Arctic Skua Eggs to Chicks: Hatching, Development, and Fledging

Arctic Skua Eggs to Chicks: Hatching, Development, and Fledging

In the UK the arctic skua population is confined to areas in north and west Scotland. They nest in moorland often in close proximity to guillemots, razorbills, puffins, kittiwakes and arctic terns.

Arctic skuas commonly obtain their food by stealing from these other bird species. They intimidate birds in the air and get them to drop their food which the arctic skuas then steal. 

They also take eggs and chicks from the nests of neighbouring birds to feed themselves and their young.

In this article we’ll be looking at how many eggs arctic skuas lay as well as how long they take to hatch and many other interesting facts. Keep reading to find out more.

Arctic Skua Egg Laying & Development

Let’s look into the life cycle of the arctic skua from egg laying to the fledging of the chicks.

How Many Eggs Does An Arctic Skua Lay

Arctic skuas make their nests by making a depression in the ground with their feet which is then lined with plant material. The nest is typically situated on a slight mound with clear access to the sea.

The female typically lays two eggs which are around 58 x 40 mm in size and weigh around 48 grams. That’s around the equivalent weight of 2 alkaline AA batteries.

They only raise one brood each year and lay their first brood in their second year as this is when they reach sexual maturity. In many cases, only one egg actually survives long enough to hatch and become a fully fledged bird.

Many are lost to predators like foxes or snowy owls or are stolen by other birds.

What Do Arctic Skua Eggs Look Like?

The arctic skua’s eggs are a dark olive/brown colour with darker speckles. These eggs tend to blend in with the nest site making them difficult to see from a distance.

Like most ground nesting birds this camouflage of the eggs is necessary in order for the survival of their young.

Although both parents are available to incubate the eggs, there are times when one or both eggs get taken by owls, foxes or other members of their own community.

How Long Do Arctic Skua Eggs Take To Hatch?

Arctic skuas typically lay their eggs in early July. The eggs are incubated by both parents for around 26 days. The eggs typically hatch around the last week of July or very early August.

Once the eggs hatch, both parents feed the chicks who, like most ground nesting birds, leave the nest relatively quickly after hatching.

Although both parents take part in the incubation of the eggs, it is mainly the female who is responsible for the brooding. With the male flying off to get food for both of them.

When Do Arctic Skua Chicks Open Their Eyes?

Arctic skua chicks are precocial which means they are hatched, covered in down and with their eyes open. They must open their eyes while still inside the egg and use their eyes to help them identify how to break through the eggshell.

This is a useful survival skill as it allows them to leave the nest very soon after hatching. Obviously they are at their most vulnerable when first hatched and the nest is a target for many predators.

When Do Arctic Skua Chicks Fledge?

Like all precocial birds that are hatched with their eyes open and covered in down, arctic skua chicks leave the nest after around 24 to 48 hours after hatching.

They are fed by both parents on regurgitated food and stay with their parents until they are around 26 to 30 days old. At which point they fledge the nest. 

If the parents notice any predators getting too close to the nest or the newly fledged chicks, they display the symptoms of a broken wing to lure the attacker away from the nest.The young birds are typically fully fledged by the end of September and ready to start their own life out at sea.

They quickly learn how to harass other birds in order to steal their food as well as eating wader birds chicks, bird’s eggs, small rodents, passerines and other small bird species, insects, berries and dead animal flesh.

Are Arctic Skuas A Threatened Species?

Male Arctic Skua

Although eggs and young chicks are widely hunted by foxes and owls, the arctic skua is not currently on the threatened species list.

Once fully fledged, the arctic skua spends most of its life out at sea. Only returning to land to nest and reproduce. It’s at this time when they are most vulnerable.

If the chicks make it past fledgling, they are fairly safe and usually survive until they reach sexual maturity (at around age 2 or 3). 

Having said that, their numbers are dwindling in Scotland. In fact there has been an 81% decline in numbers recorded in the Shetland Isles since 1986.

There are no certain causes for this decline although there have been a couple of theories. Which are;

  1. The decline in the number of sand eels off the Shetland coasts
  2. Excessive predation & competition from Great Skuas

Both of which could very well be contributing factors. The behaviour of nesting arctic skuas on the Shetland Isles were monitored and it was found that they are having to forage out to sea further than was ever recorded before which backs the sand eel decline theory.

Added to the increased population of great skuas also residing in the same areas which supports the second theory.

How Do Arctic Skuas Hunt For Food?

The arctic skua is also known as the parasitic jaeger, which means parasitic hunter. They have an easy active flight pattern with fast beats of their wings intermingled with wing glides in large arcs when flying over the wave tops.

They attack other seabirds for food with the attack starting with a low flight before suddenly rising up high for the final attack. The skua then performs a series of turns and dives.

Although arctic skuas never actually attack the other bird at all, but as it pursues it at great speed, the other bird regurgitates its food which is then caught by the skua.

This is a clever tactic as it doesn’t involve any actual fighting which could lead to injury. Instead it’s the threat of violence which makes the other bird concede its food.

SEE ALSO: Aquatic Warbler Life Cycle: From Nest Building to Flight

Frequently Asked Questions

What Colour Are Arctic Skua Eggs?

Arctic skua eggs are a dark olive brown colour with dark speckles.

How Long Does It Take For Arctic Skua Eggs To Hatch?

Arctic skua eggs are incubated by both parents and hatch after around 26 days.

When Do Arctic Skua Eggs Hatch?

Arctic skuas tend to lay their eggs at the beginning of July and are incubated for around 26 days which means they typically hatch at the end of July or the beginning of August.

How many eggs do Arctic Skuas lay?

Arctic skuas typically lay 2 eggs. They only have one brood per year and often only one egg survives to full maturity.

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