First North American Record of Black-bellied Strom-petrel (<i>fregetta Tropica</i>)

This paper documents the first North American record of Black-bellied Storm-Petrel (Fregetta tropica), a single bird photographed off North Carolina 31 May 2004, provides context for this record in the North Atlantic Ocean, and summarizes field identification of Fregetta storm-petrels.FIELD ENCOUNTER On 31 May 2004, the authors and 16 other observers aboard the sport-fishing boat Country Girl observed a Black-bellied Storm-Petrel (Fregetta tropica) approximately 77 km southeast of Oregon Inlet, North Carolina.Ihe bird was observed from 1420 to 1450 EDT, at distances as close as 30 m while it flew and fed amongst 135 Wilson's (Oceanires oceanicus), five keachg (Oceanodroma leucorhoa), and two Band-rumped (Oceanodroma castro) Storm-Petrels over a slick of fish oil we had set oul to attract birds.Ihe location of the initial discovery was approximately 35 ø ll.5' N, 74 ø 47.5' W (LORAN-C 26777, 40511).Ihe water depth here is approximately 1566 m (870 fathoms; 5ll0 feet).Ihe seawater temperature in the vicinity of the observation was approximately 72 ø E Seawater of this temperature and color is usually called "green water" by local fishermen, in contrast to the "blue water" of the nearby Gulf Stream, which is warmer and clearer.Ihe water in this general area is often a mixture of warmer Gulf Stream and cooler Labrador Seawater Current water.Ihe Black-belhed Storm-Petrel was first noted by the boats mate, John Gallop.Ihe bird stood out among the surrounding Wilsong Storm-Petrels due to its stockter build, dark hood, white belly, black undertail coverts, and white underwing coverts.At the time of observation, we identified this individual as a White-bellied Storm-Petrel (E grailaria), as we were not able to discern the black belly stripe.Fortunately, several on board managed to obtain videotape footage and still photographs (Figures 1-9), some of which clearly >ow the ventral stripe (e.g., Figures 3, 4, 8) and thus leave no doubt as to the identification.Although the blackish ventral • stripe would seem an obvious field mark, it was not clearly observed, probably owing to unfavorable angles of observation and the bird's low flight profile.Moreover, when the bird was observed in profile, the •, stripe probably "disappeared" against the dark seawater, leaving the impression of a white belly (Figure 9; see comparative illustration by P. Burke, inJaramillo 2003).Several observers who thought they saw this stripe in the field discounted it as shadow while the bird was under observation.Our collective impressions of the bird in the field, as well as from photographs and videotape studied subsequently, are digested below.The marks described are clearly discernable in Figures 1-9."Proportions and body rather stocky compared to Wilsong Storm-Petrel.In slow feeding flight, wing shape appeared broad, not particularly long, with a gently rounded carpal joint.In direct flight, wing appeared longer than the accompanying Wilson's but still showed a rounded carpal angle.Feet appeared black, extending beyond tail.Mantle, scapulars, and back dark charcoal graybrown.Flight feathers black.Upperwing coverts dark gray-brown, with paler tanbrown tips to greater coverts forming a distinct pale carpal bar.Median upperwing coverts with much narrower pale tips, apparently indicating fresh plumage.Uppertail coverts white.Iail blackish.Figures 1, 2. Black-bollJed Storm-Petrel, off Oregon Inlet, North Carolina 31 May 2004 (all figo res).The dotsum of the storm-petrel showed blackish flight feathers that contrasted with brownish upperwing coverts, a thin paler brown carpal bar formed by the tips of the greater uppersecondary coverts, white uppertail coverts, a blackish tail, and feet that projected well beyond the tail.Most sources note that the feet of Blackbdlied project about one centimeter beyond the tail but do not project beyond the tail in White-bellied.Photographs byRick Wiltraut.

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