SeabirdsClass: Aves

General Characteristics

● Modern birds are characterized by:○ Feathers○ Laying hard shelled eggs○ Lightweight (but strong) skeleton

■ Hollow bones = efficient for flight○ Homeothermic endotherms○ Scaly legs & claws○ Specialized lungs

■ Air flow in one direction aided by air sacs

General Characteristics

General Characteristics

Flight muscles make up 25-35% of body weight in flying birds!

General Characteristics

General Characteristics

● Birds evolved from reptiles approx. 150-200 mya

● Only 4% of the 9000 species of birds are seabirds○ ~372 species○ Of the 29 orders of birds, 7

contain seabirds

General Characteristics

Seabirds!

● Spend a significant part of their lives at sea and feed on marine organisms

● Most breed in large colonies on land○ 10s to 1000s

● Require lots of food to supply enough energy to maintain body temperatures

● Have salt-excreting glands to allow salt from their diet to drip out of passages on their beaks https://www.youtube.com/watch?v

=FWzOE_WezNg

Seabird Orders

● Sphenisciformes (penguins)● Gaviiformes (divers, loons & grebes)● Procellariiformes (albatrosses, petrels & shearwaters)● Pelecaniformes (pelicans, gannets, boobies, cormorants, &

frigatebirds)● Anseriformes (ducks & geese)● Charadriiformes (gulls, terns and auks)● Falconiformes (sea eagles & ospreys)

Order: Sphenisciformes (penguins)

● 17 species ○ all found south of

the equator● Most found around

Antarctica○ But the

Galapagos penguin lives near the equator

Order: Sphenisciformes (penguins)

Adaptations to the marine environment include:

● Solid (not hollow) bones - great for diving● Hydrodynamic shape - can swim up to 15 mph● Wing bones are fused into a solid flipper - instead of a wing

○ Wings “fly” underwater● Thick fat layer and feathers to insulate● Feathers are denser and pin shaped instead of barbed● Behavioral adaptations (ie. huddling)

Order: Sphenisciformes (penguins)

Order: Gaviiformes (divers, loons & grebes)

● Northern hemisphere’s answer to penguins

Order: Gaviiformes

Adaptations to the marine environment include:

● Solid bones (like penguins)● Heavy enough to sink just by exhaling and emptying air sacs● Feet near the back of the body - Greater thrust for diving● Lobed feet

○ Increased surface area● Dive to depths of 30+ meters for several minutes● Can fly

Order: Procellariiformes (albatross, petrels, & shearwaters)

Albatross

● Do not spend much time in the water○ Fly over the ocean searching for

prey● Usually found in the southern

hemisphere● Glide in the constant strong winds

around Antarctica

Order: Procellariiformes (albatross, petrels, & shearwaters)

Albatross

Adaptations to the marine environment include:

● Long wingspan (3-4 m)● Narrow wings

○ Perfect for long distance gliding● Tube on back of beaks that detects changes

in wind current● Long hooked beak for catching fish

Order: Procellariiformes (albatross, petrels, & shearwaters)

Petrels

● Small sparrow-sized birds

● Skim over the surface of water looking for food

● Migrate to the equator during the winter

● Breed in burrows to avoid predation

Order: Procellariiformes (albatross, petrels, & shearwaters)

Petrels

● Tube on beak (like albatross)● Hooked beak (like albatross)● Secrete excess salt through nose tube● Do not glide as much or as high as A

○ Flap rapidly and stay close to the tops of waves

● Dive into the water or fly through the wave crest

Order: Procellariiformes (albatross, petrels, & shearwaters)

Shearwaters

● Skim surface of water looking for food

● Mostly hunt in the open ocean● Same beak and nose tube as

other procellariiformes

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

● One of the largest groups of seabirds○ 67 species

● Large birds○ Wingspan of up to 3m

Adaptations to the marine environment include:

● All have fully webbed feet● Most have an elastic pouch of skin hanging below their beak

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Pelicans

● Very thin, hydrodynamic shape○ Great for diving into the water

● Open their mouths and use their throat pouches to “net” their prey

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Boobies

● Primarily tropical● Dive from heights of nearly

100’ onto prey● Torpedo shaped

○ Great for piercing surface of water

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Gannets

● Found in cool northern regions● Nest on rocky cliffs● Dive onto prey from height, like

boobies● Hit the water at 60mph

○ Adaptations to absorb the force of impact and protect brain

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Cormorants

● SUPER streamlined for diving from heights

● Can dive to depths of 10m+● Some species are flightless

with large webbed rear feet● Wings are not waterproof

○ Must land to allow wings to dry

Order: Pelecaniformes (pelicans, boobies, gannets, cormorants, & frigatebirds)

Frigatebirds

● Large wing span○ Built for gliding○ Can stay airborne for months at a time○ Not waterproof

● Opportunistic feeders○ Mollusks, fish, turtles, and even

jellyfish○ Steal food from other seabirds

Order: Anseriformes (ducks & geese)

Ducks

● Eider and Steamer Duck● Soft, fluffy feathers

○ Well insulating● Eat molluscs & crabs whole

○ Remove claws and legs of crab before eating

○ Shells crushed up in the gizzard● Some species flightless while others are not

Order: Anseriformes (ducks & geese)

Geese

● Kelp goose○ Year round residents of

the Falkland Islands○ Feed on algae

Order: Anseriformes (ducks & geese)

Order: Charadriiformes (gulls, terns, skuas, & auks)

● Account for nearly half of the seabird species○ 131 species

● Including:○ 50 species of gulls○ 44 species of terns○ 22 species of auk○ 8 species of skua

Order: Charadriiformes (gulls, terns, skuas, & auks)

Gulls

● Hooked beaks, webbed feet and long powerful wings

● “Jack of all trades”○ Can dive, fly, and “swim” like other seabirds

but not as well● Opportunistic feeders

○ Able to find a niche in almost any open ocean or coastal environment

Order: Charadriiformes (gulls, terns, skuas, & auks)

Order: Charadriiformes (gulls, terns, skuas, & auks)

Terns

● Sometimes called “sea swallows”○ More graceful relative of gulls

● Hunt for food rather than scavenge like gulls

● Only have small webbed feet○ Not great swimmers○ Swoop and catch prey

Order: Charadriiformes (gulls, terns, skuas, & auks)

Skuas

● Also called Jaegers● Look like a cross between a hawk

and a gull● Fierce predators● Most inhabit the southern

hemisphere○ Great skua found in northern

hemisphere

Order: Charadriiformes (gulls, terns, skuas, & auks)

Auks

● Clumsy fliers but good divers● Usually inhabit colder, northern hemisphere areas● Narrow, parrot like beak

○ Used to scoop up small fish several at a time● Use wings to fly underwater (like penguins)● More buoyant than penguins

○ Have to work harder to stay underwater

Other Birds Found in the Marine Environment

● Herons, Egrets & Spoonbills○ Freshwater, but also seen in salt marshes and estuaries

● Flamingos○ Live in salt marshes and estuaries - filters brine shrimp out

of the water● Kingfishers● Crows

○ Especially the fish crow ● Sea Eagles & Ospreys