-
COOP (Mar-Sep, warm water yrs)
- Pterodroma cookii
- Long wings, medium tail
- Cap same gray as back
- Can have white eyebrow
- M weaker w/ wear
- Mostly white underwing
- Small carpal bar
- Dark tips UnW
- Small and snappy
- Flight can be erratic
- Breeding:
- NZ
-
PYPE
- Pterodroma pycrofti
- Like COOP but:
- Slightly smaller
- Shorter thicker neck
- More gray on sides of head, neck
- Breeding:
- E Tropical Pacific to 110o west
-
STPE vs COOP
- Like COOP but:
- Darker cap
- More contrasting above
- Brighter blue-gray back
- Slightly shorter, broader wings
- Breeding:
- Juan Fernandez Islands, Chile
-
MOPE (Nov-Dec peak)
- Pterodroma inexpectata
- Like COOP above but stockier
- Dark gray belly
- Short tail
- Bold ulnar bar on underwing
- Fast direct flight
- Less acrobatic than others
- Cooler waters
- Breeding:
- NZ
-
STPE
- Pterodroma longirostris
- Cookilaria with dark hood
- Narrow wings, long tail
- White forehead
- White notch behind eye
- Mostly white underwing
- Short carpal bar
- Breeding:
- Juan Fernandez Islands, Chile
-
MUPE (Feb-Jun)
- Pterodroma ultima
- Like SOSH but smaller
- Buoyant bounding flight
- Wings bent at carpi
- Stocky body
- Thick neck, small stubby bill
- Inconspicuous M
- Pale chin
- Pale flash on pp below
- Breeding:
- South-Central Pacific
-
HAPE (Jul-Aug)
- Pterodroma sandwichensis
- Dark above w/ dark hood
- Small head
- White forehead
- Long narrow wings
- Long tapered tail
- Mostly white below
- Long thick black carpal bars
- Less shawl than GAPE
- White notch in shawl behind ear
- Whiter below
- Breeding:
- Maui
-
GAPE (Year-round)
- Pterodroma phaeopygia
- Dark above w/ dark hood
- Small head
- Speckled forehead not unique
- Long narrow wings
- Long tapered tail
- Mostly white below
- Long thick black carpal bars
- Axillary smudge (not diagnostic)
- Thick trailing UnW edge
- Deeper cap/shawl
- Thicker bill than HAPE
- Larger than COOP
- Vulnerable/Critical
- Breeding:
- Galapagos
-
GWPE (Year-round?)
- Pterodroma macroptera
- Large, all dark
- Dark underwing
- Big head like a fulmar
- Heavy black bill
- Powerful flight
- Gray face in Pacific
- Breeding:
- NZ
-
JFPE (May-Aug to 200 N)
- Pterodroma externa
- Large, Cookilaria-type
- Darker cap/eyepatch
- +/- White hind neck
- Long pointed wings
- Long tapered tail
- Thick bill
- Small underwing bar
- White mottled tail base
- Buoyant wheeling flight
- Sub/Tropical waters
- Breeding:
- Juan Fernandez Is, Chile
-
SOPE/PRPE (No records)
- Pterodroma solandri
- Like MUPE but:
- Longer broader wings
- Long wedge-shaped tail
- Thicker neck
- Very short thick bill
- Double wing flash below
- +/- Silvery sheen above
- Steadier flight than MUPE
- Breeding:
- Southwest Pacific
-
PAPE (1 Oct 2005)
- Procellaria parkinsoni
- Large and dark
- Long-winged
- Yellow bill plates rimmed black
- Med wedge-shaped tail
- Silvery pp and coverts UnW
- Like FFSH but:
- Toes often project
- Black feet
- Long pp projection on water
- E Tropical Pacific Mar-Nov
-
BUPE (Jul-Sep)
- Bulweria bulwerii
- Dark, slim, long-tailed
- Pale crescent on upperwing
- Bat-like flight
- Confused with storm-petrels
- Like SRTS w/ pale upper wing
- Breeding:
- West and Central Pacific
-
KEPE (Feb-Oct to 200 N)
- Pterodroma neglecta
- Thickset & polymorphic
- Long broad wings
- Short square tail
- Jaeger/Skua plumage
- White pp shafts
- Sharp wing flash
- White or dark belly
- Breeding:
- Subtropical South Pacific
-
HEPE (Year-round to 150 N)
- Pterodroma heraldica
- Medium sized, dimorphic
- Lightly built
- Narrow wings
- Pale pp bases
- Medium-long tail
- Buoyant flight
- Light and Dark morphs
- White or dark belly
- Breeding:
- Tropical South Pacific
-
TAPE (May-Nov to 200 N)
- Pseudobulweria rostrata
- Med large, chocolate brown
- Dark hood, white belly & vent
- Pale pp ss bases
- Long narrow wings
- Long tapered tail
- Very thick black bill
- Languid wheeling flight
- Wings straight and stiff
- Albatross-like
- Tropical waters
- Breeding:
- Tropical South Pacific
-
-
Difficult Pairs
- SOPE GWPE MUPE KEPE HEPE
- COOP STPE PYPE JFPE (BULS)
- HAPE GAPE JFPE
- MUPE SOPE SOSH/SRTS CHSH
- HEPE KEPE
-
Dark Petrels
- MUPE
- SOPE
- HEPE
- KEPE dark morph
- GWPE
- PAPE
- BUPE
-
-
Hooded Petrels
- TAPE
- TRPE (Trindade)
- KEPE light morph
- HEPE light morph
-
-
BLSP (Apr-Oct)
- Oceanodroma melania
- Large, all black
- Forked tail
- Deep wingbeats
- Larger & browner than ASSP
- Fairly direct flight
- Warmer waters, nearshore
- Breeding:
- Channel Is, San Benito, Gulf CA
-
LSTP (Jul-Oct)
- Oceanodroma microsoma
- Tiny, all dark
- Small wedge-shaped tail
- Looks like all wings, no tail
- Narrow pointed wings
- Deep jerky wingbeats
- Somewhat erratic flight
- Little or no gliding
- Warm water years especially
- Breeding:
- San Benito & N Gulf of Calif
- Rare N of LA waters
-
LESP Nominate (Oct-Apr)
- Oceanodroma l. leucorhoa
- White rump longer than wide
- Dusky median tail stripe often
- Erratic hanging flight, like CONI
- Deep wingbeats
- Forked tail hard to see
- Usually well offshore
- Warmer waters
- Breeding:
- Aleutians to Channel Is
- Ainley's stays S of Guadalupe Is
- ssp. cheimomnestes
-
LESP Townsend's (Jul-Sep)
- O. leucorhoa soccoroensis
- ssp. soccoroensis
- Variable rump, us. intermediate
- White rump often wraps below
- Less median tail stripe
- Steadier flight than nominate
- Deep wingbeats
- Forked tail hard to see
- Usually well offshore
- Warmer waters
- Late breeder (Jun-Nov):
- Guadalupe Is.
-
LESP Chapman's (Jul-Sep/Yr round)
- Oceanodroma leucorhoa chapmani
- ssp. chapmani
- Dark rump
- Erratic hanging flight, like CONI
- Deep wingbeats
- Forked tail hard to see
- Usually far offshore
- Warmer waters
- Breeding:
- Coronado & San Benito Is.
-
WISP (Sep-Oct)
- Oceanites oceanicus
- Flight fast & swallow-like
- Feet project past tail
- Square or notched tail
- White rump wraps to vent
- Broad wings, short arms
- Smaller than LESP
- Wing molt Apr-Aug in Calif
- Breeding:
- Antarctica & South America
-
ASSP (Mar-Oct)
- Oceanodroma homochroa
- Med size, dark gray
- Long forked tail
- Pale rump
- Pale UnW and UpW bars
- Large square head
- Direct but fluttery flight
- Deep wingbeats
- Short glides in light winds
- Paler back & arms
- Here during breeding season
- Cooler waters
- Breeding:
- Farallons and Channel Islands
- Coronados and Todos Santos
- ENDANGERED
-
FTSP (Year round)
- Oceanodroma furcata
- Med sized, gray
- Flight low and direct
- Less erratic than LESP
- Weaving flight
- Stiff, fluttery, shallow wingbeats
- Short glides on arched wings
- Pale upperwing crescents
- Dark underwing coverts
- Like REPH/RNPH in basic
- Usually far offshore
- Cooler waters
- Mostly non-breeders here
- Breeding:
- Japan, Aleutians, N Calif
-
WRSP (Jul-Oct/Yr round)
- Oceanodroma tethys
- Small, black, broad white rump
- Flight erratic, bat-like
- Quick deep wingbeats
- Heavy black bill
- Wings angle back at carpi
- Pale upperwing crescents
- White rump largest of all
- Near and offshore
- Follows ships
- Breeding:
- Galapagos & Peru
-
TRSP (Jul 2007)
- Oceanodroma tristrami
- Very large all dark
- Deeply forked tail
- Bold upperwing bands
- Variably paler gray rump patch
- Fairly direct flight
- Shallow wingbeats
- Bounding in windy conditions
- One record
- Breeding:
- Western subtropical Pacific
- Matsudaira's has white pp bases
-
RISP (Hornby's; Aug 2005)
- Oceanodroma hornbyi
- Fairly large with forked tail
- Black cap and chest band
- White lores and forehead
- Black outer wing & trailing edge
- Gray-brown body & inner wing
- Bold pale wing bars
- Dark underwing, white belly
- Unmistakable
- Breeding:
- Presumed Peru & Chile
-
MASP (Apr-Oct to 17o N)
- Oceanodroma markhami
- Large all dark
- Paler than BLSP
- Long pointed wings
- Wings slightly bent at wrist
- Long deeply forked tail
- Buoyant flight +/- like LESP
- Easy wingbeats
- Long glides
- Breeding:
- Deserts of Peru, N. Chile
- Humboldt Current endemic
-
SWSP (no records)
- Oceanodroma monorhis
- Swinhoe's
- Medium sized all dark
- White pp shafts
- Wings long and blunt
- Tail long and forked
- Flight loping, unhurried
- Deep wingbeats
- Buoyant glides
- Warm waters
- Breeding:
- May-Dec, Islands S. of Japan
- New pop. in N. Atlantic
-
BVSH (Sep-Mar mostly)
- Puffinus opisthomelas
- Small
- Dark brown above
- White below
- Fuzzy edged partial hood
- Near threatened
- Prefers water >57 F
- Breeding:
- Natividad, San Benito, Guadalupe
-
MASH (Mar-May/Aug-Oct)
- Puffinus puffinus
- Like BVSH but:
- Black above
- White undertail is key
- Long body & wings
- Sharp cap edge
- White wraps around ears
- White saddlebags
- Breeding:
- NE & NW Atlantic
-
NESH (One Aug record)
- Puffinus newelli
- Like MASH but:
- Less heavy bodied
- Broader wings
- Shorter tail
- Shorter white UnTC
- Larger saddlebags
- Breeding:
- Hawaii
-
TOSH (Nov-Jun off Baja)
- Puffinus auricularis
- Like BVSH but:
- Blacker above, like MASH
- Sharper edge to dark face
- Further offshore
- Large white saddlebags
- Breeding:
- Revillagigedo Is
-
PFSH (Apr-Oct/Yr round)
- Puffinus creatopus
- Large with broad wings
- Bill pinkish & dark tipped
- Pink feet, graduated tail
- Pale UnW coverts
- Dark UnT coverts
- Partial hood
- Dark flanks on the water
- Rare dark morph
- Breeding:
- Chile
- Juan Fernanadez & Isla Mocha
-
SOSH (Yr round/Apr-Oct)
- Puffinus griseus
- Large
- Narrow pointed wings
- Wingtips curve up
- Short tail
- Silvery UnW coverts
- Fast wingbeats, short glides
- Heaviest wing loading
- Breeding:
- NZ, Australia, South America
-
SRTS (Oct-Mar)
- Puffinus tenuirostris
- Like SOSH but:
- Small slender bill
- Rounder head
- Shorter tail
- Diffuse UnW pale panel
- +/- Pale breast & hooded look
- Rapid swift-like wingbeats
- More buoyant than SOSH
- Arched wings like gadfly
- Wingtips don't curve up
- Breeding:
- South Australia
-
FFSH (Mostly Apr-May & Nov)
- Puffinus carneipes
- Large, all dark
- Bright pink bill
- Like dark morph PFSH
- Can be year round
- Breeding:
- SW Pacific and S Indian Ocean
-
BULS (Jul-Sep)
- Puffinus bulleri
- Blue-Gray w/ bold M above
- Cap & tail darker than back
- All white underwing
- Long wedge-shaped tail
- Leisurely flight
- Often near shore
- Breeding:
- NZ
-
GRSH (Aug-Apr to central Calif)
- Puffinus gravis
- Like PFSH
- Dark above, no M
- Clean dark cap
- Partial-complete white collar
- Dark underwing edges
- Dark ulnar bar
- Narrow white band mid-tail
- Straight narrow wings
- More slender than COSH
- White flanks on the water
- Breeding:
- South Atlantic
-
WTSH (Mar-Apr/Aug-Oct)
- Puffinus pacificus
- Dimorphic
- Dark underwing border
- Long pointed tail
- Pale morph like PFSH but:
- Less bulky
- Larger pointier wings
- Wings often cocked
- Cleaner cut cap
- Found at shelf breaks
- Breeding:
- Tropical Pacific
-
CHSH (Aug-Oct to 180 N)
- Puffinus nativitatis
- Small and all-dark
- Size & flight like MASH
- Flight low, quick wingbeats
- Buoyant glides
- Blunt wingtips
- Medium graduated tail
- Breeding:
- Hawaii and Chile
-
LISH (No records)
- Puffinus assimilis
- Dark above like MASH
- White below like BULS
- Small and compact
- White flanks & rump edges
- White cheeks around dk eye
- Not a long distance migrant
- Breeding:
- NZ, Australia, S Indian Ocean
-
STRS (Aug-Oct to N Calif)
- Calonectris leucomelas
- Like COSH but:
- Scalloped above
- Paler head
- Gray-brown above
- Breeding:
- Northwest Pacific
-
COSH (Any time)
- Calonectris diomedea
- Large, heavy bodied
- Lethargic flight
- Gray-brown above
- Indistinct M
- Thick underwing border
- UnW less marked than PFSH
- Large yellow dk-tipped bill
- White UnT coverts vs GRSH
- White flanks on the water
- Breeding:
- Northeast Atlantic
-
RHAU (Winter)
- Cerorhinca monocerata
- Long stout yellowish bill
- Wedge-shaped head
- Yellow eye
- Gray above and sides
- White belly
- Usually solitary
- Alt: Plumes above & below eye
- Juvenile has dark bill & eye
- Breeding:
- British Columbia to Central Calif
-
CAAU (Year round)
- Ptychoramphus aleuticus
- Small and chunky
- Large head
- White eye, white eye arc above
- Short triangular bill
- Dark gray overall
- Slightly paler belly
- Dark eye in Juv
- Solitary or in groups
- Mostly plankton feeder
- Breeding:
- British Columbia to Baja
-
PAAU
- Aethia psittacula
- Stocky and round-headed
- Upturned circular orange bill
- Broad rounded wings
- Black above and hood
- White belly
- Postocular plume in alt
- Juv has dark eye and bill
- Breeding:
- Alaska
-
TUPU (Migration)
- Fratercula cirrhata
- Alt: Side of face white
- Yellowish rams horn plumes
- Orange bill
- Yellow eye
- Black body
- Basic: All dark
- Slightly paler face
- Smaller orange bill
- Breeding:
- Arctic Alaska to Central Calif
-
HOPU (Feb 1914; Jun 1967)
- Fratercula corniculata
- Alt: Side of face white
- Black throat collar
- Bill yellow with orange tip
- Dark eye
- Thin postocular line
- Vertical supraocular line
- White below
- Basic: Darker gray face
- Bill with dark base, orange tip
- Breeding:
- Arctic Alaska to British Columbia
-
PIGU (Feb-Sep)
- Cepphus columba
- Alt: Black with white GC oval
- Dark notch in oval from below
- Bright red feet
- Basic: White head & below
- Grayer barred back
- Breeding:
- Alaska to Channel Islands
-
COMU (Nov-May)
Uria aalge
- Alt: Dark brown back & head
- White sides & below
- Dark pp ss below
- Dark underwing centerline
- White neck notch in flight
-
Basic: Paler, white cheek
- Drooping postocular line
- Streaked sides
- Dark shoulder
- Breeding:
- Alaskan coast
-
TBMU
- Uria lomvia
- Alt: Like COMU but:
- Black vs brown above
- White gape line
- Thicker shorter bill
- No dark center on underwing
- Breeding:
- Circumpolar along coastlines
-
BRBO (May-Oct)
- Sula leucogaster
- Ad: Dark to gray head
- Dark above
- White below
- Dark wingtips
- Yellow feet & bill
- F: Yellow facial skin
- M: Blue facial skin
- Juv: All dark brown
- +/- pale axillaries
- Dark belly
- Breeding:
- W Mexico, Gulf of California
-
BFBO (Mar-Nov)
- Sula nebouxii
- Ad: Pale head, gray bill
- White scalloping on back
- White patch neck, back, rump
- Pale belly & axillaries
- Mostly dark underwing
- Juv: Dark above with white scalloping
- Dark bill
- Fuzzy edge to hood on chest
- White belly
- Mostly dark underwing
- Pale tail above, dark below
- Breeding:
- W Mexico, Gulf of California
-
RFBO (Yr round)
- Sula sula
- Ad: All white w/ black pp, ss
- White tt
- Pale gray bill
- Dark Ad: Brown w/ blk wings
- Juv: Mostly dark
- Pale belly
- All dark underwing
- Breeding:
- Tropical Pacific
-
NABO (Sep-Oct)
- Sula granti
- Like MABO but in adult:
- Orange to pink bill
- Silver central rects
- Shallower bill
-
MABO (Yr round)
- Sula dactylatra
- Ad: Like RFBO but tail black
- Black pp, ss, and tt
- Juv: Like BRBO Ad F
- White collar, only pp blk
- Pale yellow bill in all
- Breeding:
- Baja, Tropical Pacific
-
NOFU (Oct-May)
- Fulmarus glacialis
- Heavy and bull-necked
- Long, sl rounded, wings
- Yellow bill and feet
- Shearwater-like flight
- Duck-like flaps, then glide
- Wings bowed on glide
- Pale pp bases sometimes
- Dark, intermed, light morphs
- Breeding:
- Arctic
-
RBTR Adult (Aug-Oct/Yr round)
- Phaethon aethereus
- White below
- Black scalloping above
- Black leading wing edge
- White tail streamer
- Rapid parrot-like flaps
- Breeding:
- Western Mexico
-
RBTR Juvenile (Aug-Oct/Yr round)
- Phaethon aethereus
- More finely barred back
- Yellow bill
- Black pp coverts above
- Eye-line meets across nape
- Breeding:
- Western Mexico
-
RTTR Adult
- Phaethon rubricauda
- All white, no black in pp
- (All RBTR WTTR have black pp)
- Black streaks on scapulars
- Curved black eyeline
- No black collar
- Red bill and tail
- Languid wingbeats
- Breeding:
- South Pacific, Indian Ocean
-
RTTR Juvenile
- Phaethon rubricauda
- Black scalloping on back
- No black in pp
- Curved black eyeline
- No black collar
- Black bill on youngest
- Becomes yellow then red
- Languid wingbeats
-
SAGU Adult (Apr-Oct)
- Xema sabini
- Gray-white-black above
- Gray-white-gray on underwing
- Trailing wing edge white
- Black bill with yellow tip
- Buoyant tern-like flight
- Deep wing strokes
- BLKI has shallower strokes
- Breeding:
- Arctic tundra
-
SAGU Juvenile (Apr-Oct)
- Xema sabini
- Brown body and inner wing
- Black tail tip
-
BOGU Adult (Oct-Mar)
- Chroicocephalus philadelphia
- Very small
- White outer wing edge
- Black ear spot in basic
- Black bill, orange legs
- Buoyant flight, angled wings
- Rapid wingbeats
- Breeding:
- Alaska and Central Canada
-
BOGU Juv/1st Winter (Oct-Mar)
- Chroicocephalus philadelphia
- Juvenile:
- Dark brown carpal bar
- Dark pp ss tips
- Black tail tip
- 1st Winter:
- Darker gray body & inner wing
- Narrow dark M above
- Dark pp ss tips
- Black tail tip
- Breeding:
- Alaska and Central Canada
-
BLKI Adult (Oct-Mar)
- Rissa tridactyla
- Light gray above
- Wing tips dipped in ink
- Black legs, yellow bill
- Black smudgy nape in basic
- Buoyant flight
- Shallow wingbeats
- Sharply angled wings
- Breeding:
- Alaska and Arctic
-
BLKI Juvenile (Oct-Mar)
- Rissa tridactyla
- Dark shoulder collar
- Dark bill
- Like non breeding SAGU but:
- Black M above
- Black tail tip band
- Pure white underwing
- Breeding:
- Alaska and Arctic
-
RLKI (no records)
- Rissa brevirostris
- 1st winter like SAGU Basic, but:
- Weaker collar
- Bill shorter, thicker than BLKI
- Dark gray pp below in basic
- No carpal bars on juv
- No black tail tip in juv
- Short red legs
- Winters in Aleutians
- Rare from Gulf of AK to OR
- Breeding:
- Bering Sea
-
LIGU (Nov-May/Yr round)
- Hydrocoloeus minutus
- Like BOGU but:
- Juvenile:
- Dusky cap
- Bold M, dark back
- Dark ss bases
- 1st winter
- Big carpal bar above
- Dusky cap
- Dark ss bases
- +/- pink flush below
- Adult:
- Dusky cap in Basic
- Dark underwing in Alt
- No white leading wing edge
- Fluttery wingbeats
-
ARTE Ad (Apr-May/Aug-Oct)
- Sterna paradisaea
- Lighter above than COTE
- Darker below
- Minimal dark pp edges
- Translucent pp panel
- Shorter bill and neck
- Wings farther forward
- Wings more angular, swept back
- Harder downstroke
- Buoyant flight
- Molts cap south of here
- Longer tail
- Tail longer than wings standing
- Shorter legs
- Bill red, feet orange-red
- Breeding:
- Canada and Alaska
-
ARTE Juv (Apr-May/Aug-Oct)
- Sterna paradisaea
- White UpW
- Faint M above
- Forehead whitish
- Darker 1/2 cap than COTE
- Bill mottled black-red
- Molts south of here
-
COTE Ad (Apr-May/Aug-Oct)
- Sterna hirundo
- Darker above
- Lighter below
- Thicker dark pp edges
- Dark pp panel on UpW
- Longer bill and neck
- Wings further back
- Shorter tail
- Tail and wings even standing
- Molts cap in migration
- Even up and down strokes
- Dark carpal bar juv & basic
- Longer legs
- Both:
- Bill red, feet orange-red
- Breeding:
- Canada and Alaska
-
COTE Juv (Apr-May/Aug-Oct)
- Sterna hirundo
- Dark pp UpW
- Dark carpal bar
- Dark tt line above
- Dark outer rects
- Whitish forehead
- Bill mottled black-red
- Molts south of here
-
ALTE
- Onychoprion anaethetus
- Dark gray above and below
- White forehead
- Black bill and legs
- Shorter tail than ARTE/COTE
- Dark 2o bar on underwing
- Breeding:
- Alaska and Aleutians
-
SPSK (May-Nov; drop in summer)
- Stercorarius maccormicki
- Bulky with lumbering flight
- White pp bases above & below
- Broad, rounded wings
- Glides on bowed wings
- Hunchback look
- Heavier bill than jaegers
- Dark and pale morphs
- No seasonal variation
- Breeding:
- Antarctic
-
MAMU (Nov-Apr)
Brachyramphus marmoratus
- Alt: Dark brown marbling
- Dark underwings
- Dark UnT coverts
- Like ANMU but dark marbled belly
-
Basic: Like SCMU but:
- White cheek wraps to neck
- White scapulars & flank patch
- Dark underwing
- Breeding:
- California to Alaska
-
ANMU (Oct-Nov/Mar-Apr?)
- Synthliboramphus antiquus
- Basic and Alt:
- All gray back
- Black head & chin
- Black axillary stripe
- White belly
- White cheek wraps to neck
- Bright white underwing
- Small pale bill
- Breeding:
- California to Alaska
-
KIMU
- Brachyramphus brevirostris
- Like MAMU but:
- Paler, more golden
- White belly and UnT coverts
- White outer rects
- White above eye in Basic
- Smaller bill
- Juv paler face
- Stays near glaciers
- Breeding:
- Alaska, Aleutians
-
SCMU/GUMU (Feb-Jul/Aug-Dec)
- Synthliboramphus scrippsi
- S. hypoleucus
- Dark back, flanks, sides
- White below gape
- Bright white underwing
- Small dark bill
- GUMU:
- White in front of eye
- Breeding:
- Western Mexico
-
BFAL (Mar-Jul/Year round)
- Phoebastria nigripes
- All dark
- Variable white around bill
- Ad: White tail coverts
- Dusky to dull pink bill
- Blackish feet
- Breeding:
- Is S of Japan to HI
- North to San Benedicto
-
LAAL (Jan-May > Oct-Dec)
- Phoebastria immutabilis
- Black back and wings
- Black tail
- Mostly white below
- Juv: More underwing marks
- Breeding:
- Hawaii to Wake Atoll
- Bonin Island to NW Mexico
-
POJA Ad (Rarer in summer)
- Stercorarius pomarinus
- Large bicolored bill
- Dark cap extends to malar
- Dark jagged breast-band
- Barring on sides
- Double wing flash below
- 4-6 white pp shafts
- Dark UnTC
- Bicolored bill in dark morph too
- Breeding:
- Arctic
-
PAJA Ad (Rare in summer)
- Stercorarius parasiticus
- Slender dark bill
- Dark cap stops at eye
- Smooth grayish breast-band
- Single wing flash
- 3-5 white pp shafts
- Breeding:
- Arctic
-
LTJA Ad (Mainly Sep-Oct)
- Stercorarius longicaudus
- Short bill
- No breastband
- Small neat cap
- Paler overall
- No dark morph
- 2-3 white pp shafts
- No wing flash in adult
- Tern-like flight
- Breeding:
- Arctic & across AK
- Molt to breastband Nov, S of SD
-
PAJA Juv (Rare in summer)
- Stercorarius parasiticus
- Warm brown with rusty edges
- Buff chevrons on outer pp tips
- Wavy bars below except flanks
- Fainter UnT covert bars vs POJA
- Pale nape and malar
- Dark cap pale neck look
- Often pale head
- Streaked face
- Black-tipped gray bill
- Most intermediate morph
- Highest number of dark morphs
- Short pointy central rects
-
LTJA Juv (Mainly Sep-Oct)
- Stercorarius longicaudus
- Much grayer
- Very pale to very dark
- Crisp white barring above
- Straighter bars less scalloped
- Creamy edges above
- Bold neat UnTC/UnWC barring
- Often white chest patch
- Short blunt central rects
-
POJA Juv (Rarer in summer)
- Stercorarius pomarinus
- Less variation than others
- Darker brown and duller
- Usually dark head
- Vague barring on underparts
- Less wavy barring than PAJA
- Strong UnTC barring
- Rarer pale and dark morphs
- Short blunt central rects
-
Juvenile - Immature Jaegers
- Juv cleanest marked in fall
- Older immatures molting in fall
- Brown to gray-brown
- Neat pale barring above
- Scalloping of coverts
- Dark juv sooty all over
- Legs pale (and in Ad LTJA)
- Bill pale at base (and in Ad POJA)
- B&W bars on UpT and UnT coverts
- All have wing flashes below
-
Shearwater Size
- COSH, STRS
- PFSH, GRSH, FFSH, WTSH
- SOSH, SRTS
- BULS
- BVSH, MASH
-
Storm-Petrel Size
- TRSP
- BLSP, MASP, FTSP
- LESP, ASSP
- WISP
- LSTP, WRSP
-
Petrel Size
- PAPE WCPE
- NOFU
- KEPE
- MUPE HAPE GAPE JFPE GWPE HEPE PRPE
- MOPE
- COOP STPE
- PYPE BUPE
-
RNPH (Mar-May, Jul-Oct)
- Phalaropus lobatus
- Alt: Red neck, white throat
- Black head, streaked back
- Thin bill
- Dark above, white pp ss bases
- White below, dark wing edges
- Dark carpal marks on UnW
- Takes off straight up
- Twisting turning flight
- Reversed sexual dimorphism
- Basic: White head
- Thin eye patch
- Gray streaked back
- Darker than REPH
- Breeding:
- Arctic tundra
-
REPH (All but Jun-Jul)
- Phalaropus fulicarius
- Alt: Rusty body
- Dark streaked back
- Black head, white cheeks
- Dark horseshoe collar
- Mostly white underwing
- Takes off straight up
- Twisting turning flight
- Reversed sexual dimorphism
- Basic: Paler than RNPH
- Larger and longer winged
- Thicker bill
- Dark carpus & wingtips above
- Flight call higher, clearer pik
- Breeding:
- Arctic tundra
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