Conservation of marine birds of northern North America: / papers from the international symposium held at the Seattle Hyatt House

by Unknown

Results

The OVI for each of 176 bird species is listed in Table 1. The average OVI for 22 avian families comprising 128 species that are neither rare stragglers nor endangered ranged from 19 to 88, with a mean of 51 (Table 3).

Tables 4 and 5 show a possible use for the OVI by comparing impacts in two large, widely separated areas. A species list from Southeast Alaska (U.S. Forest Service and Alaska Department of Fish and Game 1970) is compared with a list from the Aleutian Islands (U.S. Fish and Wildlife Service 1974). Only commonly occurring species are included. These tables graphically display rather strong differences in the vulnerability of the avifauna of each area. A person explaining comparative impacts of projects might use the tables in the following way:

• Column 1, with scores from 1 to 20 points, indicates birds with a low level of project involvement, where damage or future costs would not be expected. As this will normally be the longest list, as in Tables 4 and 5, one would expect an immediate rise of interest on the part of the planning agency, which is probably eager to learn where problems will be fewest.

• Column 2 (21 to 40 points) indicates birds for which there is a low level of concern. Perhaps all that is needed is a review to determine if special characteristics of the project might be detrimental to these species.

• Column 3 (41 to 60 points) might be called "trial and error" species. If some birds are adversely affected, it will not be catastrophic. As the project develops it will be merely necessary to monitor these to make sure their status is not adversely affected. If it is, there will be time to develop conservation measures.

• Columns 4 and 5 (61 to 80 points and 81 to 100 points, respectively) include the species where concern is high. It is for these species that research money will be needed, where project modifications may be required, where a contingency plan in case of disaster is needed, where a conservation technology will be needed, and where periodic project shutdown could be called for.

Table 1. Oil Vulnerability Index (OVI) for waterbirds in the Northeast Pacific Region.

Family, common (AOU) name and scientific name	Range				Pop­u­la­tion		Hab­its						Mor­tal­i­ty				An­nu­al ex­po­sure				OVI
	B r e e d i n g r a n g e s i z e	M i g r a t i o n l e n g t h	W i n t e r r a n g e s i z e	M a r i n e o r i e n t a t i o n	P o p u l a t i o n s i z e	P r o d u c t i v i t y	R o o s t i n g	F o r a g i n g	E s c a p e	F l o c k i n g o n w a t e r	N e s t i n g d e n s i t y	S p e c i a l i z a t i o n	H u n t e d b y m a n	A n i m a l d e p r e d a t i o n s	N o n - o i l p o l l u t i o n	H i s t o r y o f o i l i n g	S p r i n g	S u m m e r	F a l l	W i n t e r	T o t a l P o i n t s
Gaviidae
Common loon (Gavia immer)	1	3	3	3	1	5	5	5	5	1	1	3	1	1	3	3	1	0	1	1	47
Yellow-billed loon (G. adamsii)	3	3	5	3	5	5	5	5	5	1	1	3	1	1	0	3	5	1	5	5	65
Arctic loon (G. arctica)	3	3	3	3	3	5	5	5	5	1	1	3	1	1	3	3	3	1	3	3	58
Red-throated loon (G. stellata)	1	3	3	5	1	5	5	5	5	1	1	3	1	1	3	3	1	0	1	1	49
Podicipedidae
Red-necked grebe (Podiceps grisegena)	1	3	3	3	1	3	5	5	5	1	1	3	0	1	3	3	1	0	1	1	44
Horned grebe (P. auritus)	1	3	3	3	1	3	5	5	5	3	1	3	0	3	3	3	1	0	1	1	48
Western grebe (Aechmophorus occidentalis)	3	3	3	5	1	3	5	5	5	5	1	3	0	1	3	5	1	0	1	3	56
Diomedeidae
Short-tailed albatross (Diomedea albatrus)					99															1	100
Black-footed albatross (D. nigripes)	5	1	1	5	3	5	5	3	3	1	5	5	0	0	1	3	1	1	1	1	50
Laysan albatross (D. immutabilis)	5	1	1	5	3	5	5	3	3	1	5	5	0	0	1	3	1	1	1	3	52
Procellaridae
Fulmar (Fulmarus glacialis)	3	3	1	5	1	5	5	3	3	3	5	3	0	1	1	3	3	3	3	3	57
Pink-footed shearwater (Puffinus creatopus)	3	1	1	5	1	5	5	3	3	3	5	3	0	1	1	3	1	1	1	1	47
Pale-footed shearwater (P. carneipes)																				1	1
New Zealand shearwater (P. bulleri)																				1	1
Sooty shearwater (P. griseus)	1	1	1	5	1	5	5	3	3	5	5	3	1	1	1	3	1	5	1	0	51
Slender-billed shearwater (P. tenuirostris)	1	1	3	5	1	5	5	3	3	5	5	3	1	1	1	3	1	5	1	0	53
Scaled petrel (Pterodroma inexpectata)																				1	1
Cooks petrel (P. cookii)																				1	1
Hydrobatidae
Fork-tailed storm-petrel (Oceanodroma furcata)	3	3	3	5	1	5	5	3	3	3	5	3	0	1	1	3	5	5	5	5	67
Leach's storm-petrel (O. leucorhoa)	1	3	1	5	1	5	5	3	3	3	5	3	0	1	1	3	5	5	5	5	63
Pelecanidae
Brown pelican (Pelecanus occidentalis)																				1	1
Phalacrocoracidae
Double-crested cormorant (Phalacrocorax auritus)	1	3	3	3	3	3	1	5	3	1	3	3	0	1	3	5	3		3	5	52
Brandt's cormorant (P. penicillatus)	3	3	3	5	3	3	1	5	3	1	3	3	0	1	3	5	3	3	3	3	57
Pelagic cormorant (P. pelagicus)	3	3	3	5	3	3	1	5	3	3	3	3	0	1	3	5	5	1	5	5	63
Red-faced cormorant (P. urile)	5	3	3	5	3	3	1	5	3	3	3	3	0	1	1	5	5	5	3	3	63
Ardeidae
Great blue heron (Ardea herodias)	1	3	1	1	3	3	1	1	1	1	3	3	0	1	1	1	1	1	1	1	29
Anatidae
Whooper swan (Olor cygnus)																				1	1
Whistling swan (O. columbianus)	3	3	3	3	3	3	5	3	1	5	1	3	3	1	3	1	3	0	3	0	50
Trumpeter swan (O. buccinator)	5	5	3	3	5	3	5	5	1	5	1	5	1	1	3	3	3	0	3	3	63
Canada goose (Branta canadensis)	1	3	1	1	5	3	1	1	1	3	1	1	5	1	1	1	1	1	1	1	34
Black Brant (B. nigricans)	3	3	3	5	3	3	5	5	3	5	3	3	5	1	3	5	3	1	5	3	70
Emperor goose (Philacte canagica)	3	5	5	5	3	3	3	3	3	3	3	3	3	1	1	5	5	3	5	5	70
White-fronted goose (Anser albifrons)	3	3	3	1	3	3	1	1	1	1	1	1	5	1	3	1	1	1	1	1	36
Snow goose (Chen hyperborea)	1	3	1	1	3	3	1	1	1	1	1	1	5	1	3	1	1	1	1	1	32
Mallard (Anas platyrhynchos)	1	3	1	1	1	1	1	3	3	3	1	1	5	3	3	1	1	1	1	1	36
Gadwall (A. strepera)	3	3	1	1	1	1	1	3	3	3	1	1	5	3	3	1	1	1	1	1	38
Pintail (A. acuta)	1	3	1	1	1	1	1	3	3	3	1	1	5	3	3	1	1	1	1	1	36
Common teal (A. crecca)																		1			1
Green-winged teal (A. carolinensis)	1	3	1	1	1	1	1	3	3	1	1	1	5	3	3	1	1	1	1	1	34
Blue-winged teal (A. discors)																		1			1
Cinnamon teal (A. cyanoptera)																		1			1
European wigeon (Mareca penelope)																		1			1
American wigeon (M. americana)	1	3	1	1	1	1	1	3	3	3	1	1	5	3	3	1	1	1	1	1	36
Shoveler (Spatula clypeata)	1	3	1	1	1	1	1	3	3	1	1	1	5	3	3	1	1	1	1	1	34
Redhead (Aythya americana)	1	3	1	1	5	3	5	5	5	3	1	3	5	1	3	3	1	1	1	1	52
Ring-necked duck (A. collaris)																	1				1
Canvasback (A. valisineria)	1	3	1	1	5	3	5	5	5	3	1	3	5	1	3	3	1	1	1	1	52
Greater scaup (A. marila)	1	3	1	5	1	3	5	5	5	3	1	3	5	1	3	3	1	1	1	1	52
Lesser scaup (A. affinis)	1	3	1	3	1	3	5	5	5	3	1	3	5	1	3	3	1	1	1	1	50
Common goldeneye (Bucephala clangula)	1	3	1	3	1	3	5	5	5	3	1	3	3	1	3	3	1	1	1	1	48
Barrow's goldeneye (B. islandica)	3	3	1	3	1	3	5	5	5	3	1	3	3	1	3	3	3	1	3	3	56
Bufflehead (B. albeola)	1	3	1	3	1	3	5	5	5	3	1	3	1	1	3	3	3	1	3	3	52
Oldsquaw (Clangula hyemalis)	1	3	1	5	1	3	5	5	5	5	1	3	3	1	1	5	5	3	5	5	66
Harlequin duck (Histrionicus histrionicus)	3	5	1	5	1	3	1	3	3	3	1	3	1	1	1	5	5	5	5	5	60
Steller's eider (Polysticta stelleri)	3	3	5	5	1	3	5	5	5	5	1	3	3	1	1	5	5	3	5	5	72
Common eider (Somateria mollissima)	3	5	3	5	1	3	5	5	5	3	1	3	1	1	1	5	5	3	5	5	68
King eider (S. spectabilis)	3	5	3	5	1	3	5	5	5	5	1	3	1	1	1	5	5	3	5	5	70
Spectacled eider (Lampronetta fisheri)	5	5	5	5	3	3	5	5	5	5	3	3	1	1	1	5	5	3	5	5	78
White-winged scoter (Melanitta deglandi)	3	3	3	3	1	3	5	5	5	5	1	3	3	1	3	5	5	5	5	5	72
Surf scoter (M. perspicillata)	3	3	3	3	1	3	5	5	5	5	1	3	3	1	3	5	5	5	5	5	72
Common scoter (Oidemia nigra)	3	3	3	3	1	3	5	5	5	5	1	3	3	1	3	5	5	5	5	5	72
Ruddy duck (Oxyura jamaicensis)	1	3	1	3	1	1	5	5	5	5	1	5	5	3	3	3	1	0	1	3	55
Hooded merganser (Laphodytes cucullatus)	1	3	1	1	3	3	3	5	3	1	1	3	1	1	3	1	1	0	1	1	37
Common merganser (Mergus merganser)	1	3	3	3	1	3	3	5	5	3	1	3	3	1	3	3	3	3	3	3	56
Red-breasted merganser (M. serrator)	1	3	3	3	1	3	3	5	5	3	1	3	3	1	3	3	3	3	3	3	56
Accipitridae
Bald eagle (Haliaeetus leucocephalus)	1	5	3	3	5	5	0	1	1	0	1	5	0	0	5	3	5	5	5	5	58
Steller's sea eagle (H. pelagicus)																		1			1
Marsh hawk (Circus cyaneus)	1	3	1	1	1	3	1	1	1	0	1	1	0	0	1	1	1	0	1	0	19
Pandionidae
Osprey (Pandion haliaetus)	1	3	1	1	5	5	0	1	1	0	1	5	3	1	5	1	1	1	1	0	37
Falconidae
Peregrine falcon (Falco peregrinus)	1	3	1	1	5	5	0	1	1	0	1	3	3	0	5	1	3	3	3	1	41
Gruidae
Sandhill crane (Grus canadensis)	1	3	1	1	1	3	1	1	1	0	1	1	3	1	1	1	1	1	1	0	24
Rallidae
American coot (Fulica americana)	1	3	1	1	1	1	3	3	1	3	1	1	3	3	3	1	1	0	1	1	33
Haematopodidae
Black oystercatcher (Haematopus bachmani)	5	5	5	5	3	5	1	1	1	1	1	5	0	1	3	3	5	5	5	5	65
Charadriidae
Ringed plover (Charadrius hiaticula)																		1			1
Semipalmated plover (C. semipalmatus)	1	1	1	1	1	3	1	1	1	1	1	1	0	5	1	1	3	1	3	0	28
Mongolian plover (C. mongolus)																				1	1
Killdeer (C. vociferus)	1	3	1	1	1	3	1	1	1	1	1	1	0	5	1	1	1	1	1	0	26
Dotterel (Eudromias morinellus)																		1			1
American golden plover (Pluvialis dominica)	1	1	1	3	3	3	3	1	1	3	1	3	3	5	0	1	1	0	1	0	35
Black-bellied plover (Squatarola squatarola)	1	1	1	5	3	3	1	1	1	3	1	3	3	5	1	3	3	1	3	0	43
Surfbird (Aphriza virgata)	5	1	5	5	3	3	1	1	1	3	1	3	0	5	1	3	5	0	5	3	54
Ruddy turnstone (Arenaria interpres)	1	1	3	5	3	3	1	1	1	3	1	3	0	5	1	3	3	3	3	0	44
Black turnstone (A. melanocephala)	5	3	3	5	3	3	1	1	1	3	1	3	0	5	1	3	5	3	5	3	57
Scolopacidae
Common snipe (Capella gallinago)	1	1	1	1	1	3	1	1	1	1	1	1	5	5	1	1	1	1	1	0	29
Eurasian curlew (Numenius arquata)																		1			1
Whimbrel (N. phaeopus)	1	1	1	3	3	3	1	1	1	3	1	3	1	3	1	3	3	1	3	0	37
Bristle-thighed curlew (N. tahitiensis)	5	1	1	5	5	3	3	1	1	3	1	1	1	3	1	3	3	1	3	0	45
Eskimo curlew (N. borealis)					99													1			100
Upland plover (Bartramia longicauda)	1	1	1	0	5	3	1	1	1	0	1	1	3	3	1	0	1	1	1	0	26
Spotted sandpiper (Actitis macularia)	1	3	1	1	1	3	1	1	1	1	1	1	0	3	1	1	1	1	1	0	24
Common sandpiper (Tringa hypoleucos)																		1			1
Solitary sandpiper (T. solitaria)																		1			1
Wood sandpiper (T. glareola)																		1			1
Wandering tattler (Heteroscelus incanum)	5	1	1	5	5	3	1	1	1	3	1	3	1	3	1	3	5	0	5	0	48
Polynesian tattler (H. brevipes)																			1		1
Willet (Catoptrophorus semipalmatus)																		1			1
Greater yellowlegs (Totanus melanoleucus)	1	5	1	1	3	3	1	1	1	1	1	1	3	3	1	1	1	0	1	0	30
Lesser yellowlegs (T. flavipes)	1	5	1	1	3	3	1	1	1	1	1	1	3	3	1	1	1	0	1	0	30
Spotted redshank (T. totanus)																		1			1
Greenshank (Tringa nebularia)																		1			1
Knot (Calidris canutus)	1	1	1	5	5	3	1	1	1	3	1	1	1	3	1	3	3	3	1	0	39
Great knot (C. tenuirostris)																		1			1
Rock sandpiper (Erolia ptilocnemis)	5	3	3	5	3	3	1	1	1	3	1	3	0	3	1	3	5	5	5	5	59
Sharp-tailed sandpiper (E. acuminata)	3	1	3	5	3	3	1	1	1	3	1	3	0	3	3	3	3	0	3	3	46
Pectoral sandpiper (E. melanotos)	1	1	3	1	3	3	1	1	1	1	1	1	0	3	1	1	3	3	3	0	32
White-rumped sandpiper (E. fuscicollis)																				1	1
Baird sandpiper (E. bairdii)	1	3	3	1	3	3	1	1	1	1	1	1	0	3	1	1	3	3	3	0	34
Least sandpiper (E. minutilla)	1	3	3	3	1	3	1	1	1	1	1	1	0	3	1	1	3	3	3	0	34
Long-toed stint (E. subminuta)																		1			1
Temminck's stint (Calidrus temminckii)																		1			1
Rufous-necked sandpiper (E. ruficollis)	3	1	3	5	3	3	1	1	1	3	1	1	0	3	1	3	1	1	1	0	36
Curlew sandpiper (E. ferruginea)																		1			1
Dunlin (E. alpina)	1	3	1	5	1	3	1	1	1	1	1	1	0	3	3	3	3	3	3	3	41
Short-billed dowitcher (Limnodromus griseus)	3	3	3	3	3	3	1	1	1	1	1	3	3	3	1	3	3	3	3	0	45
Long-billed dowitcher (L. scolopaceus)	5	3	3	3	3	3	1	1	1	1	1	3	3	3	1	3	3	3	3	0	47
Stilt sandpiper (Micropalama himantopus)																		1			1
Semipalmated sandpiper (Ereunetes pusillus)	1	3	1	3	1	3	1	1	1	1	1	1	0	3	1	1	3	5	3	0	34
Western sandpiper (E. mauri)	5	3	3	5	1	3	1	1	1	1	1	1	0	3	3	3	3	5	3	1	47
Buff-breasted sandpiper (Tryngites subruficollis)																		1			1
Marbled godwit (Limosa fedoa)																		1			1
Bar-tailed godwit (L. lapponica)	3	1	1	5	3	3	1	1	1	3	1	3	3	3	1	3	5	5	3	0	49
Hudsonian godwit (L. haemastica)																		1			1
Black-tailed godwit (L. limosa)																		1			1
Ruff (Philomachus pugnax)																		1			1
Sanderling (Crocethia alba)	3	1	1	5	3	3	1	1	1	3	1	3	0	3	1	3	3	3	3	3	45
Spoon-billed sandpiper (Eurynorhynchus pygmeum)																		1			1
Phalaropodidae
Red phalarope (Phalaropus fulicarius)	3	1	1	5	1	3	5	5	1	5	1	5	0	3	1	5	5	3	5	0	58
Wilson's phalarope (Steganopus tricolor)																			1		1
Northern phalarope (Lobipes lobatus)	3	1	3	5	1	3	5	5	1	5	1	5	0	3	3	5	5	3	5	0	62
Stercorariidae
Pomarine jaeger (Stercorarius pomarinus)	1	1	1	5	1	3	3	3	1	3	1	3	1	1	1	3	3	3	3	0	41
Parasitic jaeger (S. parasiticus)	1	1	1	5	1	3	3	3	1	3	1	3	1	1	3	3	3	3	3	0	43
Long-tailed jaeger (S. longicaudus)	1	1	1	3	1	3	3	3	1	3	1	3	1	1	1	3	3	3	3	0	39
Skua (Catharacta skua)																				1	1
Laridae
Glaucous gull (Larus hyperboreus)	1	5	3	3	1	3	3	3	1	3	3	1	0	1	1	1	3	3	3	3	45
Glaucous-winged gull (L. glaucescens)	5	1	3	5	1	3	3	3	1	3	5	1	1	1	1	1	5	5	5	3	56
Slaty-backed gull (L. schistisagus)																				1	1
Western gull (L. occidentalis)	3	1	3	5	1	3	3	3	1	3	5	1	1	1	1	1	3	3	3	3	48
Herring gull (L. argentatus)	1	3	1	3	1	3	1	3	1	3	1	1	1	1	1	1	3	3	3	3	38
Thayer's gull (L. thayeri)	3	3	5	3	1	3	1	3	1	3	1	1	1	1	1	1	3	1	3	3	42
California gull (L. californicus)	3	5	3	3	1	3	3	3	1	3	1	1	1	1	1	1	1	1	1	1	38
Ring-billed gull (L. delawarensis)	1	5	3	3	1	3	3	3	1	3	1	1	1	1	1	1	1	1	1	1	36
Mew gull (L. canus)	1	5	3	3	1	3	3	3	1	3	1	1	1	1	1	1	3	3	3	3	44
Black-headed gull (L. ridibundus)																		1			1
Franklin's gull (L. pipixcan)																		1			1
Bonaparte's gull (L. philadelphia)	1	5	3	3	1	3	3	3	1	3	1	1	1	1	1	1	3	1	3	1	40
Heerman's gull (L. heermanni)																				1	1
Ivory gull (Pagophila eburnea)	1	5	3	5	3	3	3	3	1	3	1	3	0	1	1	1	1	1	1	3	43
Black-legged kittiwake (Rissa tridactyla)	1	3	3	5	1	3	3	3	1	3	5	3	0	1	1	1	3	3	3	3	49
Red-legged kittiwake (R. brevirostris)	5	5	5	5	3	3	3	3	1	3	5	3	0	1	0	1	5	5	5	5	66
Ross' gull (Rhodostethia rosea)	5	5	3	5	3	3	3	3	1	3	5	5	0	1	0	1	3	1	3	3	56
Sabine's gull (Xema sabini)	3	3	3	5	1	3	3	3	1	3	1	3	0	1	1	1	3	3	3	0	44
Common tern (Sterna hirundo)																			1		1
Arctic tern (S. paradisaea)	1	1	1	3	1	3	3	3	1	3	1	1	0	1	1	1	3	1	3	0	32
Aleutian tern (S. aleutica)	5	3	3	5	3	3	3	3	1	3	1	1	0	1	1	1	5	5	5	1	53
Caspian tern (Hydroprogne caspia)																			1		1
Black tern (Chlidonias niger)																			1		1
Alcidae
Common murre (Uria aalge)	1	5	3	5	1	5	5	5	5	5	5	3	1	1	3	5	3	3	3	3	70
Thick-billed murre (U. lomvia)	1	5	3	5	1	5	5	5	5	5	5	3	1	1	3	5	3	3	3	3	70
Dovekie (Plautus alle)																		1			1
Black guillemot (Cepphus grylle)	1	5	3	5	3	5	5	5	5	3	5	5	1	1	1	5	3	3	3	3	70
Pigeon guillemot (C. columba)	5	5	3	5	3	5	5	5	5	3	5	5	1	1	3	5	5	5	5	3	82
Marbled murrelet (Brachyramphus marmoratus)	5	5	3	5	1	5	5	5	5	3	5	5	1	3	3	5	5	5	5	5	84
Kittlitz's murrelet (B. brevirostris)	5	5	5	5	1	5	5	5	5	5	5	5	1	3	3	5	5	5	5	5	88
Xantus' murrelet (Endomychura hypoleuca)																				1	1
Ancient murrelet (Synthliboramphus antiquus)	3	3	3	5	1	5	5	5	5	5	5	5	1	3	3	5	3	3	3	3	74
Cassin's auklet (Ptychoramphus aleutica)	5	3	5	5	1	5	5	5	5	5	5	5	1	3	3	5	5	5	5	3	84
Parakeet auklet (Cyclorrhynchus psittacula)	3	3	3	5	1	5	5	5	5	5	5	5	1	3	3	5	5	5	5	3	80
Crested auklet (Aethia cristatella)	3	3	3	5	1	5	5	5	5	5	5	5	1	3	1	5	5	3	5	3	76
Least auklet (A. pusilla)	3	3	3	5	1	5	5	5	5	5	5	5	1	3	3	5	5	5	5	3	80
Whiskered auklet (A. pygmaea)	5	5	5	5	1	5	5	5	5	5	5	5	1	3	3	5	5	5	5	5	88
Rhinoceros auklet (Cerorhinca monocerata)	3	3	3	5	1	5	5	5	5	5	5	5	1	3	3	5	3	3	3	3	74
Horned puffin (Fratercula corniculata)	3	5	3	5	1	5	5	5	5	3	5	5	1	3	1	5	3	3	3	3	72
Tufted puffin (Lunda cirrhata)	3	5	3	5	1	5	5	5	5	3	5	5	1	3	1	5	3	3	3	3	72
Alcedinidae
Belted kingfisher (Megaceryle alcyon)	1	1	3	1	1	1	1	5	1	0	1	3	0	3	1	1	1	1	1	1	28
Corvidae
Common raven (Corvus corax)	1	1	1	1	1	1	1	1	1	0	1	1	3	1	1	1	1	1	1	1	21
Northwestern crow (C. caurinus)	3	5	3	3	1	1	1	1	1	0	1	3	1	1	1	1	5	5	5	5	47

Table 2. Criteria and points used in calculating Oil Vulnerability Index.

	Point assignment
	1	3	5
Range
Breeding	Large	Medium	Small
Migration	Long	Medium	Short
Winter	Large	Medium	Small
Marine orientation	Coastal zone	Intertidal	Open water
Population
Size	Large	Medium	Small
Productivity	Large	Medium	Small
Habits
Roosting	Shore	Drift	Water
Foraging	Walking	Flying	Swimming
Escape	Leave area	Fly	Dive
Flocking	Small	Medium	Large
Nesting density	Low	Medium	High
Specialization	Low	Medium	High
Mortality
Hunted by man	Low	Medium	High
Animal depredations	Low	Medium	High
Non-oil pollution	Low	Medium	High
History of oiling	Low	Medium	High
Exposure
Spring	Low	Medium	High
Summer	Low	Medium	High
Fall	Low	Medium	High
Winter	Low	Medium	High