Arctic Tern Life Cycle: Nest Building To Fledging (and everything in between)

Arctic Tern Life Cycle: Nest Building To Fledging (and everything in between)

The Arctic tern, a slender bird with short legs and narrow wings, is known for its incredible long-distance travel. It flies from one end of the world to the other yearly. 

Depending on the season and their age, their colours change. Hatchlings are grey or brown, but as they mature, their feathers become grey or white during breeding season. 

Their beaks and legs are red, topped with a black spot on their head and forehead. In the off-season, the terns’ beak and legs darken, and the black spot on their head becomes smaller.

How Long Does An Arctic Tern Live?

Male Arctic Tern

Known for their extensive migrations and longevity, Arctic terns can live for several decades and typically start to breed when they’re around 3 to 4 years old. The oldest one on record was at least 34, captured and released in a banding project in Maine, USA.

How Fast Can An Arctic Tern Fly?

The flight speed of Arctic terns is roughly 35 to 40 kph (22 to 25 mph). During migration, they fly from 1,000 to 3,000 metres up and can go as fast as 55 kph (34 mph).

Arctic terns do not follow a straight route, which means they fly further than the expected 30,000 kilometres from the Arctic to the Antarctic each year. This ranks their migration as one of the longest in the animal kingdom.

Are Arctic Terns Aggressive?

The Arctic tern is known for its aggression when its nest is threatened, targeting intruders with its sharp beak. They are notably loud and social within their colonies, particularly in protecting their young from predators, much like other terns.

The Farne Islands and the Northern Isles are prime locations in the UK where large colonies of these birds are mostly found.

What Is An Arctic Tern’s Habitat?

Arctic Terns breed in open spaces on small islands and beaches along the northern Atlantic Coast, in areas without trees or plants on the ground, and in open boreal forests often near water bodies like lakes and rivers.

They search for food above bodies of water like lakes, rivers, ponds, and the ocean. They often migrate over the sea, but some may travel by land. They spend the winter near the pack ice in Antarctica when it is summer in the Southern Hemisphere.

How Long Does It Take For An Arctic Tern To Build A Nest?

Female Arctic Tern

The nest, made by both the male and female, is a shallow hole with some plant bits and other small items for lining. They build it on the ground in an open area and often with other tern species. While they sit in the nest, they often add materials like grass or stones to the rim. 

The simplicity of the nest means that Arctic Terns can finish building it in just a few days.

Eggs

Let’s take a look at the lifecycle of Arctic tern eggs, from laying to hatching, and how these birds fiercely defend their young.

When Do Arctic Terns Lay Eggs?

It’s common to see most Arctic terns sitting on their eggs by the start of June. Within weeks, a new generation hatches and the adults raise them until they’re able to fly on their own. 

Arctic terns protect their eggs and chicks with great determination, often involving clicking, taking flight, a lot of noise, and sometimes pecking at passers-by.

How Many Eggs Does An Arctic Tern Lay?

Generally, Arctic terns lay two eggs in each clutch, though sometimes this number can be one or three. Both the male and female share the job of incubating the eggs. 

What Do Arctic Tern Eggs Look Like?

The eggs of the Arctic Tern usually have spots and disguised, resembling rocks to fit in with their natural setting. They tend to have a light blue, green, or grey shade. This resemblance to stones helps guard the eggs against predators.

How Long Do Arctic Tern Eggs Take To Hatch?

It takes between 22 and 27 days for the eggs to hatch and another 21 to 24 days before they can fledge. Disturbances to the parents can prolong the incubation to as long as 34 days.

Chicks

Arctic tern chick

Let’s now take a look at the early stages of Arctic Tern chicks’ lives, including how many hatch, their first days of life, and when they begin to fly.

How Many Chicks Does An Arctic Tern Have?

As mentioned earlier, Arctic Terns lay between one and three eggs per breeding season, most often two. But not all the eggs may hatch into chicks.

Factors affecting egg hatching include infertile eggs, extreme weather, and human disturbance that can lead to birds leaving or damaging the eggs.

When Do Arctic Tern Chicks Open Their Eyes?

When chicks hatch, they have soft down and open eyes. They are semi-independent, starting to explore their surroundings within one to three days. Most can swim at two days old and they usually stay near their nest.

When Do Arctic Tern Chicks Fledge?

For the first 10 days, both Arctic tern parents look after their chicks. The chicks then start flying 21-28 days after hatching but continue to be fed by their parents for much longer, around 1-2 months. These birds will not breed the next year and will not migrate north.

SEE ALSO: Arctic Tern Diet and Size: Feeding Habits, Predators, and Measurements

Frequently Asked Questions

What is the lifespan of an Arctic Tern?

The lifespan of an Arctic tern can extend for several decades, with the oldest recorded being at least 34 years old.

What colour are Arctic Tern eggs?

Arctic tern eggs are typically light blue, green, or grey with spots, resembling rocks to blend in with their natural environment.

Where is the Arctic Tern nesting habitat?

The Arctic tern nesting habitat includes open spaces on small islands and beaches along the northern Atlantic Coast, often near bodies of water such as lakes and rivers.

Are Arctic Terns aggressive?

Yes, Arctic terns are aggressive when their nest is threatened, targeting intruders with their sharp beaks and loud, social behaviour, especially in protecting their young.

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