Bulwer's Petrel vs Barolo Shearwater

Bulwer's Petrel

Bulweria bulwerii

How to recognise a bulwer's petrel?

General appearance

The Bulwer's Petrel is a medium-sized seabird characterized by its sleek, elongated body and narrow wings that enable graceful gliding over the water. Its plumage is primarily a dark chocolate brown, often appearing black in dim lighting. The head, back, and wings possess a slight sheen, adding to its striking appearance. The bird's bill is slender and black, complementing its streamlined body. Legs and feet are also dark, aiding in its inconspicuous presence at sea.

Male vs female

In Bulwer's Petrels, sexual dimorphism is minimal. Both males and females share similar size and coloration, making it difficult for observers to distinguish between the sexes. They are nearly identical in plumage and size, with no discernible differences in markings or color.

Juvenile

Juvenile Bulwer's Petrels closely resemble adults, sharing the same dark plumage. However, younger birds might display slightly more faded or dusky feathering compared to the polished look of mature adults. While the overall structure remains similar, juveniles might appear a bit scruffier as they transition into adults. Over time, their plumage gains the sheen characteristic of adult Bulwer's Petrels, completing their development.

Size

9.8 - 11.0 in/3.0 - 4.8 oz

Habitat

Habitat of the Bulwer's Petrel

Primary habitat: Bulwer's Petrel primarily inhabits subtropical and tropical oceanic waters. They are found across the Atlantic, Pacific, and Indian Oceans. Preferring warmer climates, they nest on remote islands with cliffs or rocky outcrops where vegetation provides adequate cover from predators. Additional range: While their primary range is over open seas, they can sometimes be sighted closer to coastal regions during breeding seasons. Despite their pelagic nature, these birds occasionally venture near islands not commonly used for nesting, demonstrating some level of adaptability to varying maritime environments.

Range Map

What do bulwer's petrels like to eat?

Natural diet

Bulwer's Petrel, a pelagic bird found across the subtropical and tropical oceans, primarily sustains itself on a maritime diet. Its primary food sources include small fish, squid, and crustaceans. Specialized for life at sea, these petrels are adept at catching prey near the water's surface, often during the night when marine life ascends closer to the surface. They take advantage of their excellent low-light vision to forage effectively in the dark. Seasonal shifts impact their diet minimally, as their aquatic prey remains available year-round. However, certain fluctuations in oceanic food availability can influence specific diet composition depending on geographical location.

Bird feeders

As a strictly oceanic bird, Bulwer's Petrel rarely, if ever, frequents traditional land-based bird feeders because they are well-adapted to sourcing food from the open ocean. Unlike many common backyard birds that enjoy a range of seeds, fruits, or suet offered at feeders, the Bulwer's Petrel's diet is specialized for catching marine food items. Human attempts to supplement their diet using bird feeders would unlikely succeed, as the petrels seldom approach terrestrial environments for feeding purposes and are specifically reliant on their natural oceanic habitat to meet their dietary needs.

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Barolo Shearwater

Puffinus baroli

How to recognise a barolo shearwater?

General Appearance

The Barolo Shearwater is a small seabird, typically measuring about 27-30 cm in length with a wingspan ranging between 67-72 cm. Its plumage is predominantly black and white, with the upper parts including the back and wings being a rich black while the underparts, including the belly and underwings, are a bright white. A distinct and thin black band runs across the leading edges of the wings, visible in flight. Their beak is slender and dark gray, complementing their small rounded head. Legs and feet are also dark, often having a slightly bluish tint.

Male vs Female

The Barolo Shearwater shows no significant sexual dimorphism as both males and females have similar size and plumage. This similarity in appearance makes it challenging to distinguish their sexes visually in the wild. Observations during the breeding season might provide slight variations in behavior rather than physical characteristics. Hence, both sexes are equally involved in nesting duties, including incubation and feeding of the chicks.

Juvenile

Juvenile Barolo Shearwaters differ slightly from adults primarily in the sharpness and intensity of their plumage colors. Younger birds may appear duller with a less distinct contrast between the black and white areas. The feather edges in juveniles often have a slightly frayed look as they transition into adult plumage. As they mature, they quickly take on the brighter and more defined coloration seen in adults. However, there are no drastic changes in size or shape between juveniles and adults.

Size

11.0 - 13.0 in/6.0 oz

Habitat

Primary Habitat

The Barolo Shearwater primarily inhabits subtropical and temperate marine environments. They are typically found around the Canary Islands, Azores, and Madeira. These seabirds prefer open oceans and coastal waters, especially during breeding periods, where they nest in cliffs and rocky shores to take advantage of sea breezes for effortless take-off.

Additional Range

Though mainly found in the Atlantic near their breeding grounds, Barolo Shearwaters have been spotted in less expected areas like the North Sea and off the western coasts of Africa. This indicates their adaptability and occasional ventures outside subtropical zones, possibly driven by changing food availability or migratory patterns.

Range Map

What do barolo shearwaters like to eat?

Natural diet

The Barolo Shearwater primarily feeds on small fish and squid found in their marine environment. Their diet largely consists of forage fish such as anchovies, sardines, and other small shoaling species. During the breeding season, they may also consume crustaceans and plankton available in the Atlantic Ocean. These birds are adapted to plunge-diving and surface-seizing techniques to catch their prey. Seasonal variations in their diet occur, as they travel across different ocean regions, yet small fish remain the core component.

Bird feeders

Barolo Shearwaters do not typically visit terrestrial bird feeders. As marine birds, their dietary habits are not well-suited for land-based feeder offerings like seeds, fruits, or suet. Their nutritional needs are met via their oceanic diet, which provides essential proteins and oils. Consequently, setting up a conventional bird feeder would not attract these seabirds. However, preserving their natural habitats and ensuring healthy ocean ecosystems are crucial for their sustenance. Efforts to keep coastal and marine areas free of pollution and disturbances can indirectly support their dietary needs.

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Bulwer's Petrel

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Barolo Shearwater

Bulwer's Petrel

Bulweria bulwerii

General appearance

The Bulwer's Petrel is a medium-sized seabird characterized by its sleek, elongated body and narrow wings that enable graceful gliding over the water. Its plumage is primarily a dark chocolate brown, often appearing black in dim lighting. The head, back, and wings possess a slight sheen, adding to its striking appearance. The bird's bill is slender and black, complementing its streamlined body. Legs and feet are also dark, aiding in its inconspicuous presence at sea.

Male vs female

In Bulwer's Petrels, sexual dimorphism is minimal. Both males and females share similar size and coloration, making it difficult for observers to distinguish between the sexes. They are nearly identical in plumage and size, with no discernible differences in markings or color.

Juvenile

Juvenile Bulwer's Petrels closely resemble adults, sharing the same dark plumage. However, younger birds might display slightly more faded or dusky feathering compared to the polished look of mature adults. While the overall structure remains similar, juveniles might appear a bit scruffier as they transition into adults. Over time, their plumage gains the sheen characteristic of adult Bulwer's Petrels, completing their development.

Size

9.8 - 11.0 in/3.0 - 4.8 oz

There's more to learn about Bulwer's Petrel

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Barolo Shearwater

Puffinus baroli

General Appearance

The Barolo Shearwater is a small seabird, typically measuring about 27-30 cm in length with a wingspan ranging between 67-72 cm. Its plumage is predominantly black and white, with the upper parts including the back and wings being a rich black while the underparts, including the belly and underwings, are a bright white. A distinct and thin black band runs across the leading edges of the wings, visible in flight. Their beak is slender and dark gray, complementing their small rounded head. Legs and feet are also dark, often having a slightly bluish tint.

Male vs Female

The Barolo Shearwater shows no significant sexual dimorphism as both males and females have similar size and plumage. This similarity in appearance makes it challenging to distinguish their sexes visually in the wild. Observations during the breeding season might provide slight variations in behavior rather than physical characteristics. Hence, both sexes are equally involved in nesting duties, including incubation and feeding of the chicks.

Juvenile

Juvenile Barolo Shearwaters differ slightly from adults primarily in the sharpness and intensity of their plumage colors. Younger birds may appear duller with a less distinct contrast between the black and white areas. The feather edges in juveniles often have a slightly frayed look as they transition into adult plumage. As they mature, they quickly take on the brighter and more defined coloration seen in adults. However, there are no drastic changes in size or shape between juveniles and adults.

Size

11.0 - 13.0 in/6.0 oz

There's more to learn about Barolo Shearwater

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How to tell the Bulwer's Petrel from the Barolo Shearwater

Visual differences

Bulwer's Petrel is smaller and lighter, weighing 3-4.8 ounces with a length of 9.8-11 inches, featuring uniform dark chocolate-brown plumage. In contrast, the Barolo Shearwater is heftier at 6 ounces with a length of 11-13 inches, and displays a striking black-and-white contrast, with a white underside and black upper parts. Bulwer's has a slender black bill, while Barolo's is more robust and dark. The distinct plumage styles and size differences are key visual identifiers between the two seabirds.

Key differences and behavior

Bulwer's Petrel and Barolo Shearwater, both nocturnal seabirds, exhibit distinct behavioral traits. Bulwer's Petrel, found in subtropical and tropical waters, prefers remote islands for nesting. Their breeding includes aerial acrobatics and calls, while they feed on small fish and squid at night, employing low-light vision. Barolo Shearwater inhabits temperate marine environments such as the Canary Islands, showcasing zigzag flight patterns and gentle cooing calls. They nest on cliffs, utilizing synchronized movements for courtship and rely on plunge-diving to catch fish. Both species form monogamous bonds, but Bulwer's Petrel exhibits a more humor-infused vocalization compared to the softer, melodic calls of Barolo Shearwater.