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SCI-04 Natural History of
Alaskan Seabirds
• Session 3: Tuesday, 15 March 2016
• Today’s Topics
– “Waterbirds” concluded (Loons)
– Grebes
– Gulls
– (Terns, Jaegers: next session)
–
Order GAVIIFORMES
Family Gaviidae: Loons
• 5 species, both worldwide and in
Alaska
• large, heavy, foot-propelled divers
• spear-shaped bills
• legs positioned far back on the body
• difficulty moving on land
• Diving: reach depths of 75 meters
and stay underwater to 8 minutes
• young ride on their parents’ backs
when small
• long-lived, to 28 years
• pair monogamously, typically for life
Pacific Loon
Gavia pacifica
• Breeding adult:
– Head and nape pale gray
– White stripes on sides of neck
– Throat patch iridescent purple
• Vs Arctic Loon: Little or no
white on flanks when sitting
on water
• Breeding distribution: NE
Sibera to Hudson Bay
• Winters along Pacific coast
to Baja CA
• Numbers
– Alaska: 100,000-125,000
– Wintering areas: 1 million
Arctic Loon, Gavia arctica
• Breeding range:
Scandinavia to western
Alaska
• No interbreeding with
Arctic Loon where
ranges overlap (NE
Sibera, W Alaska)
• In Pacific, winters
along Asian coast
• White on flanks of both
immatures and adults
Pacific and Arctic Loons
• How, when did speciation
occur?
• Period of geographic
separation (allopatry)?
• Ice sheets at Last Glacial
Maximum (~18,000 years ago)
Red-throated Loon, Gavia stellata
• Circumpolar distribution
• Smallest loon
• Breeding adult:
– Pale gray head
– Distinct red throat patch
• Only rarely breeds far inland
• Only loon to commute between nesting
pond and ocean or larger lakes to feed
• Winters along northern sea coasts
• Numbers:
– Alaska: 10,000
Common Loon, Gavia immer
• (Tasingik = black-billed)
• From Swedish: “lame”
• Breeding adult:
– black head
– Necklace
• Breeding range: Boreal biome
of North America to Iceland
• Winter: northern coastlines to
Scandinavia
• Note shape of bands on legs
Common Loon
• Numbers:
– Alaska: 10,000
– Worldwide (NA): 250,000
• Demography
– Age at 1st breeding: 6 years
– Average breeding success: 0.5
fledglings
– Annual survival: 92%
– Average lifespan: 30 years
– TYPICAL FOR LARGE SEABIRDS
Yellow-billed Loon, Gavia adamsii
• Inupiat: Tootlik
• Bill: Straw-yellow bill
• Breeding adult:
– Black head, necklace
• Breeding range: Central Canadian
Arctic to northern Siberia
• Winter range: Northern coastlines,
Pacific and Atlantic
• Rare
– Alaska: 2,400
– Worldwide: ?
– VIDEO:https://www.youtube.com/watch?v=
kyRTu-VJM1Q
Yellow-billed Loon territoriality
• Pairs exclude both other Yellow-billed
Loons and Pacific Loons from their
territories
• Graph: Numbers vs. Lake size on Colville
River, Alaska
– Note: Toolik Lake is 150 ha.
– Interpretation: Pacific Loons co-occur on lakes
with Yellow-billed Loons only if lakes are large
with convoluted shorelines
• Source: Haynes, T. B., et al. 2014. Journal
of Avian Biology 45:296-304.
Order PODICIPEDIFORMES
• GREBES
• 1 family (Podicipedidae), 6
genera, 19 species
• Lobed, NOT webbed, toes
• Floating nests
• Parents carry their young on
their back, even when diving
Horned Grebe, Podiceps auritus
• Small
• Breeding adult (1 year-old plus):
– Red eyes
– golden horns back and above the
eye
• Distribution
– Circumboreal
– Breeds on small ponds and lakes
(e.g., Smith Lake)
– Winters along seacoasts (and inland
water bodies in SE US)
• Numbers
– North America: 200,000
– Eurasia” ?
Red-necked Grebe
Podiceps grisegena
• Circumboreal
• Breeding adult:
– Light gray cheeks
– Reddish throat
– Dark crown
• Breeds on inland lakes
• Winters along sea coasts
• Numbers:
– Alaska > 12,000
– Worldwide: ?
Flightlessness in Grebes
• 2 flightless species:
– Titicaca Grebe (Lake
Titicaca and nearby
ephemeral lakes in wet
years)
– Junin Grebe: Lake Junin,
West central Peru only
– These 2 species are
placed in different genera
Charadriiformes: Phylogeny
• 17 families, 360
species
• Shared, unique
features of skull,
vertebral column,
and syrinx
• “Shorebirds and
relatives”
• Closest relatives:
“Land birds”
“Seabird” subgroups
• Scolopaci
– Phalaropes
• Lari
– Gulls and Terns
– Skuas and Jaegers
– Auks
Phalaropes
• Reversed sexual
dimorphism
– Females larger,
showier, and
compete with each
other for mates
• Sex role reversal:
females never
incubate
Phalaropes
• Non-territorial
• Females compete directly for male mates
• Once paired, a female produces a 4-egg
clutch which that mate then incubates on his
own
• Female may then return to display area and
attract a second mate, repeating the
process
• OR female may produce a 2nd clutch for 1st
mate if 1st clutch is lost to predation
• OR BOTH
Phalaropes at Sea
• Pelagic
• Foods include copepods (small
crustaceans)
• Red Phalarope Red-necked Phalarope
Phalaropes as seabirds
• Chukchi Sea
– >500,000 Red
Phalaorpes (REPH)
– 25% of all seabirds
– vastly outnumber
plantivorous auklets
(6%)
– Diet: Copepods
– Lower graph
• Left panel: oceanic
copepod numbers
• Right panel Calanus
marshallae numbers
Copepods
• Small crustaceans
– Planktonic or
benthic
– Free-living or
parasitic
– Unbelievable
morphologies
– Source:
– Ernest Haeckel, Art
forms in Nature.
1904
– https://en.wikipedia.org/wiki
/Kunstformen_der_Natur
Calanus copepods
• Exceptional abundance in
Bering and Chukchi Seas
• C glacialis: 80% of zooplankton
in arctic waters (ice edge
blooms)
Laridae (part): Gulls
• Large diverse group with
strong wings and powerful
flight
• Only several highly
pelagic, most coastal,
some inland
• No large Larus gulls on
the Pribilof Islands
• 2-4 years to achieve adult
plumage and maturity
• Immatures often difficult to
identify
• Many nest colonially
Black-legged Kittiwake
Rissa tridactyla
• Medium-sized, cliff-nesting gull, a
true “sea gull”
• yellow bill
• Black legs, dark eyes
• Gray mantle, wing tips dipped in
black
• Subarctic to Arctic, Circumpolar
• About 2.5 million in Alaska,
breeding wherever suitable sea
cliffs occur
Black-legged Kittiwakes: Numbers
• Most-studied cliffnesting seabird
species in Alaska
• Numerous colonies:
many years of counts
• Trends: highly
variable among
colonies
Black-legged Kittiwakes:
When to count?
• Numbers most consistent after all
females have laid eggs and before
any chick have fledged (one parent at
nest, one at sea): counts should be
during this period
• Graph: Seasonal pattern of numbers
(Semidi Islands, Hatch and Hatch 1988)
Black-legged Kittiwakes:
breeding success
• Maximum clutch
size: 3 eggs (VERY
rare in Alaska, some
years: zero)
• Success ranges from
0 to 2 fledglings and
varies markedly
among years
• Example: Bluff, a
colony in Norton
Sound
• WHY? ________
Black-legged Kittiwakes: foods
• Sand lance (red): Coastal
colonies in Gulf of Alaska
to Chukchi Sea
• Gadids (cods, purple):
Bering and Chukchi Seas
• Myctophids (light blue):
Pribilof Islands only
• Annual variation:
EXTREME
• Poorly understood since
no commercial fisheries
on these fishes
Brood reduction
• Laying strategy: Lay number of
eggs that will be successful in
a good year
• Incubation strategy: create
inequities in case it’s not a
good year
• Late-hatched chicks: smaller,
can’t compete for meals when
food is limited
• If die quickly, more food for
other young
• How to promote quick death in
years of food shortage?
Siblicide in seabirds
• Facultative (kittiwakes):
– NO: if food is abundant and
larger older chick is fat and
happy—rare in Alaska, though
– YES: if larger older chick isn’t
getting full meal deals
• Vs. “Obligate (pelicans):
– Older larger chick always kills
smaller younger chick
– Why lay 2 eggs? Insurance if
1st does not hatch
– Lower photo: American White
Pelican
Red-legged Kittiwake, Rissa
brevirostris
• Red legs
• Vs Black-legged:
– Bill relatively short
– Mantle darker gray
– Black on wing tips not a
distinct line
– Eyes larger
• ~200,000 (“Special
Concern”)
• VERY restricted
breeding distribution
– 80% on St. George Island
Red-legged Kittiwakes: Prey
• Broad overlap with Blacklegged Kittiwakes, BUT
• Lanternfish (family
Myctophidae) much more
important in diet
– Bioluminescent
– Diel vertical migrations, near
surface at night
– Exceptionally high
abundance in continental
slope zone near St. George
Island
Red-legged Kittiwakes:
nest site preference
• “Character
(competitive)
displacement”:
key component
of niche that is
not exploited by
superior
competitor.
• Prefer narrow
ledges at high
elevations
Ivory Gull
Pagophila eburnea
•
•
•
•
All white body
Bi-colored, yellow-tipped bill
Black eyes, black legs
Most arctic of all birds; scavenger on arctic
pack ice; global warming threat?
Sabine’s Gull
Xema sabini
•
•
•
•
Small gull
Black-white-gray wing pattern
Slightly forked tail
Breeding adult
– Dark gray (black) hood
– Bill black with yellow tip
• Breeds in arctic coastal
tundra regions
• Winters in coastal upwelling
zones in tropics, subtropics
Any “sea gulls” in Fairbanks?
•
•
•
•
Yes? ____
If yes, how many species? ____
No? ___
Note proper terminology: “gull”, NOT “sea
gull”
Bonaparte’s Gull,
Larus philadelphia
• Small gull
• Breeding adult
– Black hood
– Black bill
– Gray mantle with black wing
tips
– Orange-red legs
• Nests in black spruces
• Only “obligate” tree-nesting
gull
• In Alaska, breeds throughout
boreal forest zone
• Winters along NA coasts
Ross’s Gull
Rhodostethia rosea
•
•
•
•
Small-bodied
Variably light pink below
Small black bill
Breeding adult: thin black
collar, orange legs
• Breeds in Russian Far East;
Winters in northern Alaskan
waters
• Focus of ecotourism at
Barrow, late September-midOctober; WHY? ____
Ross’s Gulls in Fall
• Chukchi Sea Lease Area
• Entire Siberian
population of Ross’s
Gulls passes by
Barrow, first to east
and then to west
• Only brief stay in
Beaufort Sea
• Recall offshore oil
lease zones
Ross’s Gulls: worst-ever specimens?
• First specimens of this species at the US
National Museum (Smithsonian)
– Collected soon after Jeanette became mired in
the ice (7 October 1879)
– Carried until finally rescued more than 2 years
later in northern Siberia by naturalist and
taxidermist: Raymond Lee Newcomb
Mew Gull, Larus canus (Nauygavak
= beautiful gull)
•
•
•
•
•
Medium Size
Small, all-yellow bill
Yellow legs
Wing tips splotched with black
In Eurasia: Boreal zone,
called “Common Gull”
• In Alaska, breeds from crest
of Brooks Range south
• Common in Fairbanks in
summer
• Winters along Pacific coast
•
•
•
•
•
Herring Gull
Larus argentatus
Large body
Pale gray mantle
Pink legs and feet
Bill yellow with red spot
Circumboreal breeding
distribution
– Common in Fairbanks in
Summer
• Winters along coasts and
inland
Thayer’s Gull
Larus glaucoides
• Iceland Gull Subspecies
thayeri
• Breeding adult
–
–
–
–
Eye dark brown
Bill yellow with red spot
Mantle light gray
Legs dark pink
• Alaska: Coastal migrant only
between NE Pacific coast
and High Canadian Arctic
• Some winter in polynyas
Slaty-backed Gull
Larus schistisagus
• Breeding adult:
– Dark, slate-gray back
and wings
– Legs bright pink
– Bill yellow with red spot
– Eyes pale
• Eurasian; breeding
range extends to
southern Seward
Peninsula in Alaska
Glaucous-winged Gull
Larus glaucescens
• Breeding adult:
– Mantle pale gray
– Above: primaries same color as
rest of wing
– Below: primaries lighter
– Eyes DARK
– Legs pink
– Bill large, yellow, with red spot
• In Alaska, breeding range
extends north to central
Bering Sea
• Winters along Pacific coast to
Baja CA
Glaucous Gull,
Larus hyperboreus
• Large-bodied
• All plumages: primaries white
with translucent tips (all white
distally)
• Breeding adults:
–
–
–
–
all white to light gray;
Eyes YELLOW
Legs pink
Bill large, yellow, with red spot
• Breeds along coast of
western and northern Alaska
and inland on North Slope
• Winters along northern sea
coasts and on Great Lakes