What do these ranks mean? ORBIC's ranking definitions

Horned Grebe

Podiceps auritus

List 2S2B,S5N

Red-Necked Grebe

Podiceps grisegena

List 2S1B,S4N
Clark's Grebe

Clark's Grebe

Aechmophorus clarkii

List 4S3B,S2N
Fork-Tailed Storm-Petrel

Fork-Tailed Storm-Petrel

Hydrobates furcatus

List 2S2B
California Brown Pelican

California Brown Pelican

Pelecanus occidentalis californicus

List 2S2N
Pelagic Cormorant

Pelagic Cormorant

Urile pelagicus

List 4S3
Brant

Brant

Branta bernicla

List 4S2N
Bufflehead

Bufflehead

Bucephala albeola

List 2S2B,S5N
Western Snowy Plover

Western Snowy Plover

Anarhynchus nivosus nivosus

List 2S2
Black Oystercatcher

Black Oystercatcher

Haematopus bachmani

List 4S3
Black-Necked Stilt

Black-Necked Stilt

Himantopus mexicanus

List 4S3?
Rock Sandpiper

Rock Sandpiper

Calidris ptilocnemis

List 4S3N
Marbled Murrelet

Marbled Murrelet

Brachyramphus marmoratus

List 2S2B
Cassin's Auklet

Cassin's Auklet

Ptychoramphus aleuticus

List 2S2B
Rhinoceros Auklet

Rhinoceros Auklet

Cerorhinca monocerata

List 2S2B
Tufted Puffin

Tufted Puffin

Fratercula cirrhata

List 2S1B
Western Grebe

Western Grebe

Aechmophorus occidentalis

List 4S4B,S2S3N
Trumpeter Swan

Trumpeter Swan

Cygnus buccinator

List 2S1?B,S3N
Harlequin Duck

Harlequin Duck

Histrionicus histrionicus

List 2S2B,S3N

Western River Lamprey

Lampetra ayresii

List 3S3?

Chum Salmon (Columbia River ESU)

Oncorhynchus keta pop. 3

List 1S2

Chum Salmon (Pacific Coast ESU)

Oncorhynchus keta pop. 4

List 2S2

Coho Salmon (Lower Columbia River ESU)

Oncorhynchus kisutch pop. 1

List 1S2

Coho Salmon (Southern Oregon/Northern California Coasts ESU)

Oncorhynchus kisutch pop. 2

List 1S2
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