifera, a common barnacle species.

The Icelandic barnacle goose

The Icelandic barnacle geese start egglaying in the middle of May, which is about 4 weeks earlier than other birds that migrate to Greenland. The clutches are 3-6 white eggs that weigh about 3.5 oz each. The nest is a bed on the ground that each bird makes from their droppings and surrounding material before insulating it with down. The Icelandic barnacle goose nests on small islands and islets that are surrounded by deep water. This is their best protection against the main predator, the arctic fox (Vulpes lagopus, previously Alopex lagopus). The female incubates the eggs but when they hatch, both sexes care for the goslings. The incubation takes about 25 days and the goslings leave the nest soon after hatching. Both the goslings and the adults feed on alpine bistort (Bistorta vivipara) and other vegetation from their surroundings.

The development of the Icelandic barnacle population

In September, barnacle geese from Greenland arrive in Iceland. They spread around the southern highlands where they feed on berries and other vegetation. They stop in Skaftafellsýslur in Southern Iceland and stay in farmlands or wetlands before continuing their migration to the wintering grounds in Great Britain.

The story of how the Icelandic barnacle population has developed throughout the years is an interesting one. The birds have long made a stopover in Iceland each spring, before migrating to their breeding grounds in Greenland where they nest in steep cliffs. At a certain point, some bird pairs decided not to continue their journey to Greenland but to nest in Iceland instead. The oldest documentation about this is from the year 1927, written in Hörgárdalur in Northern Iceland, and the next one is from 1963, written in Breiðafjörður in Western Iceland. The barnacle geese nested at Breiðafjörður for 20 years but after that, the population mostly stayed in southern parts of the country.

The Icelandic population grew very slowly and in 2005, there were about 20 nests in Iceland. A few years later, the barnacle geese settled in in East-Skaftafellssýsla and the population finally started growing faster. In 2014, there were about 500 nests in the country. Breeding in Southern Iceland continued to increase and in 2019, the number of nests in Skua island at Jökulsárlón exceeded 1000 nests. There are also many smaller colonies around the island. The barnacle geese are now considered an Icelandic breeder, with a population of about 2000 breeding pairs.

Links worth a click

Key information from the Royal Society for the Protection of Birds

What Oceanwide Expeditions wrote about the barnacle goose

A great page on The Wildlife Trusts’ website

Author: Dr. Þórður Örn Kristjánsson
Photographer: Ragnar Th. Sigurðsson