Flesh-footed Shearwater vs Black-vented Shearwater

Flesh-footed Shearwater

Ardenna carneipes

How to recognise a flesh-footed shearwater?

General appearance

The Flesh-footed Shearwater is recognized by its uniform dark plumage, with feathers ranging from warm brown to almost black. Its flesh-colored legs and feet are striking against the dark body. The bill is pale, broad, and hooked at the tip, which helps distinguish it from similar species. The sheer size of this bird can also be notable, as it measures approximately 40-45 centimeters in length, with a wingspan of around 99-107 centimeters. The wings are long and slender, enabling it to glide effortlessly over the ocean.

Male vs female

There is very minimal sexual dimorphism in the Flesh-footed Shearwater, making it challenging to differentiate males from females based solely on appearance. Both sexes display the same dark plumage and flesh-colored feet. Their sizes are also comparable, with no significant variance in weight or wingspan that would aid identification.

Juvenile

Juvenile Flesh-footed Shearwaters closely resemble adult birds in coloration and size. However, juveniles can be identified by their slightly less worn feather quality, often appearing fresher and less glossy than those of adults. They might also venture closer to breeding colonies as they explore their surroundings, offering a clue to their age.

Size

15.7 - 18.9 in/22.9 - 28.6 oz

Habitat

Primary Habitat

The Flesh-footed Shearwater primarily inhabits the open oceans and coastal waters of the southern hemisphere. Its typical range includes the warm temperate and subtropical regions of the Indian and Pacific Oceans. They regularly breed on islands off Australia and New Zealand, favoring burrows on sloped terrains with vegetation that offer shelter.

Additional Range

Beyond their main habitat, these birds might adapt to cooler waters, venturing into more northern latitudes during non-breeding seasons. Occasionally, they are observed in unexpected coastal areas, attracted by food availability, particularly during migratory journeys.

Range Map

What do flesh-footed shearwaters like to eat?

Natural diet

The Flesh-footed Shearwater, which inhabits open ocean areas, predominantly feeds on marine prey. Its diet mainly consists of fish, squid, and crustaceans, which it catches by surface seizing during gliding flights. The bird's feeding behavior shows some seasonal variation, with a higher intake of squid during breeding seasons when they are most abundant. Due to its pelagic lifestyle, the Flesh-footed Shearwater relies heavily on the availability of shoaling fish, benefiting from the natural processes and upwellings that bring prey to the ocean surface.

Bird feeders

Flesh-footed Shearwaters do not visit land-based bird feeders or consume typical feeder offerings such as seeds or suet. As a seabird, it is specialized in marine environments and does not adapt well to terrestrial feeding scenarios. If individuals are found near coastal regions or islands, it is usually in search of natural marine food sources or during breeding seasons, rather than seeking food from human-provided feeders. Bird feeding recommendations for shore or sea bird conservation should emphasize the preservation of their natural habitats and food sources rather than supplementing with alternatives suited to land birds.

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Black-vented Shearwater

Puffinus opisthomelas

How to recognise a black-vented shearwater?

General Appearance

The Black-vented Shearwater is a medium-sized seabird featuring a streamlined body adapted for dynamic soaring. Its upperparts are primarily dark brown to charcoal, complemented by paler underparts, showcasing a striking contrast. Characteristically, it has a distinctive black ventral area which extends down to its undertail coverts. The bird's wings are long and tapered with pale grayish-white shading underneath, a key field mark during flight. Its bill is short, light gray with a hook at the tip, and the legs and feet are pink, providing subtle hints of color against its darker plumage.

Male vs Female

The Black-vented Shearwater exhibits minimal sexual dimorphism, making it challenging to distinguish between males and females through visual observation alone. Both sexes share the same plumage coloration, size, and shape, and typically weigh about the same, a common trait among many shearwater species. Behavioral observations during mating seasons might offer some differentiation, yet visually, they are largely indistinguishable.

Juvenile

Juvenile Black-vented Shearwaters closely resemble adults but can be identified by their slightly duller and softer plumage, which aids in camouflaging them from predators during their early life stages. They lack the more defined contrast seen in adults, appearing more uniformly gray. As juveniles grow and undergo their first molt, their plumage becomes more defined and similar to that of mature adults. Recognizing young birds in the field requires a keen eye for these subtle shifts in coloration and texture.

Size

11.8 - 16.9 in/8.9 - 13.4 oz

Habitat

Primary habitat

The Black-vented Shearwater primarily inhabits the coastal regions of the Pacific Ocean, particularly around the Baja California Peninsula. They breed on offshore islands, favoring areas with sandy soils where they can dig burrows. The climate in these regions is typically arid to semi-arid, with warm temperatures and limited rainfall.

Additional range

Outside the breeding season, Black-vented Shearwaters can be found along the Californian coast up to central California. They demonstrate adaptability by inhabiting pelagic zones far from the shore, utilizing the open ocean for feeding and migration despite primarily being coastal birds.

Range Map

What do black-vented shearwaters like to eat?

Natural diet

The Black-vented Shearwater primarily feeds on fish and squid, diving from the surface to catch its prey. These birds are known for following fishing vessels to take advantage of discarded bycatch. They exhibit a varied and opportunistic diet, adjusting according to food availability in their environment. During breeding season, they may expand their diet to include krill and other small marine organisms to meet the increased energy demands.

Bird feeders

While Black-vented Shearwaters don't typically visit bird feeders due to their marine-dependent dietary habits, they can occasionally be drawn to areas where fishermen dispose of fish waste. They have evolved to thrive on oceanic food sources, and typical bird feeder offerings like seeds and suet are not appealing or suitable for them. However, if shore-based feeding is attempted, providing fish scraps or similar marine fare might momentarily catch their interest. Yet, it's essential to maintain their natural habits and not rely on human-provided food.

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Flesh-footed Shearwater

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Black-vented Shearwater

Flesh-footed Shearwater

Ardenna carneipes

General appearance

The Flesh-footed Shearwater is recognized by its uniform dark plumage, with feathers ranging from warm brown to almost black. Its flesh-colored legs and feet are striking against the dark body. The bill is pale, broad, and hooked at the tip, which helps distinguish it from similar species. The sheer size of this bird can also be notable, as it measures approximately 40-45 centimeters in length, with a wingspan of around 99-107 centimeters. The wings are long and slender, enabling it to glide effortlessly over the ocean.

Male vs female

There is very minimal sexual dimorphism in the Flesh-footed Shearwater, making it challenging to differentiate males from females based solely on appearance. Both sexes display the same dark plumage and flesh-colored feet. Their sizes are also comparable, with no significant variance in weight or wingspan that would aid identification.

Juvenile

Juvenile Flesh-footed Shearwaters closely resemble adult birds in coloration and size. However, juveniles can be identified by their slightly less worn feather quality, often appearing fresher and less glossy than those of adults. They might also venture closer to breeding colonies as they explore their surroundings, offering a clue to their age.

Size

15.7 - 18.9 in/22.9 - 28.6 oz

There's more to learn about Flesh-footed Shearwater

View full details

Black-vented Shearwater

Puffinus opisthomelas

General Appearance

The Black-vented Shearwater is a medium-sized seabird featuring a streamlined body adapted for dynamic soaring. Its upperparts are primarily dark brown to charcoal, complemented by paler underparts, showcasing a striking contrast. Characteristically, it has a distinctive black ventral area which extends down to its undertail coverts. The bird's wings are long and tapered with pale grayish-white shading underneath, a key field mark during flight. Its bill is short, light gray with a hook at the tip, and the legs and feet are pink, providing subtle hints of color against its darker plumage.

Male vs Female

The Black-vented Shearwater exhibits minimal sexual dimorphism, making it challenging to distinguish between males and females through visual observation alone. Both sexes share the same plumage coloration, size, and shape, and typically weigh about the same, a common trait among many shearwater species. Behavioral observations during mating seasons might offer some differentiation, yet visually, they are largely indistinguishable.

Juvenile

Juvenile Black-vented Shearwaters closely resemble adults but can be identified by their slightly duller and softer plumage, which aids in camouflaging them from predators during their early life stages. They lack the more defined contrast seen in adults, appearing more uniformly gray. As juveniles grow and undergo their first molt, their plumage becomes more defined and similar to that of mature adults. Recognizing young birds in the field requires a keen eye for these subtle shifts in coloration and texture.

Size

11.8 - 16.9 in/8.9 - 13.4 oz

There's more to learn about Black-vented Shearwater

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How to tell the Flesh-footed Shearwater from the Black-vented Shearwater

Visual differences

The Flesh-footed Shearwater (16-19 inches) is larger than the Black-vented Shearwater (12-17 inches). The Flesh-footed Shearwater features uniform dark brown to black plumage, pale, broad, hooked bill, and flesh-colored feet. In contrast, the Black-vented Shearwater showcases more varied plumage with gray tones and a black-tipped, slimmer bill. The Black-vented also typically has a lighter underbelly, with distinctive black vents, aiding in differentiation from the uniformly darker Flesh-footed.

Key differences and behavior

Flesh-footed Shearwaters and Black-vented Shearwaters exhibit key behavioral differences. Flesh-footed Shearwaters are globe-trotters, migrating between the Pacific and Indian Oceans, primarily in open waters, and exhibit kleptoparasitic tendencies by stealing food mid-air. They breed on islands off Australia and New Zealand, forming monogamous pairs with detailed courtship rituals. Their diet primarily includes fish and squid, caught via surface-seizing. Conversely, Black-vented Shearwaters are more localized to coastal Pacific regions, particularly around Baja California, often associated with fishing vessels to exploit bycatch. They are adept at "shear-water-ing" just above waves and breed in sandy or rocky island burrows. Their diet is opportunistic, focused on fish and squid, and, unlike Flesh-footed, they may include krill during breeding. Black-vented Shearwaters, being smaller (11.8-16.9 inches and weighing 8.9-13.4 ounces), contrast with the larger Flesh-footed Shearwaters (15.7-18.9 inches, 22.9-28.6 ounces).