Barnacle geese are migratory birds that breed in the Arctic and winter in temperate regions. Their annual migratory journey takes them thousands of miles between their Arctic breeding grounds and wintering sites in Europe and along the Atlantic coast of North America.
When do barnacle geese migrate?
Barnacle geese migrate twice a year, in spring and autumn. The timing of their migration depends on the population:
- Russian barnacle geese leave their wintering grounds in early April and arrive on the breeding grounds in late May. They start their autumn migration in late August/early September and arrive at their wintering grounds in November.
- East Atlantic barnacle geese depart their wintering grounds in Scotland and Ireland in April and reach the Arctic coast of Svalbard, Norway in May to breed. They leave the Arctic in September and return to Scotland/Ireland in October to overwinter.
- Greenland barnacle geese leave Ireland in early May and arrive in west Greenland to nest in June. They start moving south in late August, reaching Ireland again in October/November.
The exact timing varies year-to-year depending on weather conditions. But in general, barnacle geese migrate north to their breeding grounds during a short spring window and then head south to their wintering grounds in the fall.
Where do barnacle geese migrate between?
There are three main populations of barnacle geese with distinct breeding and wintering areas:
- Russian barnacle geese – Breed on the Arctic islands of Novaya Zemlya and Vaigach Island. Winter on the Solway Firth in the UK, along the North Sea coast, and in the Netherlands.
- East Atlantic barnacle geese – Breed on Svalbard, an Arctic archipelago of Norway. Winter in northwest Scotland, Ireland, and western Denmark.
- Greenland barnacle geese – Breed in east and west Greenland. Winter primarily on Islay and other islands in southwest Scotland.
During migration, barnacle geese stop to rest and feed in countries such as Denmark, Germany, and Estonia. Their migratory routes span thousands of miles between the tundra nesting grounds and relatively mild coastal wintering sites.
How far do barnacle geese migrate?
Barnacle geese undertake an extremely long distance migration twice per year. Some key migration distances include:
- Russian barnacle geese – Breeding to wintering grounds: 2,400-2,800 km (1,500-1,700 miles)
- East Atlantic barnacle geese – Breeding to wintering grounds: 2,600-3,000 km (1,600-1,900 miles)
- Greenland barnacle geese – Breeding to wintering grounds: 3,000-4,200 km (1,900-2,600 miles)
That means a single barnacle goose may migrate more than 8,000 km (5,000 miles) per year back and forth between nesting and wintering areas. Their migrations are among the longest of any goose species.
What is their migration route?
The migration routes of the three barnacle goose populations can be summarized as:
- Russian – Stage in Baltic region then fly over North Sea to winter in UK and Netherlands
- East Atlantic – Stage in Norway then fly over North Sea to winter in Scotland and Ireland
- Greenland – Stage in Iceland then fly over Atlantic Ocean to winter in southwest Scotland
During both spring and autumn migrations, barnacle geese generally follow coastlines and avoid crossing large expanses of open ocean as much as possible. But Greenland barnacle geese do make a nonstop transoceanic flight of 800-1,000 km between Iceland and Scotland twice per year.
Why do barnacle geese migrate such long distances?
There are a few key reasons why barnacle geese migrate thousands of miles between Arctic breeding areas and temperate wintering regions:
- Nesting habitat – They require remote, predator-free Arctic tundra to successfully rear young.
- Food availability – The tundra provides abundant food in summer but very little in winter.
- Weather extremes – The Arctic is extremely cold in winter, making it an inhospitable place.
- Day length – Increased daylight hours in the Arctic summer allow more time to find food.
By migrating long distances, barnacle geese take advantage of the best conditions and resources during breeding season as well as milder winters. Their migratory behavior maximizes gosling survival and adult nutrition annually.
How do barnacle geese navigate their migrations?
Barnacle geese rely on a combination of instincts and learned behaviors to navigate their biannual migrations through changing landscapes and weather:
- Instinct – They have innate abilities to orient using cues like the sun, stars, and Earth’s magnetic field.
- Learning – Migration routes and stopover sites are culturally transmitted from older to younger geese.
- Memory – They form cognitive maps and recall landmarks and environmental features.
- Flexibility – Barnacle geese can alter their course and stopovers based on weather, food resources, and other conditions.
Their navigational abilities enable barnacle geese to make their exceptionally long seasonal movements with great accuracy and precision, year after year.
What are the threats to barnacle geese during migration?
Barnacle geese face a variety of threats and challenges during their long-distance migrations which lead to mortality. Some key threats include:
- Habitat loss – Wetlands and grasslands used for stopovers are being degraded and converted to agriculture and urban areas.
- Disturbance – Geese are sensitive to noise, lights, and human presence which interrupts feeding and resting.
- Hunting – Barnacle geese are still legally hunted for sport and food in some regions.
- Power lines – Collisions with power lines and wind turbines are a collision risk.
- Predators – Golden eagles, foxes, and other predators take geese, especially weakened migrants.
- Pollution – Oil spills, agricultural runoff, and garbage impact staging and wintering wetland habitats.
Conservation efforts aim to protect important wetlands along migration flyways and minimize disturbances to barnacle geese from human activities during critical seasonal movements.
How has migration changed over time?
Some key changes have occurred in barnacle goose migration patterns and habits over past decades:
- Shortened migration distances due to increasing use of agricultural fields near wintering sites.
- Shifts from coastal to more inland wintering regions in some populations.
- Earlier spring departure and delayed autumn arrival at breeding grounds due to climate change.
- Altered migration routes and decreased stopover times due to habitat loss.
- Increased reliance on human-created habitats due to wetland degradation.
Their flexibility and ability to adapt has allowed barnacle geese to shift migration patterns in response to environmental conditions and habitat availability. But further changes may threaten their unique long-distance migratory behavior.
Conclusion
In summary, barnacle geese are champion migrants that complete annual round-trip journeys of up to 8,000 km or more between Arctic breeding grounds and wintering regions in temperate coastal areas. Their ability to navigate precise migratory routes across continents and ocean basins reflects both innate capacities and learned knowledge that develops through experience. While facing growing threats from human activities, barnacle geese continue to embark on their strenuous migratory travels each year – a remarkable wildlife phenomenon spanning hemispheres that remains essential for their survival and propagation.