Manx Shearwater Life Cycle: Nest Building To Fledging (and everything in between)

Manx Shearwater Life Cycle: Nest Building To Fledging (and everything in between)

Manx shearwaters, with their white and sooty black feathers, are medium-sized seabirds and masters of sea navigation, though they’re rarely spotted on land. 

During the breeding season, Manx Shearwaters remain out at sea until darkness falls before returning to their steep, hard-to-access nesting sites, mainly on the western coast.

These long-lived birds prefer not to be on land during daylight hours and typically spend significant time gliding on stiff wings low over the sea, covering great distances even outside the breeding season.

How Long Does A Manx Shearwater Live?

Manx shearwaters are known for their long lives, making them the oldest birds in Britain. Known for their enigmatic allure, they symbolise the conservation achievements of the Scilly islands. These birds usually live for around 15 years, yet under the best conditions, they can survive much longer.

The oldest known wild bird in the world in 2003/04 was a Manx shearwater from Copeland Island, Northern Ireland. First ringed as an adult of at least 5 years old in July 1953, it was recaptured in July 2003, being at least 55 years old.

How Fast Can A Manx Shearwater Fly?

Manx Shearwater

Manx Shearwaters are known to reach speeds of about 55 km per hour. This impressive speed allows them to cover great distances over the ocean.

Additionally, Manx shearwaters use dynamic soaring, which lets them make the most of wind gradients, saving a lot of energy. This way of flying is especially useful in windy weather, allowing them to keep up higher speeds with less effort.

Are Manx Shearwaters Aggressive?

Manx shearwaters are not usually aggressive birds. They are mostly sociable and peaceful, although they can be aggressive when securing a nesting area. 

In the breeding season, they might protect their nests like other birds, but there is no specific mention of them being notably aggressive towards humans or other animals. 

What Is A Manx Shearwater’s Habitat?

The Manx shearwater is a bird that lives entirely at sea, usually flying within 10 metres (30 ft) above the water. 

They choose to nest in burrows located on small islands, and only visit these nests at night. These nesting areas are found in the north Atlantic Ocean, in countries such as the UK, Iceland, Ireland, France, the Channel Islands,the Faroe Islands, the Azores, the Isle of Man, Madeira, and the Canary Islands.

When not in breeding season, Manx shearwaters journey widely to the South Atlantic, spending the winter near the shores of Argentina and Brazil, which proves their ability for long journeys.

How Long Does It Take For A Manx Shearwater To Build A Nest?

Manx Shearwater

Although shearwaters can dig their own holes, Manx shearwaters are known to repeatedly use existing burrows, avoiding the need to build new ones. These burrows, often extending 3-6 feet, may be slightly altered or expanded over time. The combined efforts of both parents in burrow preparation could make the setup quicker.

This information suggests that Manx shearwaters might not spend much time constructing new nests from scratch. Instead, they seem to focus on upgrading and adjusting existing burrows for breeding, usually by adding grass and leaves.

Eggs

Let’s look at when Manx Shearwaters lay their eggs, how many they lay, what the eggs look like, and how long they take to hatch.

When Do Manx Shearwaters Lay Eggs?

While shearwaters return to their breeding grounds from March, the females often depart again for 2–3 weeks before laying eggs in early May. 

How Many Eggs Does A Manx Shearwater Lay?

Each breeding season, Manx shearwaters produce a single egg. 

The egg is incubated by both male and female Manx shearwaters, typically for 47 to 55 days, though it can sometimes take up to 63 days.

What Do Manx Shearwater Eggs Look Like?

On average, the single white egg laid by a Manx Shearwater is 61 mm long and 42 mm wide, weighing around 57 grams (2 oz), and its shell accounts for 7% of the total weight.

How Long Do Manx Shearwater Eggs Take To Hatch?

The chicks of the Manx Shearwater hatch after 51 days, which is one of the longest breeding times among seabirds on Skomer Island, Wales. 

In this period, both parents share the task, alternating incubation shifts of around 6 days each

Chicks

Let’s see what life is like for young Manx Shearwaters, from how many there are to when they open their eyes and finally leave the nest.

How Many Chicks Does A Manx Shearwater Have?

As previously mentioned, Manx shearwaters lay one egg every breeding season. They tend to focus all their energy on nurturing one chick at a time. 

This approach is typical among many seabird species, who invest much care and protection in their single offspring.

When Do Manx Shearwater Chicks Open Their Eyes?

While there’s no precise timing of when Manx shearwater chicks open their eyes, they are altricial. And generally speaking, it takes altricial birds 7 days before they can open their eyes.

This also means they are dependent on their parents for sustenance and warmth for an extended period. Manx shearwaters are known for their dedicated parental care, with both parents contributing to feeding and protecting the chick until it is ready to fly.

This significant level of parental effort aligns with altricial bird species, which rely heavily on their parents for support from the moment they hatch.

When Do Manx Shearwater Chicks Fledge?

The fledging period lasts about 70 days, so the chicks don’t leave until late August, early September, or October. Manx Shearwater parents don’t guide their chicks. Instead, the adults leave first, and the young survive on their fat reserves.

SEE ALSO: Manx Shearwater Diet and Size: Feeding Habits, Predators, and Measurements

Frequently Asked Questions

What is the lifespan of a Manx Shearwater?

The lifespan of a Manx Shearwater is typically around 15 years; however, under optimal conditions, they can live significantly longer, with records of these birds living up to 55 years or more.

What colour are Manx Shearwater eggs?

Manx Shearwater eggs are white in colour.

Where do Manx Shearwaters nest?

Manx Shearwaters nest in burrows located on small islands in the North Atlantic Ocean. These locations include the UK, Iceland, Ireland, France, the Channel Islands, the Faroe Islands, the Azores, the Isle of Man, Madeira, and the Canary Islands.

Are Manx Shearwaters aggressive?

Manx Shearwaters are not usually aggressive. They are predominantly sociable and peaceful, although they can show aggression when protecting their nesting areas during the breeding season.

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