Balearic Shearwater Vs Manx Shearwater: Key Differences Explained

Balearic Shearwater Vs Manx Shearwater: Key Differences Explained

Wondering if that seabird is a Balearic shearwater or a Manx shearwater?

While they might share some similarities, these birds have distinct traits. This guide will explain the differences you should look for, including size, colour, preferred habitat, calls, and nesting habits.

Continue reading to find out what makes them different.

Key Takeaways

  • Balearic shearwaters are larger in size and weight
  • Balearic shearwater’s upper body is dark brown, contrasting with its lighter underside.
  • Manx shearwaters have eerie sound calls while Balearic shearwaters produce loud cackles
  • Manx shearwaters reuse and sometimes modify burrows for nesting

What Is The Difference Between Balearic Shearwaters And Manx Shearwaters?

The key differences between Balearic Shearwaters and Manx Shearwaters can be seen in various aspects which includes;

Visual Differences

The Balearic Shearwater and the Manx Shearwater are quite different in appearance. 

The Balearic Shearwater is mostly dark, with a brown upper body and a lighter underside, and its wings are a consistent dark colour. The head is darker and blends into the body colour. 

In contrast, the Manx Shearwater stands out with a black upper body and white underbody. Its wings are black on top and white underneath, and it has a black head with white throat and cheeks.

Differences In Habitat

The Balearic Shearwater divides its time between land and sea. It nests on islands in the Mediterranean, mainly the Balearics, and feeds near the coast of Spain during the breeding season. After breeding, they migrate across the Atlantic.

Manx Shearwaters are genuine ocean residents. They nest on islands in the North Atlantic and only visit land during the night. They live mostly at sea, feeding while flying close to the water. Outside of breeding season, they travel long distances to the South Atlantic.

Nests & Eggs

Balearic Shearwater

Balearic and Manx Shearwaters both nest in colonies, returning to the same breeding spots and laying a single egg each season, a typical seabird strategy to focus resources on one chick. 

Despite these similarities, their nesting habits differ. Balearic Shearwaters prefer existing crevices on islands and cliffs, whereas Manx Shearwaters reuse burrows, sometimes modifying them. 

The Balearic Shearwater’s egg is laid earlier, between March and April, with an incubation of 48-52 days, compared to the Manx Shearwater’s early May laying and 47-55 days incubation.

Bird Calls

Manx Shearwater

Both Balearic and Manx Shearwaters are noted for their vocal sounds, but they mostly make these at night in their breeding colonies.

Balearic Shearwaters stay quiet while they are at sea, conserving their energy for loud and distinct calls once they arrive at their nesting sites. These calls are known as raucous cackles, which are likely used for communication and protecting their space in the colony.

Manx Shearwaters remain equally vocal during the night, though their calls differ. Commonly described as a spooky combination of cries and whispers, their calls have become part of local myths, where they’re referred to as “devil birds.”

Size & Weight

When comparing sizes, the Balearic Shearwater is the larger bird compared to the Manx Shearwater. Typically, Balearic Shearwaters range from 34 to 39 cm in length and have a wingspan between 78 and 90 cm, weighing in at 472 to 565 grams.

Manx Shearwaters, however, are smaller and sleeker in appearance. They typically range from 30 to 38 cm in length and have a wingspan between 76 and 89 cm. Their weight falls between 350 and 575 grams, with an average of 400 grams.

SEE ALSO: Balearic Shearwater Life Cycle: Nest Building To Fledging (and everything in between)

Frequently Asked Questions

What is the difference between the Manx and Balearic Shearwater?

The difference between Manx and Balearic Shearwaters lies in their size, colouration, habitat, and calls. Balearic Shearwaters are larger, with dark brown upper bodies and lighter undersides, while Manx Shearwaters have a black upper body and white underbody. Balearic Shearwaters nest in the Mediterranean and migrate across the Atlantic, whereas Manx Shearwaters nest in the North Atlantic and live mostly at sea. Additionally, Balearic Shearwaters produce loud cackles, and Manx Shearwaters have eerie, whispering calls.

How do you identify a Manx Shearwater?

You can identify a Manx Shearwater by its distinct black upper body and white underbody, along with black wings on top and white underneath. The bird has a black head with white throat and cheeks. Additionally, its eerie sounding calls during the night are another key identifier.

How big are Balearic Shearwaters?

Balearic Shearwaters are larger than Manx Shearwaters, typically ranging from 34 to 39 cm in length with a wingspan between 78 and 90 cm. They weigh between 472 and 565 grams, making them a notably larger seabird compared to their Manx counterparts.

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