Finally, we must include raptors, particularly the peregrine (Falco peregrinus) and bald eagle (Haliaeetus leucocephalus), because they are important predators on the smaller seabirds (White et al. 1971, 1973). Peregrines have, in fact, been observed feeding on storm-petrels far at sea (Craddock and Carlson 1970).

Trophic Relations Within Seabird Communities

We have compared and summarized in general terms the food partitioning by species in five rather broad oceanographic regions and their subdivisions in the northeastern North Pacific and Bering Sea, based on the specific details on diets presented in Tables 1 through 10. The five broad regions, defined oceanographically by Dodimead et al. (1963) and Favorite et al. (1976) and modified by Sanger (1972), are shown in Fig. 1. The five oceanographic regions (domains) were divided further into inshore neritic, offshore neritic, and oceanic habitats (Sanger and King, this volume). We did not include estuarine habitats or sheltered bays in the analysis.

Fig. 1. Schematic oceanographic domains of the subarctic Pacific regions (defined by Dodimead et al. (1963) and Favorite et al. (1976) and modified by Sanger (1972).)

Table 4. Food of murres and puffins in different localities (x = major prey, o = minor prey, and * = incidental prey species).
LOCATIONDiet
CRUS­TA­CEANP
O
L
Y
C
H
A
E
T
E		C
E
P
H
A
L
O
P
O
D		FISH
E
u
p
h
a
u
s
i
i
d		A
m
p
h
i
p
o
d		I
s
o
p
o
d		D
e
c
a
p
o
d		C
l
u
p
e
a		S
a
r
d
i
n
o
p
s		E
n
g
r
a
u
l
i
s		S
a
l
m
o		O
n
c
h
o
r
h
y
n
c
h
u
s		H
y
p
o
m
e
s
u
s		T
h
a
l
e
i
c
h
t
h
y
s		M
a
l
l
o
t
u
s		B
o
r
e
o
g
a
d
u
s		M
i
c
r
o
g
a
d
u
s		T
h
e
r
a
g
r
a		L
y
c
o
d
e
s		G
a
s
t
e
r
o
s
t
e
u
s		S
e
b
a
s
t
e		T
r
i
g
l
o
p
s		M
y
o
x
o
c
e
p
h
a
l
u
s		C
o
t
t
i
d		C
y
m
a
t
o
g
a
s
t
e
r		E
m
b
i
o
t
o
c
i
d		C
h
i
r
o
l
o
p
h
i
s		S
t
i
c
h
a
e
i
d		A
m
m
o
d
y
t
e
s		P
l
e
u
r
o
n
e
c
t
i
d		L
i
p
a
r
i
d
Common murre(Uria aalge)[20]
Cape Thompson (Swartz 1966)oooooxooox
Pribilof Islands (Preble and McAtee 1923)xooo
E. Bering Sea (Ogi and Tsujita 1973)xoxxx
Forrester Island (Heath 1915)oox
Vancouver Islandooxo
(Robertson, unpublished data)xxoo
Olympic Peninsula (Cody 1973)xxoxooo
Yaquina Headxo
(Scott 1973)xoo*xoo
Farallon Islands (PRBO, unpublished data)xo
Thick-billed murre
(U. lomvia)[21]		xoooooxo
Cape Thompson (Swartz 1966)ooo
Pribilof Islands (Preble and McAtee 1923)xx
Hooker Islandxo
(Demme 1934, in Dement'ev et al. 1968)ox*x*oxooo
NE Canada (Tuck and Squires 1937)xooo
Tufted puffinx
(Lunda cirrhata)[22]*
Cape Thompson*
(Swartz 1966)x
Forrester Island (Heath 1915)x
Langara Islandx
(Sealy 1973a)xxxx
Washingtono
(Jewett et al. 1953)xox
Olympic Peninsulax
(Cody 1973)xo
Farallon Island (PRBO, unpublished data)x
Horned puffinxo
(Fratercula corniculata)ox
Cape Thompson (Swartz 1966)o
Alaska (Bent 1946)x
Forrester Island (Heath 1915)
Rhinoceros auklet (Cerorhinca monocerata)xoxx
NW Pacific (Kozlova 1961;x
Komaki 1967)x
Forrester Island (Heath 1915)x
Langara Island (Sealy 1973a)ox
Destruction Islando
(Richardson 1961)xxo
Olympic Peninsula (Cody 1973)x
So. California (Linton 1908; Grinnell 1899)x
Table 5. Food of ancient and marbled murrelets (x = major prey, o = minor prey, and * = incidental prey species).
LocationDIET
CRUSTACEANSQU­IDFISH
Eu­phau­si­idThy­sa­noes­saEu­phau­siaMy­sidA­can­tho­my­sisAm­phi­podGam­ma­ridCa­rid shrimpDec­a­podLar­vaeLar­vaeEn­gra­u­lisOs­mer­idScor­paen­idCy­ma­to­ga­sterSti­chae­idAm­mo­dy­tesLar­vae
Ancient murrelet (Synthliboramphus antiquus)[23]
Commander Islands (Dement'ev et al. 1968) xx
Amchitka Island (White et al. 1971, 1973)x x x x x
Langara Island (Sealy 1975)x x x * * * o o x
Marbled murrelet (Brachyramphus marmoratus)[24]
SE Alaska (Grinnell 1897) o
Langara Island (Sealy 1975)x x * * * * x *
Vancouver Island (Munro and Clemens 1931) x x x
Olympic Peninsula (Cody 1973) x x
Table 6. Diets of auklets in different localities (x = major prey, o = minor prey, and * = incidental prey species).
LocationDiet
CRUSTACEANPO­LY­CHAE­TESQUIDFISH
Eu­pha­u­si­idThy­sa­noes­saMy­sidSty­lo­my­sisAm­phi­podPa­ra­the­mi­stoPhro­ne­maGam­ma­ridCo­pe­podCa­la­nusCa­rid shrimpLar­vaeCot­tidLar­vae
Cassin's auklet (Ptychoramphus aleuticus)
Forrester Island (Heath 1915)x x x
Olympic Peninsula (Cody 1973)x x
Farallon Islands (Manuwal 1974)x x x x x o x
Parakeet auklet (Cyclorrhynchus psittaculus)
Chukhotsk Peninsula (Portenko 1934, in Dement'ev et al. 1968)xx x x x
Aleutian Islands (Bent 1946) x
St. Lawrence Island (Bédard 1969a) x x ox xo o * o o o
Crested auklet (Aethia cristatella)[25]
W. Bering Sea (Portenko 1934, in Dement'ev et al. 1968)x x
Commander Islands (Stejneger 1885) x
Amchitka (White et al. 1973)x x x x x
St. Lawrence Island. (Bédard 1969a) x x xo o x x*
Pribilof Islands (Preble and McAtee 1923) x x
Least auklet (A. pusilla)
Commander Islands (Stejneger 1885) x
Aleutian Islands (Bent 1946) x
St. Lawrence Island (Bédard 1969a) o o * ooo x x x
Whiskered auklet (A. pygmaea)
Commander Islands (Stejneger 1885)x x *