Leach's Storm-Petrel

Leach's Storm-Petrel is a small, sooty-brown seabird with a distinctly forked tail and a white rump patch that is often divided by a faint dark line down the center, a useful feature separating it from several similar species.

This species is almost entirely pelagic, spending nearly all of its life far from land over open ocean waters, coming ashore only to breed, and even then only under cover of complete darkness to avoid predatory gulls and owls that would otherwise easily catch such a small bird.

In flight, Leach's Storm-Petrel has an erratic, bounding, almost bat-like or nighthawk-like pattern, veering unpredictably from side to side, quite different from the more direct fluttering flight of some related storm-petrel species.

Key field marks

• Forked tail, unlike the squared tail of Wilson's Storm-Petrel
• White rump patch, often divided by a thin dark central line
• Erratic, bounding, bat-like flight pattern

Similar species

• Wilson's Storm-Petrel has a squared tail and steadier, more direct flight, along with conspicuous yellow feet webbing not typically visible on Leach's.
• Band-rumped Storm-Petrel has a broader, undivided white rump band and a more direct flight style compared to Leach's erratic movements.

Leach's Storm-Petrel breeds on remote offshore islands across the North Atlantic and North Pacific, including islands off eastern Canada, Iceland, and the Aleutian Islands, nesting in burrows dug into soft soil. Colonies are typically located on islands free of ground predators.

Outside the breeding season, the species disperses widely across open ocean waters, wintering at sea in tropical and subtropical latitudes far from any coastline.

Voice

At night around breeding burrows, Leach's Storm-Petrels give an eerie, chattering purr-like call along with a distinctive rhythmic "chuk-chuk" song, both used in pair communication and burrow defense.

Feeding

They feed on small crustaceans, fish, and squid picked from the ocean surface, often locating food by scent, using an acute sense of smell unusual among birds.

Nesting and breeding

Pairs nest in burrows dug into soft island soil, exchanging incubation duties in shifts that can last several days at a time while the off-duty parent forages far out at sea. Adults visit the colony strictly at night, and a single egg is laid per breeding attempt.