Pomarine Jaeger 

Order: Charadriiformes

Family: Stercorariidae

Field Marks:

Light morphs: dark brown upperparts, black cap, white underparts and collar with yellow tint on sides of neck, broad brown breast band

Dark morph: uncommon, but dark brown overall

All morphs have white shafts on outermost primaries, and white patch on underside of primaries

In alternate plumage, central rectrices are long, broad, with a half-twist, making them conspicuous in side-view

Pale bill with dark tip

Sex:Monomorphic

Habitat: Pelagic ocean waters.

Life History:

Occurs offshore of CA in winter

Breeding success depends entirely on Arctic lemming population sizes

Black Tern Basic Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Dark gray upperparts, white head and underparts, and black crown

In alternate plumage, head, breast, and belly black; white vent

Bill and legs dark

Sex:Monomorphic

Habitat:Freshwater marshes and agricultural fields

Life History:

Neotropical migrant, nesting in CA in summer

Unique in that it eats insects as well as fish, and nests in fresh water

Conservation:

CA Species of Special Concern

Likely causes include loss of wetland habitat and pesticide pollution

Black Tern Alternate Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Dark gray upperparts, white head and underparts, and black crown

In alternate plumage, head, breast, and belly black; white vent

Bill and legs dark

Sex:Monomorphic

Habitat:Freshwater marshes and agricultural fields

Life History:

Neotropical migrant, nesting in CA in summer

Unique in that it eats insects as well as fish, and nests in fresh water

Conservation:

CA Species of Special Concern

Likely causes include loss of wetland habitat and pesticide pollution

Least Tern

Order:Charadriiformes

Family:Laridae

Field Marks:

Upperparts gray with white underparts and two black outer primaries

In basic plumage: dark nape, crown, and eyestripe, with white flecking; bill black

In alternate plumage: black cap and loral stripe, with white forehead; bill yellow or orange with a dark tip

Sex:Monomorphic

Habitat:

Sandy beaches, mudflats, estuaries, bays, and rivers

Life History:

Neotropical migrant, nesting in CA in summer

Smallest North American tern

Eats mostly small fish, but also crustaceans and insects

Conservation:

Federal and CA Endangered Species (California subspecies S.a. browni only)

Causes include loss and fragmentation of nesting habitat due to residential development; and enhanced populations of nest predators (Ravens, feral cats, foxes)

Caspian Tern 

Order:Charadriiformes

Family:Laridae

Field Marks:

Upperparts pale gray, with white underparts, rump, and tail

Black cap extends below eye and ends in slight crest

Underside of primaries dark gray or blackish, forming a patch

Dark red bill with dusky tip

In basic plumage: cap mottled with brown and white

In alternate plumage: cap all black

Sex:Monomorphic

Habitat:Estuaries, salt marshes, rivers, lakes

Life History:

Occurs year-round in parts of CA

Largest tern in the world

Elegant Tern Alternate Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Bluish-gray upperparts with darker gray primaries

Underparts white, and often tinged pink

Black cap with long, shaggy crest

Long, slender bill, light yellow to reddish-orange; appears decurved

In basic plumage: forehead and lores white

In alternate plumage: black cap extends through forehead and lores

Sex:Monomorphic

Habitat:Coastal ocean waters, bays, and estuaries

Life History:

Breeding success appears related to El Nino, which affects its key prey: the northern anchovy

Conservation:

CA Species of Special Concern

Only a few breeding colonies in the United States, in southern CA, and only 5 total; extremely vulnerable to disturbance

Elegant Tern Basic Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Bluish-gray upperparts with darker gray primaries

Underparts white, and often tinged pink

Black cap with long, shaggy crest

Long, slender bill, light yellow to reddish-orange; appears decurved

In basic plumage: forehead and lores white

In alternate plumage: black cap extends through forehead and lores

Sex:Monomorphic

Habitat:Coastal ocean waters, bays, and estuaries

Life History:

Breeding success appears related to El Nino, which affects its key prey: the northern anchovy

Conservation:

CA Species of Special Concern

Only a few breeding colonies in the United States, in southern CA, and only 5 total; extremely vulnerable to disturbance

Forster's Tern Alternate Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray upperparts and silvery primaries; underparts white

In basic plumage: black eyepatches, white forehead, black bill

In alternate plumage: black cap extends just to eye and over forehead, bill orange with black tip

Sex:Monomorphic

Habitat:Fresh, brackish, and saltwater marshes

Life History:

Occurs year-round in parts of CA

Only tern almost entirely restricted to North America all year

Forster's Tern Juvenile

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray upperparts and silvery primaries; underparts white

In basic plumage: black eyepatches, white forehead, black bill

In alternate plumage: black cap extends just to eye and over forehead, bill orange with black tip

Sex:Monomorphic

Habitat:Fresh, brackish, and saltwater marshes

Life History:

Occurs year-round in parts of CA

Only tern almost entirely restricted to North America all year

Black Skimmer Alternate Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Blackish upperparts with white underparts and tail

Two-toned bill black and tip, red at base

Bright red-orange feet

In basic plumage: nape is white

In alternate plumage: nape is black

Sex:Monomorphic

Habitat:Sandy beaches, estuaries, and salt marshes

Life History:

Occurs year-round in parts of CA

Recent invader of CA, first recorded at Salton Sea in 1968

Conservation:

CA Species of Special Concern due to small numbers of nesting colonies, vulnerable to disturbance

Black Skimmer Basic

Order:Charadriiformes

Family:Laridae

Field Marks:

Blackish upperparts with white underparts and tail

Two-toned bill black and tip, red at base

Bright red-orange feet

In basic plumage: nape is white

In alternate plumage: nape is black

Sex:Monomorphic

Habitat:Sandy beaches, estuaries, and salt marshes

Life History:

Occurs year-round in parts of CA

Recent invader of CA, first recorded at Salton Sea in 1968

Conservation:

CA Species of Special Concern due to small numbers of nesting colonies, vulnerable to disturbance

Yellow-footed Gull   

Order:Charadriiformes

Family:Laridae

Field Marks:

Dark gray mantle and upperwing

Extensively black wing tips with small white spots

Yellow iris with bright yellow orbital ring

Yellow bill with red spot

Yellow legs

Unstreaked white head year-round

Sex:Monomorphic

Habitat:Beaches, mudflats, hypersaline lakes

Life History:

Regularly occurs at Salton Sea during postbreeding dispersal

Entire breeding range is in the Gulf of California

Glaucous Gull  

Order:Charadriiformes

Family:Laridae

Field Marks:

Very pale gray mantle and upperwing

Wingtips unmarked and white

Yellow iris with yellow to orange orbital ring

Yellow bill with red spot

Pink legs

Slightly streaked head (clean white in alternate plumage)

Sex:Monomorphic

Habitat:

Coasts, lakes, agricultural fields, and garbage dumps

Life History:

Occurs in CA in winter

Western Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Dark gray mantle and upperwing

Extensive, but not clearly defined black wing tips with white spots

Yellow iris with yellow-orange orbital ring

Yellow bill with red spot

Pink legs

Head virtually unstreaked (and clean white in alt)

Sex:Monomorphic

Habitat:

Offshore islands, beaches, bays, estuaries, garbage dumps

Life History:

Occurs year-round in CA

Nearly 85% of the CA population breeds on the Farallon or Channel Islands

Glaucous-winged Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Medium gray mantle and upper wing

Gray wingtips with white subterminal spots

Dark iris with pink to purple orbital ring

Yellow bill with red spot

Pink legs

Neck faintly barred brown (clean white in alternate plumage)

Sex:Monomorphic

Habitat:

Bays, estuaries, beaches, mudflats, and garbage dumps

Life History:

Occurs in CA in winter

Thayer's Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray mantle and upperwing

Black wingtips restricted to outer webs of primaries; mostly white underwing

Usually dark iris with reddish-purple orbital ring

Yellow bill with red spot

Pink legs

Smudgy streaking on nape, extending toward breast (clean white in alternate plumage)

Sex:Monomorphic

Habitat:Beaches, estuaries, bays, and garbage dumps

Life History:

Occurs in CA in winter

Herring Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray mantle and upperwing

Limited black wing tips, not sharply contrasting, with small white spots

Yellow iris with yellow-orange orbital ring

Yellow bill with red spot

Pink legs

Extensive brownish-gray streaking on nape (clean white in alt plumage)

Sex:Monomorphic

Habitat:

Lakes, coastal bays, estuaries, and garbage dumps

Life History:

Occurs in CA in winter

California Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Medium gray mantle and upperwing

Extensive, clearly-defined black wing tips with small white spots

Dark iris with red orbital ring

Yellow bill with red and black marks

Yellow legs

Brownish streaks on nape (clean white in alternate plumage)

Sex:Monomorphic

Habitat:

Lakes, rivers, estuaries, mudflats, and inshore ocean waters

Life History:Occurs year-round in CA

Conservation:

CA Species of Special Concern

Threats include mainland predators reaching nesting islands in Mono Lake (at least world’s 2nd largest colony) when lake levels fall

Ring-billed Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray mantle, with paler primaries

Sharply contrasting black wing tips, with small white spot

Light iris with orange-red orbital ring

Broad black ring on yellow bill

Yellow legs

Pale gray mottling on head and nape (clean white in alternate plumage)

Sex:Monomorphic

Habitat:

Beaches, parking lots, and garbage dumps

Life History:

Primarily occurs in CA in winter, with some nesting in northeastern CA

Mew Gull

Order:Charadriiformes

Family:Laridae

Field Marks:

Medium gray mantle and upperwing

Primaries tipped black, with large white spots

Dark iris with red orbital ring 

Short, thin yellow to greenish-yellow bill 

Yellow legs

Heavy grayish-brown mottling on head and neck (entirely white in alt) 

Sex:Monomorphic

Habitat:

Estuaries, beaches, mudflats, rivers, lakes, garbage dumps

Life History:

Occurs in CA in winter

Very adaptable in its habitat selection, foraging and reproductive behaviors

Bonaparte’s Gull  Alternate Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Pale gray mantle and upperwing

Outer primaries mostly white with black tips

Dark iris with dark orbital ring

Thin black bill

Orange-red legs

Head entirely white with dark ear-spot behind eye and gray hindneck

In alternate plumage, head entirely black with white eye-crescents

Sex:Monomorphic

Habitat:Bays, estuaries, lakes, and rivers

Life History:

Occurs in CA in winter

One of the smallest gulls of North America

Heermann’s Gull Basic Plumage

Order:Charadriiformes

Family:Laridae

Field Marks:

Dark brownish-gray mantle and upperwing

Wingtips black, blending into dark mantle

Dark iris with red orbital ring

Red bill with black tip

Black legs

Dark gray head (white in alternate plumage)

Black tail with white tips

Sex:Monomorphic

Habitat:

Offshore ocean waters, rocky shorelines, bays, and estuaries

Life History:

Occurs in CA in winter

Common Murre Basic Plumage

Order:Charadriiformes

Family:Alcidae

Field Marks:

Large, with blackish brown upperparts and white underparts

Flanks and thighs striated brown and white

Secondaries tipped white, creating a white edge to folded wing

Long, straight, pointed, black bill

In basic plumage: chin, throat, and cheeks white

In alternate plumage: head and neck entirely dark

Sex:Monomorphic

Habitat:Pelagic ocean waters and offshore islands

Life History:

Occurs along CA coast in winter

Among the largest of the living Alcidae

Can dive up to 100 m deep

Common Murre Alternate Plumage

Order:Charadriiformes

Family:Alcidae

Field Marks:

Large, with blackish brown upperparts and white underparts

Flanks and thighs striated brown and white

Secondaries tipped white, creating a white edge to folded wing

Long, straight, pointed, black bill

In basic plumage: chin, throat, and cheeks white

In alternate plumage: head and neck entirely dark

Sex:Monomorphic

Habitat:Pelagic ocean waters and offshore islands

Life History:

Occurs along CA coast in winter

Among the largest of the living Alcidae

Can dive up to 100 m deep

Pigeon Guillemot

Order:Charadriiformes

Family:Alcidae

Field Marks:

In basic plumage: grayish upperparts with white underparts

In alternate plumage: blackish-brown overall

All plumages: white upper wing patch with dusky gray underwing

Long, pointed black bill; inside of mouth bright red

Bright red, relatively long legs

Sex:Monomorphic

Habitat: 

Rocky coastlines and coastal cliffs, mainland and offshore islands

Life History:

Occurs year-round off the coast of CA

Endemic to the North Pacific

Tend to dive directly to sea bed in inshore waters, 10-30 m deep

Tufted Puffin Basic Plumage

Order:Charadriiformes

Family:Alcidae

Field Marks:

Brownish-black overall, with large orange bill and orange feet

In alternate plumage: white face mask with long golden plumes

Sex:Monomorphic

Habitat:Pelagic ocean waters

Life History:

Occurs year-round off the coast of CA

Known for bringing bill-fulls of small fish to juveniles, while eating mainly invertebrates themselves (squid and krill)

Conservation:

CA Species of Special Concern

Threats include declining sardine population, oil spills, introduced mammals, and human disturbance at nests

Xantus’s Murrelet

Order:Charadriiformes

Family:Alcidae

Field Marks:

Black to bluish-gray upperparts, with white underparts

Small wedge of white in front of eye, and all white below gape

Flanks mottled gray and white

Underwing usually pure white

Sex:Monomorphic

Habitat:

Nests on cliffs of offshore islands and forages in pelagic ocean waters

Life History:

Nests on offshore CA islands and winters along CA coast

Conservation:

CA Threatened due to small and declining breeding population

Craveri’s Murrelet 

Order:Charadriiformes

Family:Alcidae

Field Marks:

Brownish-black upperparts with white underparts

No wedge of white in front of eye, and some black on chin

Underwing grayish

Sex:Monomorphic

Habitat:Pelagic ocean waters

Life History:

Occurs off the CA coast during post-breeding dispersal from Mexico

Cassin’s Auklet   

Order:Charadriiformes

Family:Alcidae

Field Marks:

Dark gray upperparts fading to paler gray underparts and whitish belly

Whitish iris with small white crescents above and below eye

Pale base of lower mandible

Sex:Monomorphic

Habitat:

Nests on offshore islands and forages in pelagic ocean waters

Life History:

Occurs year-round off the coast of CA

80% of California’s population breeds on the Farallon Islands

Marbled Murrelet Alternate Plumage

Order:Charadriiformes

Family:Alcidae

Field Marks:

In basic plumage, bluish-black upperparts with white scapulars; mostly white underparts, sides of head, and partial collar

In alternate plumage: brownish-black upperparts with rusty scapulars; underparts light mottled brown

Sex:Monomorphic

Habitat:

Nests in coastal coniferous forests, and forages in bays and inshore ocean waters

Life History:

Occurs year-round along the CA coast

Conservation:

Federal Threatened and CA Endangered Species

Causes include loss of old growth forest for nesting and increases in avian predators in remaining habitat (Steller’s Jay and Common Raven)

Marbled Murrelet Basic Plumage

Order:Charadriiformes

Family:Alcidae

Field Marks:

In basic plumage, bluish-black upperparts with white scapulars; mostly white underparts, sides of head, and partial collar

In alternate plumage: brownish-black upperparts with rusty scapulars; underparts light mottled brown

Sex:Monomorphic

Habitat:

Nests in coastal coniferous forests, and forages in bays and inshore ocean waters

Life History:

Occurs year-round along the CA coast

Conservation:

Federal Threatened and CA Endangered Species

Causes include loss of old growth forest for nesting and increases in avian predators in remaining habitat (Steller’s Jay and Common Raven)