Thursday, September 24, 2009
Sept 18-20 Pacific pelagic gets new species for Costa Rica - Tahiti Petrel (Pseudobulweria rostrata)
1. Tahiti Petrel (Pseudobulweria rostrata). One of five individuals seen September 18-19 off Pacific coast of Costa Rica. Surprisingly the species does not appear on the main list of the AOU for North America because of possible confusion with Phoenix Petrel (Pterodroma alba) although it has been reported regularly by researchers working in the eastern tropical Pacific and is included in Howell and Webb's Guide to the Birds of Mexico. This photo shows the long straight wing, and long thin tail profile typical of the species. Photo by Noel Ureña.
2. Tahiti Petrel (Pseudobulweria rostrata). The first individual was seen only 33 km south of the tip of the Nicoya peninsula, well within the range of a one day pelagic trip out of Los Sueños or Quepos. Photo by Noel Ureña.
3. Tahiti Petrel (Pseudobulweria rostrata). Distinctive large bill, dark unpatterned underwing, long thin tail, and grayish rump are all marks that help distinguish this species from Phoenix Petrel (Pterodroma alba). Photo by Noel Ureña.
4. Markham's Storm-Petrel (Oceanodroma markhami) - another rare species we found on this trip. Two individuals were identified. Others were possible but couldn't be seen well enough to distinguish them from the more common and very similar Black Storm-Petrel. Photo by Noel Ureña.
5. Parkinson's Petrel (Procellaria parkinsoni) - only one bird was observed when it came to our chum along with a handful of Wilson's Storm-Petrels and a Pink-footed Shearwater at the end of the day on Sept 19th. Photo by Noel Ureña.
6. White Tern (Gygis alba) - again, only one individual was seen, this one just before sunset on the first day, Sept. 18th about 150 km from shore. Photo by Noel Ureña.
7. Red-footed Booby (Sula sula) - Dark morph adult, the form typically found in Costa Rican waters. We've had several trips where the last bird of the day is a Red-footed Booby that tries to land on the mast for the night. Photo by Noel Ureña.
8. Sabine's Gull (Xema sabini) - a common migrant out at sea this time of year. Most, like this bird, were almost molted into their winter plumage. We found a large flock attending a trawler that was hauling in it's nets out in the Gulf of Nicoya on Sept. 20th. Among the hundreds of Brown Boobies (Sula leucogaster) also in attendance we managed to spot one Blue-footed Booby (Sula nebouxii). Photo by Noel Ureña.
9. Wedge-rumped Storm Petrel (Oceanodroma tethys) - by far the most common species of storm-petrel this time of year. Photo by Noel Ureña.
10. Audubon's Shearwater (Puffinus lherminieri) - always a regular though usually in smaller numbers than the other regular member of the genus in Pacific Costa Rican waters, the Wedge-tailed Shearwater (P. pacificus). Audubon's Shearwater complex is split by some into several species, the one found here on the Pacific side would be the Galapagos Shearwater (P. subalaris). Caribbean birds would still be Audubon's. We also saw one Manx/Townsend's Shearwater (P. puffinus/auricularis) but were unable to see it well enough, or get photos, to tell which species it might have been. Photo by Noel Ureña.
11. Paul Murgatroyd with American Redstart that came aboard the boat out in the middle of the Gulf of Nicoya. It stayed with us for about an hour and finally headed out on its own for land shortly before we reached Playa Herradura. At first timid, it soon became bold enough to perch on anyone's head or outstretched arm. Thanks to Paul for sponsoring yet another wonderful journey aboard the Floating Bear and for his contributions towards furthering our knowledge of Costa Rica's pelagic birds. Photo by Noel Ureña.
Here is the at sea list for the three day trip - September 18-20, 2009.
5 - Tahiti Petrel (Pseudobulweria rostrata)
13 - unidentified petrel sp.
1 - Parkinson's Petrel (Procellaria parkinsoni)
3 - Pink-footed Shearwater (Puffinus pacificus)
74 - Wedge-tailed Shearwater (P. pacificus)
14 - Audubon's Shearwater (P. lherminieri)
5 - unidentified shearwater sp.
9 - Wilson's Storm-Petrel (Oceanites oceanicus)
12 - Leach's Storm-Petrel (Oceanodroma leucorhoa)
(Leach's rump color: 7 white, 4 dark, 1 intermediate)
2 - Band-rumped Storm-Petrel (O. castro)
59 - Wedge-rumped Storm-Petrel (O. tethys)
12 - Black Storm-Petrel (O. melania)
2 - Markham's Storm-Petrel (O. markhami)
1 - Least Storm-Petrel (O. microsoma)
33 - unidentified Storm-Petrel with white rump
3 - unidentified Storm-Petrel with dark rump
9 - Red-billed Tropicbird (Phaethon aethereus)
1 - Masked Booby (Sula dactylatra)
4 - Masked/Nazca Booby (S. dactylatra/granti)
1 - Blue-footed Booby (S. nebouxii)
606 - Brown Booby (S. leucogaster)
10 - Red-footed Booby (S. sula)
246 - Brown Pelican (Pelecanus occidentalis)
329 - Magnificent Frigatebird (Fregata magnificens)
1 - Semipalmated Plover (Charadrius semipalmatus)
19 - unknown shorebird
250 - Red-necked Phalarope (Phalaropus lobatus)
5 - Red Phalarope (P. fulicarius)
59 - Sabine's Gul (Xema sabini)
1 - Franklin’s Gull (Leucophaeus pipixcan)
4 - Brown Noddy (Anous stolidus)
1 - White Tern (Gygis alba)
9 - Bridled Tern (Onychoprion anaethetus)
41 - Black Tern (Chlidonias niger)
1 - Royal Tern (Thalasseus maximus)
1 - Sandwich Tern (T. sandvicensis)
1 - Elegant Tern (T. elegans)
1 - Common/Arctic Tern (Sterna hirundo/paradisaea)
3 - Pomarine Jaeger (Stercorarius pomarinus)
6 - Parasitic Jaeger (S. parasiticus)
1 - Long-tailed Jaeger (S. longicaudus)
8 - unidentified jaeger sp.
7 - Bank Swallow (Riparia riparia)
19 - Cliff Swallow (Petrochelidon pyrrhonota)
10 - Barn Swallow (Hirundo rustica)
9 - unidentified swallow sp.
1 - American Redstart (Setophaga ruticilla)