Leach's Storm-Petrel vs Cory's Shearwater

In short

Leach's Storm-Petrel and Cory's Shearwater are both seabirds but differ significantly in size and structure. Leach's Storm-Petrel is much smaller with a distinctive forked tail, while Cory's Shearwater is larger with a robust body and a straight tail. These differences are usually apparent even at a distance.

Identification tips

1. Size and Structure: Note the smaller size and forked tail of Leach's Storm-Petrel compared to the larger, straight-tailed Cory's Shearwater. 2. Flight Pattern: Look for the fluttery flight of Leach's Storm-Petrel versus the gliding flight of Cory's Shearwater. 3. Plumage: Check for the dark body with a paler rump on Leach's Storm-Petrel and the contrasting pale underbody of Cory's Shearwater. 4. Vocalization: Listen for Cory's Shearwater's wailing calls near breeding sites.

Size

Leach's Storm-Petrel is much smaller, about half the size of Cory's Shearwater.

Plumage

Leach's Storm-Petrel is mostly dark with a paler rump, whereas Cory's Shearwater has a pale underbody and a darker upper side.

Behaviour

Leach's Storm-Petrel often appears fluttery and erratic in flight, while Cory's Shearwater has a more direct and gliding flight pattern.

Habitat

Both species are pelagic but Cory's Shearwater is more likely to be seen closer to shore during breeding season.

Voice

Leach's Storm-Petrel is generally silent at sea, while Cory's Shearwater may emit a series of wailing calls, especially near breeding colonies.