Thursday, October 28, 2010

Pelagic Caribbean seabirds found in oil spill response

The US Fish and Wildlife Service has made the summary data available for seabirds that were found in the oil spill recovery. The report is available here:

Below is a tedious listing of the dead birds found. The interesting thing is that any of the pelagics were found at all. The recovery rate for a bird oiled 150 km out at sea and subject to burning and pick up in oil collecting boats could not be better than 3% and is likely less than 1%.

We should have been out there in a boat dropping marked bird carcasses but how were we supposed to know.

Especially for Masked Boobies and Audubon's Shearwaters, we should multiply their numbers by a factor of between 33 and 100 to get a minimum estimate of the number of actual dead birds. For the nearshore species, recovery probably mirrored that of Alaska during the Valdez spill where they estimated recovery at about 10%.

The other outstanding questions are where exactly were each of these birds found and did the birds that were found alive survive. I can't imagine a situation where you would catch one of these things alive unless it was injured or a young, starving fledgeling. One should be able to detect if it is a young of the year bird from date it was found, plumage, molt, and wing proportions, at least for a shearwater, but most of these carcasses may have already been destroyed.

For Caribbean seabirds, the results are as follows:

Bermuda Petrel and Black-capped Petrel - none found

Audubon's Shearwater: 3 total birds. One oiled, dead bird. One dead bird with no visible oil. One live bird with no visible oil. There were also 4 dead, unidentified shearwaters. Three had no visible oil. For the other, the Oiling status was not reported (?).

White-tailed and Red-billed Tropicbirds: none found

Brown Pelicans - 738 were found. 290 had no signs of oil (187 dead, 103 alive). 259 were oiled (111 dead and 148 alive). 189 were dead but oiling status was not reported. We don't have the data, but I assume most if not all were of the North American subspecies (Pelicanus occidentalis carolinensis) rather than the Caribbean subspecies (P. o. occidentalis).

Masked Boobies: Of the 3 breeding boobies in the region, only Masked Boobies were found. There were 8 total birds. 4 were dead and had no outward oil signs. 2 were alive without signs of oiling. 2 others were alive and oiled.

Magnificent Frigatebird: 7 were found one dead with no sign of oil, 2 dead with signs of oil, 2 alive with signs of oil, and 2 dead where the oiling status was not reported.

Laughing Gulls: 2654 - 1208 dead, no oil, 256 alive no oil; 704 dead, oiled, 201 alive and oiled; 285 dead, oiling status not reported)

Least Terns: 106 - 40 dead no oil, 5 alive no oil; 43 dead oiled, 6 alive oiled; 12 dead status not reported.

Royal Terns: 270 - 83 dead, no oil, 28 alive, no oil; 92 dead, oiled, 47 alive, oiled; 20 dead no report of oiling status

Sandwich Tern: 63-20, 6; 18, 10, 9

Roseate Tern - 0 (but there were 107 unidentified terns: 50, 1; 37, 1; 18

Sooty Tern - 0

Bridled Tern - 0

Brown Noddy - 0

Black Noddy - 0

Double - crested Cormorants - 18 - 10, 5; 0,1; 2