Barnacle Geese (Branta leucopsis) are medium-sized geese that breed in the Arctic regions of Greenland, Svalbard, and Russia. They are highly social birds that nest in colonies and migrate in large flocks to wintering grounds in Northern Europe. Barnacle Geese are one of the species of geese most adapted to nesting in the challenging conditions of the Arctic tundra.
Nesting
Barnacle Geese build their nests directly on the ground, on cliff edges, or on rocky outcrops. The female lines the nest with down feathers plucked from her own breast. Barnacle Geese typically lay between 3-5 eggs per clutch. The eggs are creamy white in coloration and about 3 inches long. The female begins incubating the eggs as soon as the first one is laid, which takes around 24-28 days until they hatch.
Here are some key facts about Barnacle Goose nests and egg-laying:
- Clutch size: 3-5 eggs
- Egg color: Creamy white
- Egg size: Around 3 inches long
- Incubation period: 24-28 days
- Nest location: On the ground, on cliffs, rocky outcrops
- Nest lining: Female’s down feathers
The table below summarizes the key information about Barnacle Goose nests and eggs:
| Clutch Size | Egg Color | Egg Size | Incubation Period | Nest Location | Nest Lining |
|---|---|---|---|---|---|
| 3-5 eggs | Creamy white | ~3 inches | 24-28 days | On ground, cliffs, rocky outcrops | Female’s down feathers |
Laying Period
The egg-laying period for Barnacle Geese coincides with the short Arctic summer. Barnacle Geese time their breeding cycle to make use of the burst of insect and plant life that allows goslings to grow quickly before the return of winter conditions.
Barnacle Geese arrive back at their Arctic breeding grounds in late May or early June. Egg-laying typically begins in early June. The female lays one egg every 1-2 days until the clutch is complete with 3-5 eggs. Therefore, the laying period for a Barnacle Goose clutch is approximately 3-5 days.
Here are some key facts about the Barnacle Goose laying period:
- Arrive in Arctic in late May/early June
- Egg-laying begins in early June
- Lay 1 egg every 1-2 days
- Complete clutch size 3-5 eggs
- Laying period approximately 3-5 days
This table summarizes the timing of egg-laying in Barnacle Geese:
| Arrival in Arctic | Egg-Laying Begins | Laying Interval | Clutch Size | Laying Period |
|---|---|---|---|---|
| Late May/Early June | Early June | 1 egg every 1-2 days | 3-5 eggs | 3-5 days |
Incubation
Once the Barnacle Goose has laid her full clutch, incubation begins. The female is mainly responsible for incubating the eggs, only leaving the nest for short periods to feed. The male will stand guard near the nest when the female is away. Barnacle Goose eggs hatch after an incubation period of 24-28 days.
Here are some key facts about Barnacle Goose incubation:
- Incubation begins when full clutch is laid
- Female incubates 24/7, leaving just to feed
- Male stands guard when female is away
- Incubation period 24-28 days
- Eggs hatch together
This table summarizes Barnacle Goose incubation behavior and timing:
| Start of Incubation | Main Incubator | Male Role | Incubation Length | Hatching |
|---|---|---|---|---|
| After full clutch laid | Female | Stands guard | 24-28 days | Eggs hatch together |
Clutch Size Variation
While 3-5 eggs is typical, Barnacle Geese may lay smaller or larger clutches depending on environmental conditions. In lean times with fewer resources, clutch sizes tend to be smaller. When resources are abundant, they may lay larger clutches. Some factors influencing clutch size include:
- Age of female – Younger, less experienced females tend to lay fewer eggs
- Time of season – Early nesters may lay larger clutches
- Food availability – More food means larger clutches
- Weather – Colder weather leads to fewer eggs
- Nest site – Better sites allow for more eggs
Here is the typical range of clutch sizes for Barnacle Geese:
- Average: 3-5 eggs
- Minimum: 2-3 eggs
- Maximum: 5-6 eggs
This table shows the variation in Barnacle Goose clutch size:
| Average | Minimum | Maximum |
|---|---|---|
| 3-5 eggs | 2-3 eggs | 5-6 eggs |
Egg Size
Barnacle Goose eggs average around 3 inches long. However, exact egg size can vary slightly based on the individual female. Heavier females tend to lay larger eggs than lighter females. The first 1-2 eggs laid also tend to be smaller, with the last few eggs of a clutch being the largest. Some factors influencing egg size are:
- Female size – Larger females lay larger eggs
- Female age – Older females lay larger eggs
- Egg laying order – First eggs are smaller
- Food availability – More food equals larger eggs
Here is the typical range of Barnacle Goose egg sizes:
- Average: 3 inches (7-8 cm)
- Minimum: 2.75 inches (7 cm)
- Maximum: 3.25 inches (8.5 cm)
This table depicts the variation in Barnacle Goose egg sizes:
| Average Size | Minimum Size | Maximum Size |
|---|---|---|
| 3 inches | 2.75 inches | 3.25 inches |
Egg Color
Barnacle Goose eggs are a creamy, off-white coloration. There can be subtle variations in exact egg color that depend on factors like the female’s diet. Females that eat more crustaceans and algae tend to lay eggs with a greener or blue-green tint. The eggs fade to a more yellowish color over time. When freshly laid, Barnacle Goose egg color ranges from:
- Creamy white
- Off-white
- Light brown
- Light green-blue
Here are some examples of typical Barnacle Goose egg color variations:
| Creamy White | Off-White | Light Brown | Light Green-Blue |
|---|---|---|---|
Nest Sites
Barnacle Geese nest in colonies, with nests built close together. They prefer islands and elevated sites near the coast that provide safety from arctic foxes and other predators. Typical nest sites include:
- Cliff edges
- Rocky outcrops
- Small islands
- Along rivers and lakes
- Coastal slopes
Advantages of these nest sites include:
- Elevated view to spot predators
- Steep and rocky terrain deters predators
- Close to coastal food sources
- Protection from flooding
Here are some examples of typical Barnacle Goose nesting habitats and sites:
| Cliff Edge | Rocky Outcrop | Small Island | Riverbank |
|---|---|---|---|
Predation
The arctic nesting grounds pose many threats to Barnacle Goose eggs and young. Key predators include:
- Arctic foxes
- Polar bears
- Norway rats
- Glaucous gulls
- Ravens
- Arctic wolves
- Snowy owls
Barnacle Geese have evolved several strategies to protect their nests from predators:
- Nesting in colonies – More birds to keep watch
- Elevated and hard to reach nest sites
- Aggressively mob predators
- Nesting near snow goose colonies – Geese help defend each other
- Circling overhead when predators are near
Even with these defenses, Barnacle Geese often lose some eggs and goslings to predation each year. However, their nesting strategy helps ensure the survival of most of the brood.
Migration
To survive the harsh arctic winter, Barnacle Geese migrate long distances to reach wintering grounds. Their migration includes:
- Autumn migration in September/October
- Wintering grounds in Northern UK, Netherlands, Denmark
- Return to Arctic in May
- Females depart earlier than males in spring
- Males help rear young and leave later
The cyclical migration helps ensure Barnacle Geese can take advantage of the brief arctic summer for breeding. Their wintering and staging grounds provide refuge through the winter before the flock returns north again.
Population Status
Due to focused conservation efforts, Barnacle Goose populations have rebounded after steep declines in the 20th century. Current global population estimates are:
- East Atlantic population – 600,000+
- Svalbard-Russia population – 80,000+
- Greenland population – 20,000+
Some current threats and conservation issues include:
- Climate change affecting Arctic nesting grounds
- Overgrazing issues on wintering grounds
- Positive population growth leading to crop damage conflicts
However, targeted conservation plans are working to monitor and sustainably manage Barnacle Goose populations across their range.
Conclusion
In summary, Barnacle Geese are highly adapted to nesting in the extreme conditions of the Arctic tundra. Key facts about their reproduction include:
- Clutch sizes of typically 3-5 eggs
- Laying period of 3-5 days
- Incubation lasts 24-28 days
- Nests on cliffs, rocky outcrops, islands
- Egg size averages 3 inches long
- Creamy white egg coloration
Their resilience in the harsh Arctic allows Barnacle Geese to raise the next generation of goslings to migrate south again each fall. With careful management of threats, Barnacle Goose populations should be sustainable into the future.
