Bermuda Petrel Pterodroma cahow
Gulf Stream off Oregon Inlet, North Carolina
2 June 2000
Joseph Morlan
Robbie Fischer and I were passengers
aboard the Country Girl on one of Brian Patteson's
pelagic trips. The voyage had been quite successful with excellent viewing conditions and relatively calm seas.
By about 2pm, most of the regular species were in high numbers but no significant rarities had been seen. The skipper
announced that the boat would be returning to port soon. Suddenly whales were announced over the public address
system. I was on the right forward side of the boat where we had excellent views of at least two Cuvier's Beaked
Whales. While enjoying these small whales, Peter Fraser from Cornwall, England called out, "What's this?"
He then started choking out the words "Cahow!" I got on the bird immediately as it headed right in toward
the boat, banking close down the right side, circling the stern and flying up the left side giving everybody excellent
views of this rarely seen bird. It made another pass near the boat as Brian Patteson announced "Bermuda Petrel"
before the bird headed forward and away.
The "Country Girl" is an unusually fast boat. The skipper gunned the engines, and ran the boat full
bore, overtaking the Bermuda Petrel
at least three times. He tried to adjust the speed to keep the bird with the boat, but the petrel slowed and we
past the bird several times. Eventually the bird got away from us, but not until everybody on board had very satisfying
views.
The following is a description of the bird.
A medium-sized light Pterodroma superficially similar to Black-capped Petrel (Pterodroma hasitata) many of which had been seen during the trip. It was slightly smaller than Black-capped Petrel, with a noticeably smaller bill. When Black-capped Petrels came in close to the boat, I was impressed by their massive sculptured bill. I specifically looked at the Bermuda Petrel's bill and felt it was much less deep and smaller overall.
The most obvious difference between the Bermuda Petrel and the Black-capped, was the head pattern. Both species showed a white forehead, but on the Black-capped Petrels, the dark cap came down through the eye and then receded on the side of the nape, usually forming a wide white collar around the back of the head. On the Bermuda Petrel, the black cap blended with the dark gray of the back and nape coming down on the side of the breast in a uniform straight line before curving up to meet the mantle. Thus the head pattern recalled that of Dark-rumped Petrel (Pterodroma phaeopygia) more than Black-capped.
The upperparts were dark with white spotting visible at the bases of the secondaries and some primaries. These were pale feather shafts made visible because many of the greater wing coverts had been molted and were missing. Most of the Black-capped Petrels showed a similar pattern of heavy molt.
The rump was mostly dark, but the uppertail coverts were white forming an indistinct, narrow band of mottled white. This band blended gradually with the long dark gray tail and did not contrast sharply as in the Black-capped Petrels.
The underparts were white, with a broad black carpal bar extending along the leading edge of the outer underwing and angling back toward the axillaries. I also got the impression of some dusky flecking on the secondaries as the bird banked toward us. The underwing was similar to that of Black-capped Petrel but seemed overall more heavily marked and darker.
The bird flew in the graceful style of Black-capped Petrel, gliding up on bowed wings and seldom flapping. In discussion with others, most felt that the bird was shorter winged and longer tailed than Black-capped Petrel, but this was a subtle distinction and not particularly obvious.
Discussion
The Bermuda Petrel is one of North America's rarest birds with only about 200 individuals believed to reside on islets off Bermuda. The 7th edition of the AOU Checklist (1998) states that there are no confirmed records away from the breeding grounds, but "sightings have been reported off North Carolina." The species was recently added to the American Birding Association Checklist (Birding 31:518-524, 1999) based on individuals photographed off North Carolina 26 May 1996, 29 May 1998 (Field Notes 52:408, 1998) and 16 August 1999. The official North Carolina Bird Checklist indicates that there is one accepted record of Bermuda Petrel with two more pending.
Additional information on Bermuda Petrel's status is provided by Birdlife International and at Angus Wilson's site. The standard reference on identification and distribution is
Wingate, D. B., Hass, T., Brinkley, E. S., and Patteson, J. B. (1998) Identification of Bermuda Petrel. Birding 30: p18-36.
A copy of this paper was available aboard the boat and was instrumental in convincing the skeptics among us that we had really seen this almost mythical bird.
Several excellent photographs taken in past years have been posted at Brian Patteson's site. A Bermuda Petrel was also seen well and photographed on May 26th and seen briefly on May 27th. An account of these trips has been posted here. Comparing the molt pattern evident in the photos by Martin Myers, posted above with those posted by Patteson show that our bird was almost certainly the same individual. Another Bermuda Petrel was seen June 3rd out of Manteo by the Focus on Nature tour, but no photos were obtained. It was said to be in fresh plumage, and thus definitely a different bird from the earlier sightings (Paul Guris pers.comm).
Martin Meyers has posted a more detailed account of our trip on Birdchat. Additional commentary on identification by Macklin Smith and Gail Mackiernan can be found there and very helpful information on variation in Black-capped Petrel has been posted by Todd McGrath.