Hawaiian Petrel vs Bermuda Petrel

Hawaiian Petrel

Pterodroma sandwichensis

How to recognise a hawaiian petrel?

General Appearance

The Hawaiian Petrel is a striking seabird known for its dark gray or almost black upperparts and contrasting white underparts. Its wings are long and pointed, aiding in its efficient flight over the ocean. Notable features include a white forehead and face, with a distinct dark gray stripe running through each eye. The bill is slender and black, curved at the tip. Its tail is relatively short and fan-shaped, often visible against the sky as the bird glides high above the waves.

Male vs Female

There are no significant differences in the appearance of male and female Hawaiian Petrels. Both sexes possess similar plumage and physical traits, making gender identification in the field nearly impossible without closer inspection or genetic analysis. This lack of sexual dimorphism suggests that both males and females share similar roles in nesting and caring for young.

Juvenile

Juvenile Hawaiian Petrels resemble adults but with some subtle features that differentiate them. Young birds often have slightly duller plumage and may exhibit a less refined bill structure. The gray on their upperparts lacks the same depth of color seen in mature birds. As they age, their feathers will achieve the darker shades and distinctive markings that characterize adult petrels. In their first year, juveniles undergo molt as they transition to mature plumage, completing their transformation by the end of their first year.

Size

15.7 - 18.1 in/13.1 - 21.2 oz

Habitat

Hawaiian Petrel Habitat

Primary habitat: The Hawaiian Petrel primarily inhabits the mountainous regions on the Hawaiian Islands, such as Maui and the Big Island. These seabirds prefer nesting in burrows on steep slopes, within native forests that offer protective cover from predators. They range primarily across open ocean waters, feeding during their vast marine journeys. Additional range: While primarily marine, Hawaiian Petrels have also been spotted in lowland coastal areas when resting during migrations. Their adaptability allows them to feed over deep ocean waters and occasionally nest on isolated inshore and offshore islands.

Range Map

What do hawaiian petrels like to eat?

Natural diet

The Hawaiian Petrel predominantly feeds on a diet consisting of oceanic prey. These seabirds primarily consume squid and small fish, which provide the necessary nutrients for their energetic lifestyle. During the nesting season, they embark on extensive foraging trips, traveling vast distances to hunt for food. They often capture their prey at night, utilizing a keen sense of smell and sight. While their diet does fluctuate slightly during breeding, squid remains an essential component throughout the year. During warmer months, when squid populations are abundant, their consumption increases.

Bird feeders

The Hawaiian Petrel is not known to visit bird feeders, as its feeding habits are closely tied to marine environments. These seabirds are not attracted to the typical offerings found in backyard settings, such as seeds or suet. Their diet relies heavily on open ocean resources, making them unlikely to benefit from typical bird feeder provisions. As such, there are no specific feeder recommendations or preferences for the Hawaiian Petrel, given its specialized foraging behavior and dietary requirements.

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Bermuda Petrel

Pterodroma cahow

Also known as: Cahow

How to recognise a bermuda petrel?

General appearance

The Bermuda Petrel, also known as the Cahow, exhibits a graceful maritime silhouette with a distinctive coloration that aids in identification. Its plumage is primarily dark gray on the wings and back, contrasting with the predominantly white underparts, creating a striking appearance. The face features a white forehead that connects to a collar of darker feathers around the nape, while the bill is slender and black, adapted for catching prey in its oceanic habitat.

Male vs female

In terms of physical appearance, there is minimal sexual dimorphism between male and female Bermuda Petrels. Both sexes share similar plumage patterns, size, and coloration, making it challenging to distinguish between them in the wild based solely on appearance. Behavioral observations during breeding seasons may offer more accurate ways to differentiate them as both sexes contribute equally to incubation and chick-rearing.

Juvenile

Juvenile Bermuda Petrels bear a close resemblance to adults but can be distinguished by slightly duller and more uniform plumage. The gray coloration on their wings and back lacks the subtle iridescence seen in adults, and their facial features may appear more subdued. Over time, as juveniles mature, they molt into the sharper, more contrasty plumage of adulthood. Despite these differences, distinguishing them at sea requires careful observation due to the similarity in their size and overall appearance.

Size

15.7 in/4.0 - 7.0 oz

Habitat

Primary Habitat

The Bermuda Petrel, also known as the Cahow, primarily resides on small rocky islets in the Bermuda archipelago. These regions offer the ideal nesting grounds, characterized by dense vegetation and a subtropical climate. The birds prefer secluded, undisturbed areas with easy access to the ocean for feeding, typically within the North Atlantic's moderate temperatures.

Additional Range

Though the Bermuda Petrel's range is predominantly localized, they occasionally roam to unexpected territories during their foraging expeditions. These seabirds adapt well to open ocean environments, sometimes venturing further into temperate waters beyond their primary nesting sites. Their adaptability ensures survival across varied marine climates.

Range Map

What do bermuda petrels like to eat?

Natural diet

The Bermuda Petrel, also known as the Cahow, primarily feeds on a diet composed of small fish, squid, and crustaceans. As a pelagic bird, it sources its food from the open ocean. The consumption of these marine creatures provides the necessary nutrients for their survival. Seasonal variations affect their diet as certain marine species become more abundant at different times of the year. During spring and summer, they might find a larger quantity of prey as fish and squid populations tend to be more accessible.

Bird feeders

Bermuda Petrels do not typically frequent bird feeders because of their pelagic lifestyle. They spend the majority of their time far from land, navigating vast expanses of ocean to seek food. As such, traditional bird feeder setups with seed mixes, suet, or fruits do not cater to their specific dietary needs. Additionally, the Bermuda Petrel relies on live marine prey and does not consume the typical bird feeder offerings that attract terrestrial or land-based bird species. Hence, feeding them at bird feeders is neither feasible nor necessary to support their natural diet.

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Hawaiian Petrel

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Bermuda Petrel

Hawaiian Petrel

Pterodroma sandwichensis

General Appearance

The Hawaiian Petrel is a striking seabird known for its dark gray or almost black upperparts and contrasting white underparts. Its wings are long and pointed, aiding in its efficient flight over the ocean. Notable features include a white forehead and face, with a distinct dark gray stripe running through each eye. The bill is slender and black, curved at the tip. Its tail is relatively short and fan-shaped, often visible against the sky as the bird glides high above the waves.

Male vs Female

There are no significant differences in the appearance of male and female Hawaiian Petrels. Both sexes possess similar plumage and physical traits, making gender identification in the field nearly impossible without closer inspection or genetic analysis. This lack of sexual dimorphism suggests that both males and females share similar roles in nesting and caring for young.

Juvenile

Juvenile Hawaiian Petrels resemble adults but with some subtle features that differentiate them. Young birds often have slightly duller plumage and may exhibit a less refined bill structure. The gray on their upperparts lacks the same depth of color seen in mature birds. As they age, their feathers will achieve the darker shades and distinctive markings that characterize adult petrels. In their first year, juveniles undergo molt as they transition to mature plumage, completing their transformation by the end of their first year.

Size

15.7 - 18.1 in/13.1 - 21.2 oz

There's more to learn about Hawaiian Petrel

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Bermuda Petrel

Pterodroma cahow

Also known as: Cahow

General appearance

The Bermuda Petrel, also known as the Cahow, exhibits a graceful maritime silhouette with a distinctive coloration that aids in identification. Its plumage is primarily dark gray on the wings and back, contrasting with the predominantly white underparts, creating a striking appearance. The face features a white forehead that connects to a collar of darker feathers around the nape, while the bill is slender and black, adapted for catching prey in its oceanic habitat.

Male vs female

In terms of physical appearance, there is minimal sexual dimorphism between male and female Bermuda Petrels. Both sexes share similar plumage patterns, size, and coloration, making it challenging to distinguish between them in the wild based solely on appearance. Behavioral observations during breeding seasons may offer more accurate ways to differentiate them as both sexes contribute equally to incubation and chick-rearing.

Juvenile

Juvenile Bermuda Petrels bear a close resemblance to adults but can be distinguished by slightly duller and more uniform plumage. The gray coloration on their wings and back lacks the subtle iridescence seen in adults, and their facial features may appear more subdued. Over time, as juveniles mature, they molt into the sharper, more contrasty plumage of adulthood. Despite these differences, distinguishing them at sea requires careful observation due to the similarity in their size and overall appearance.

Size

15.7 in/4.0 - 7.0 oz

There's more to learn about Bermuda Petrel

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How to tell the Hawaiian Petrel from the Bermuda Petrel

Visual differences

The Hawaiian Petrel is larger, weighing 370-600g with a length of 15.7-18.1 inches, compared to the Bermuda Petrel at 113-198g and 15.7 inches. Hawaiian Petrels have darker gray upperparts and lack the white forehead and nape contrast of Bermuda Petrels. The Bermuda Petrel features a slender, black bill suited for its prey, while Hawaiian Petrel's juveniles have a slightly less refined bill. Both share similar underpart coloration and pelagic nature, but these key differences aid identification.

Key differences and behavior

The Hawaiian Petrel and Bermuda Petrel, while similar in their marine habitats, exhibit notable behavioral distinctions. Hawaiian Petrels are night navigators, traveling vast Pacific distances to hunt primarily squid, while Bermuda Petrels venture across the North Atlantic, feeding on small fish, squid, and crustaceans. In nesting, Hawaiian Petrels use burrows on the steep volcanic slopes of Hawaii, coordinating through vocal duets and aerial displays. Conversely, Bermuda Petrels nest in rocky islets with natural crevices, forming long-term bonds with synchronized flights and preening. Hawaiian Petrels weigh notably more (up to 21 oz) compared to Bermuda Petrels (7 oz), influencing their flight dynamics and environmental roles.