Subject: WBC Pelagic 16 July
Date: Sat, 17 Jul 2004 14:52:48
From: John Arvin
If you like multiple excellent looks at Cory's Shearwater and Band-rumped Storm-Petrel yesterday was definitely your kind of day.
With only a decade or so of real pelagic trips under our belt, and at an average of 1.5-2 trips per year during that time,
we really don't know enough about the birdlife of the offshore Gulf of Mexico to say what a "typical" Texas coast pelagic trip is.
Each trip I have done has been different, and attempts to draw conclusions have been speculative at best.
Yesterday's trip was characterized by large numbers of Cory's Shearwater and Band-rumped Storm-Petrel
mostly in relatively shallow water (250+ ft). over the continental shelf. Another salient characteristic was
that most birds seen were sitting on the water in flocks of 5 or 6 individuals up to 30 or so.
This allowed for very close approach by the boat and the resulting views were outstanding.
Why birds were (1) over the continental shelf rather than out in true pelagic waters, and (2) mostly resting on the surface in flocks,
is impossible to say with existing knowledge. We did encounter a few other pelagic species as singles and not so close
(Masked Booby, Bridled and possibly Sooty Tern, and Leach's Storm-Petrel). Interestingly, preliminary examination
of my photos would seem to indicate that there was a second, unrecognized Leach's Storm-Petrel mixed in with
6-8 Band-rumped Storm-Petrels that continued to visit a piece of flotsam close by the boat.
In some frames I have 5 or 6 birds at once and one of these seems clearly to show the characteristics of Leach's Storm-Petrel though
we did not recognize it at the time. This is likely due to the fact that at that particular point there were mixed shearwaters
and storm-petrels in the number of 20-25 birds and it is pretty easy for one individual to get lost in the crowd.
Leach's Storm-Petrel is still on the Texas Bird Records Committee Review List (though I believe that continuing
coverage offshore will show that it is regular in small numbers and that only the infrequency of offshore trips
regulates the relatively small number of reports annual) so I will be submitting these photos for review by the TBRC.
There remains one pelagic trip this season, September 24th. We call this one The Albatross Trip because it was on
last year's September pelagic on almost the same date that we had spectacular looks at a very close Yellow-nosed Albatross.
Join us for another shot at unexpected seabirds and other marine organisms.
John Arvin
Subject: Species List for July 16th Pelagic trip
Date: Thu, 12 Aug 2004 08:45:47
From: John Arvin
In response to requests the complete list of bird species seen on the WBC July 16th Pelagic Trip follows below:
Pelagic Log July 16, 2004
Species: Total Number Water Depth(s)
Cory's Shearwater 71 118-400 ft.
Band-rumped Storm-Petrel 36 138-3000 t.
Leach's Storm-Petrel 1 3000 ft.
Masked Booby 1 155 ft.
Bridled Tern 1 3000 ft.
Tern sp. (probably Bridled) 1 3000 ft.
Royal Tern 1 (in pelagic waters; many in inshore waters) 3000 ft.
Notes: Many Black, Royal, Sandwich, and Least Terns, Laughing Gulls, and Brown Pelicans
were seen inshore as we approached and entered Brazos Santiago Pass into the Laguna Madre.
Post trip examination of photos indicated that birds identified as Band-rumped Storm-Petrels
were indeed all that species. What initially were thought to be characters indicating that one
or more might have been additional Leach's Storm-Petrels are attributable to molt and worn plumage.
All Cory's Shearwaters photographed show extensive primary molt which probably accounts for the fact
that most were resting on the water when encountered. In the absence of strong winds their molt
condition would require excessive energy expenditure to remain aloft for long periods.
Further indication of this is the fact that most of the birds would fly a minimum distance
when flushed and then resettle on the water.
Thanks to Brad McKinney for maintaining the sighting log through the trip.
