Wilson's Storm-Petrel vs Townsend's Storm-Petrel

Wilson's Storm-Petrel

Oceanites oceanicus

How to recognise a wilson's storm-petrel?

General appearance

The Wilson's Storm-Petrel is a small, delicate seabird known for its dark plumage and contrasting pale rump. It possesses a sooty-black body with a lighter brown shade on the wings, and its undersides are similarly dark. A distinctive white band spans across the rump, providing a stark contrast to its otherwise dusky appearance. The tail is square-shaped, and the bird's slender legs extend well beyond the tail feathers as it hovers above the ocean surface. It measures approximately 16-18 cm in length and has a wingspan of about 38-42 cm.

Male vs female

Wilson's Storm-Petrels exhibit little to no sexual dimorphism, meaning that males and females appear almost identical in size and plumage coloration. There may be subtle differences in size or minor variations in feather tone, but these are not easily discernible in the field without close examination or during the breeding season.

Juvenile

Juvenile Wilson's Storm-Petrels resemble their adult counterparts closely but may be slightly duller in overall plumage coloration. The white band on their rump is less defined and may appear more off-white compared to the brilliant white seen in adults. As they mature, the clarity and contrast of their plumage increase, matching that of the adults. Over time, as juveniles reach full maturity, any variations in their appearance become less pronounced.

Size

5.9 - 7.5 in/1.2 - 1.7 oz

Habitat

Primary Habitat

The Wilson's Storm-Petrel primarily inhabits the offshore marine environments of the Southern Hemisphere. They are frequently found in the Southern Ocean, especially near the Antarctic Convergence. Their habitat includes cold, nutrient-rich waters where they spend much of their time feeding on plankton and small marine organisms, showcasing a preference for polar and subpolar climates.

Additional Range

While primarily southern, they occasionally venture into the Northern Hemisphere during the non-breeding season. Wilson's Storm-Petrels have been observed in temperate oceans worldwide, and some even forage near coastlines during migration. Their adaptability allows them to exploit a variety of marine habitats beyond their usual range.

Range Map

What do wilson's storm-petrels like to eat?

Natural Diet

Wilson's Storm-Petrel primarily sustains itself on a diet comprising small marine organisms. This seabird flies over the ocean, expertly dipping to catch plankton, crustaceans, and small fish close to the water's surface. They are particularly fond of tiny krill and copepods, which abound in the colder waters of their nesting areas. During feeding, they employ a characteristic "pattering" technique, appearing to dance on the water's surface as they pick at prey. Seasonal variations are noticeable as they follow the abundance of prey, often feeding near swarms of marine life, which vary depending on local ocean currents and temperatures.

Bird Feeders

Wilson's Storm-Petrel is not known to frequent bird feeders, and there are no typical offerings they would consume at such stations. These birds are strictly oceanic and rarely venture near land except for nesting purposes. They do not have a specific affinity for any non-marine feed items like seeds or suet. To encounter Wilson's Storm-Petrel, bird enthusiasts should consider oceanic expeditions or pelagic birdwatching tours rather than attempting to attract them with backyard feeders. Such excursions provide glimpses of these fascinating birds in their natural feeding habitats, dancing across the waves in search of their oceanic diet.

There's more to learn about Wilson's Storm-Petrel

View full details

Townsend's Storm-Petrel

Hydrobates socorroensis

How to recognise a townsend's storm-petrel?

Townsend's Storm-Petrel Recognition Guide

1. General appearance: The Townsend's Storm-Petrel exhibits a compact body shape typical of the storm-petrels. Its plumage is predominantly sooty brown with a slightly paler rump and upper tail coverts. The wings are long and pointed, aiding in its graceful, fluttering flight often close to the water. The tail is squared at the tip. The beak is black and relatively short, while the feet are also black, with webbing between the toes. 2. Male vs female: Both male and female Townsend's Storm-Petrels are visually similar and do not exhibit significant sexual dimorphism. They share the same plumage pattern and coloration, making it challenging to distinguish between sexes based solely on physical traits in the field. 3. Juvenile: Juveniles closely resemble adults but may have slightly fresher and less worn plumage upon fledging. Juveniles exhibit the same sooty brown coloration and similar wing and tail shapes as the adults. As they mature, their plumage will gradually acquire a more consistent sheen, aligning closely with that of fully-grown birds. Behavioral differences, rather than plumage, are often more telling when identifying juveniles, as they can appear less experienced in flight techniques compared to adult birds.

Size

7.9 - 9.1 in/0.7 - 0.9 oz

Habitat

Primary habitat

Townsend's Storm-Petrel thrives primarily in the northeastern Pacific Ocean, closely surrounding the Baja California Peninsula and islands such as Socorro Island. They prefer open ocean habitats, ranging from temperate to tropical climates where they often remain offshore, feeding in rich upwelling zones that provide an abundant supply of plankton and small marine creatures.

Additional range

Outside of their main habitat, Townsend's Storm-Petrels may infrequently venture further out into the broader Pacific Ocean as far as the coasts of Central America. Although less common, they have been noted to navigate unexpected environments such as those with colder ocean currents, displaying considerable adaptability to fluctuating maritime conditions.

Range Map

What do townsend's storm-petrels like to eat?

Natural diet

The Townsend's Storm-Petrel primarily feeds on small marine organisms. Its diet consists mainly of planktonic crustaceans, such as krill, and various small fish that are abundant in its oceanic habitat. This bird often captures prey close to the water's surface, dipping down while gliding on its wings. Occasionally, it will also consume squid when available. During the breeding season, when food abundance can fluctuate, Townsend's Storm-Petrels might adjust their foraging techniques to ensure enough intake for themselves and their young.

Bird feeders

The Townsend's Storm-Petrel does not typically visit bird feeders. Due to its pelagic lifestyle, which keeps it far from terrestrial environments where feeders are found, it rarely encounters these food sources. However, if offered an opportunity at a coastal area where bird feeders might be present, it might show interest in foods resembling its natural diet, like small fish or krill-based options. Nonetheless, providing a natural habitat with minimal human interaction enhances the conservation of their feeding patterns and supports their dietary needs.

There's more to learn about Townsend's Storm-Petrel

View full details

Wilson's Storm-Petrel

Tap To compare

Townsend's Storm-Petrel

Wilson's Storm-Petrel

Oceanites oceanicus

General appearance

The Wilson's Storm-Petrel is a small, delicate seabird known for its dark plumage and contrasting pale rump. It possesses a sooty-black body with a lighter brown shade on the wings, and its undersides are similarly dark. A distinctive white band spans across the rump, providing a stark contrast to its otherwise dusky appearance. The tail is square-shaped, and the bird's slender legs extend well beyond the tail feathers as it hovers above the ocean surface. It measures approximately 16-18 cm in length and has a wingspan of about 38-42 cm.

Male vs female

Wilson's Storm-Petrels exhibit little to no sexual dimorphism, meaning that males and females appear almost identical in size and plumage coloration. There may be subtle differences in size or minor variations in feather tone, but these are not easily discernible in the field without close examination or during the breeding season.

Juvenile

Juvenile Wilson's Storm-Petrels resemble their adult counterparts closely but may be slightly duller in overall plumage coloration. The white band on their rump is less defined and may appear more off-white compared to the brilliant white seen in adults. As they mature, the clarity and contrast of their plumage increase, matching that of the adults. Over time, as juveniles reach full maturity, any variations in their appearance become less pronounced.

Size

5.9 - 7.5 in/1.2 - 1.7 oz

There's more to learn about Wilson's Storm-Petrel

View full details

Townsend's Storm-Petrel

Hydrobates socorroensis

Townsend's Storm-Petrel Recognition Guide

1. General appearance: The Townsend's Storm-Petrel exhibits a compact body shape typical of the storm-petrels. Its plumage is predominantly sooty brown with a slightly paler rump and upper tail coverts. The wings are long and pointed, aiding in its graceful, fluttering flight often close to the water. The tail is squared at the tip. The beak is black and relatively short, while the feet are also black, with webbing between the toes. 2. Male vs female: Both male and female Townsend's Storm-Petrels are visually similar and do not exhibit significant sexual dimorphism. They share the same plumage pattern and coloration, making it challenging to distinguish between sexes based solely on physical traits in the field. 3. Juvenile: Juveniles closely resemble adults but may have slightly fresher and less worn plumage upon fledging. Juveniles exhibit the same sooty brown coloration and similar wing and tail shapes as the adults. As they mature, their plumage will gradually acquire a more consistent sheen, aligning closely with that of fully-grown birds. Behavioral differences, rather than plumage, are often more telling when identifying juveniles, as they can appear less experienced in flight techniques compared to adult birds.

Size

7.9 - 9.1 in/0.7 - 0.9 oz

There's more to learn about Townsend's Storm-Petrel

View full details

How to tell the Wilson's Storm-Petrel from the Townsend's Storm-Petrel

Visual differences

Wilson's Storm-Petrel is smaller (6.3-7.5 inches in length), with a square tail and a distinctive white rump band contrasting its sooty-black plumage. In contrast, Townsend's Storm-Petrel is slightly larger (7.9-9.1 inches in length) and is characterized by more uniform dark plumage without a pronounced white rump. Wilson's has slender legs extending beyond the tail during flight, while Townsend's exhibits less leg extension. Both have small, sharp beaks, but Wilson's is known for its distinctive "pattering" flight behavior over water, unlike Townsend's more gliding flight.

Key differences and behavior

Wilson's Storm-Petrel and Townsend's Storm-Petrel exhibit distinct behavioral and ecological strategies. Wilson's Storm-Petrel, known for its "dancing" on water, feeds on plankton using a pattering technique and thrives in the Southern Hemisphere's cold, nutrient-rich waters. It breeds in Antarctica and migrates globally. In contrast, the nocturnal Townsend's Storm-Petrel glides over the ocean, feeding on fish and squid in the northeastern Pacific, notably near Baja California. Both species nest in rocky crevices, but Wilson's Storm-Petrel prefers isolated coastal zones, whereas Townsend's return to the same Pacific nesting sites annually. Wilson's engages in day courtship, while Townsend's is active at night. Both are monogamous, sharing incubation duties.