Buller's Shearwater vs Barolo Shearwater

Buller's Shearwater

Ardenna bulleri

How to recognise a buller's shearwater?

Buller's Shearwater Identification Guide

The Buller's Shearwater is a striking medium-sized seabird identified by its sleek, aerodynamic body and graceful flight patterns. It possesses a striking appearance with dark gray upper parts contrasted by a pure white underbelly. The upper wings and back display a mix of gray and white patterns, which form a distinct 'M' shape when seen from above. The bird's tail is wedge-shaped, and its long, slender wings are adapted for gliding over the ocean. Males and females of the Buller's Shearwater are almost indistinguishable in appearance, exhibiting similar size and coloration. Both sexes share the same flattened bill and webbed feet, which are adaptations for their marine lifestyle. There is no significant sexual dimorphism, so distinguishing between them in the field can be challenging. Juvenile Buller's Shearwaters resemble adults but with subtle differences. Young birds often have slightly duller plumage and less distinct patterns on their upper parts. The 'M' pattern on the back may appear less prominent. Over time, as they mature and go through molt cycles, they attain the sharper contrast and clearer markings that characterize mature adults.

Size

18.1 in/15.0 - 17.5 oz

Habitat

Primary habitat

Buller's Shearwater typically inhabits the open waters of the Pacific Ocean, primarily around New Zealand. They are often seen in areas where the continental shelf meets deeper waters, utilizing ocean currents to forage for squid and small fish. These birds prefer temperate climates with access to plentiful marine resources.

Additional range

In addition to their primary habitat, Buller's Shearwaters have been observed extending their range to the northern Pacific during their non-breeding season. They have displayed adaptability by venturing into subtropical and cooler waters along the coasts, occasionally seen as far as California and Japan.

Range Map

What do buller's shearwaters like to eat?

Natural diet

The Buller's Shearwater primarily feeds on small fish and zooplankton found within pelagic marine environments. Their diet mainly consists of small schooling fish such as anchovies and sardines. They are also known to consume squid and krill, diving under water to catch their prey or sometimes seizing it while flying close to the surface. These birds often follow large marine predators or fishing boats, taking advantage of leftovers or the increased availability of prey items. Seasonal variations occur, and during certain months they may shift their diet focus based on the abundance of different prey species.

Bird feeders

Buller's Shearwaters are unlikely to visit terrestrial bird feeders as they are strictly oceanic birds. In typical garden settings where bird feeders are placed, one would not expect to attract a Buller's Shearwater. These birds do not consume seeds, suet, or fruit, as their diet is entirely based on marine sources. Observers interested in Buller's Shearwaters should look to see these birds in their natural habitat, the open sea, rather than trying to feed them in other settings.

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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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Buller's Shearwater

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Barolo Shearwater

Buller's Shearwater

Ardenna bulleri

Buller's Shearwater Identification Guide

The Buller's Shearwater is a striking medium-sized seabird identified by its sleek, aerodynamic body and graceful flight patterns. It possesses a striking appearance with dark gray upper parts contrasted by a pure white underbelly. The upper wings and back display a mix of gray and white patterns, which form a distinct 'M' shape when seen from above. The bird's tail is wedge-shaped, and its long, slender wings are adapted for gliding over the ocean. Males and females of the Buller's Shearwater are almost indistinguishable in appearance, exhibiting similar size and coloration. Both sexes share the same flattened bill and webbed feet, which are adaptations for their marine lifestyle. There is no significant sexual dimorphism, so distinguishing between them in the field can be challenging. Juvenile Buller's Shearwaters resemble adults but with subtle differences. Young birds often have slightly duller plumage and less distinct patterns on their upper parts. The 'M' pattern on the back may appear less prominent. Over time, as they mature and go through molt cycles, they attain the sharper contrast and clearer markings that characterize mature adults.

Size

18.1 in/15.0 - 17.5 oz

There's more to learn about Buller's Shearwater

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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 Buller's Shearwater from the Barolo Shearwater

Visual differences

Buller's Shearwater is noticeably larger, with a length of about 18 inches and a weight of 15-17.5 oz, compared to the Barolo Shearwater's 11-13 inches and 6 oz. Buller's has a distinctive gray and white plumage with a darker cap and back, while Barolo exhibits a more uniform dark upper side and white under. Buller's displays a slender, curved beak, whereas Barolo's is shorter and stubbier. These size and plumage distinctions, along with beak shape, aid in visual differentiation.

Key differences and behavior

Buller's Shearwater and Barolo Shearwater exhibit distinct behavioral and ecological differences. Buller's Shearwaters are oceanic nomads, migrating thousands of miles from New Zealand to the North Pacific and thriving on squid and small fish. They are pelagic birds, typically associated with open waters and nesting on offshore islands within burrowed tunnels. In contrast, Barolo Shearwaters are nocturnal and rely on star navigation. Found primarily around the Canary Islands, they prefer rocky coastal habitats, nesting in cliffs or crevices. Barolo Shearwaters engage in night-time courtship and feeding, focusing on small fish and squid, while Buller's Shearwaters are day-active foragers. Both have monogamous breeding practices but differ in habitat preference and activity patterns.