How to identify the Scopoli's Shearwater

To correctly identify the Scopoli's Shearwater (Calonectris diomedea), check each of these features. Birds can be tricky: habit, habitat, and call often confirm a sighting that a single photo cannot.

Size at a glance

Length

45-56 cm

Wingspan

112-126 cm

Weight

500-1000 g

Physical features to check

1. 1

   Plumage

   Overall feather coloration and pattern.

   Adults have dark grey-brown upperparts, including the crown, nape, back, and upperwings. The underparts are pure white, contrasting sharply with the dark upperparts. The underwing is mostly white with a dark trailing edge and a dark patch at the carpal joint. The tail is dark.

2. 2

   Beak shape

   Shape and color of the bill: a key field mark.

   Large, stout, yellowish-horn colored bill with a dark tip and prominent tubular nostrils on top. The bill is hooked at the tip.

3. 3

   Eye color

   Iris color and any distinctive eye markings.

   Dark brown.

4. 4

   Leg color

   Leg and foot color.

   Pinkish-flesh colored legs and feet.

5. 5

   Distinguishing features

   Standout features that separate this species.

   Large size, pale bill with dark tip, dark upperparts contrasting with white underparts, and a distinctive underwing pattern (white with dark trailing edge and carpal patch). Its flight is characterized by long, stiff-winged glides.

6. 6

   Juvenile appearance

   How young birds differ from adults.

   Juveniles resemble adults but may have slightly fresher plumage and a less worn appearance. There are no significant differences in coloration or pattern.

7. 7

   Seasonal changes

   Plumage variation between breeding and non-breeding seasons.

   No significant seasonal changes in plumage. Plumage remains consistent throughout the year.

8. 8

   Sexual dimorphism

   How males and females differ.

   Males and females are monomorphic in plumage and size, with no discernible external differences.

Key field marks

• Size and Shape. Large shearwater with long, narrow wings held stiffly in flight. Appears robust.
• Plumage Pattern. Dark grey-brown upperparts (back, wings, head) contrasting sharply with pure white underparts. No dark belly patch or distinct cap.
• Bill Color. Prominent yellowish-horn colored bill with a dark tip. This is a key distinguishing feature from many other shearwaters.
• Underwing Pattern. Mostly white underwing with a dark trailing edge and a dark patch at the carpal joint (bend of the wing). The extent of the dark primary patch can help distinguish from Cory's Shearwater.
• Flight Style. Characteristic long, effortless glides on stiff wings, often banking steeply over waves, interspersed with short bursts of rapid wing beats.
• Vocalizations (at breeding colonies). Distinctive loud, wailing, and cackling calls ('a-WAA-oh') heard at night. This is diagnostic if heard in appropriate habitat.

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