JOUANIN’S PETREL Bulweria fallax

JOUANIN’S PETREL Bulweria fallax

L 30–32 cm, WS 76–83 cm.

IDENTIFICATION 

Vagrant from NW Indian Ocean (breeding grounds unknown but perhaps on islands off Arabian Peninsula). Medium-sized petrel that is similar to Bulwer’s in character, but with quicker, more powerful, flight action. Has steady flight action with tern-like wingbeats, intermittently banking away sharply to glide along wave troughs before rising and continuing once more with steady wingbeats. In very calm conditions beats wings almost continually, recalling a small skua but in windier conditions makes high sweeping arcs interspersed with short series of rapid wingbeats (recalling Pterodroma). Holds wings slightly forward and bowed, like Bulwer’s. Species distinguished from Bulwer’s by larger size, rather different flight action, proportionately heavier head and thicker bill (which create heavier look overall), and characteristic ‘step’ in outline of long tail (with central feathers projecting).

Tail appears less slender. Typically lacks pale band across upperwing coverts (but this often impossible to see on Bulwer’s, and some worn Jouanin’s show a pale band). At close range small pale area around base of bill and shortness of outer tail feathers may be noticeable. Distinctions from Swinhoe’s Storm-petrel as for
Bulwer’s. Long tail, all-dark underwing, rather thick bill (usually held at a distinctly angled downwards) and different flight action separates Jouanin’s from larger Sooty Shearwater and from vagrant Flesh-footed or dark morph Wedge-tailed Shearwaters. Head of latter is noticeably slimmer than in Jouanin’s.

VOICE 

Silent at sea.
 

STATUS/HABITAT 

Vagrant (Italy). Pelagic away from breeding colonies.