Shorebirds vs. Seabirds & Bird Species
Birds that have adapted to life at sea spend their lives in the air above the surface, in the upper layers of the open ocean, or
along shorelines. Shorebirds (birds that live and feed on the coastlines) rarely range far from land. These include wading
birds, such as herons and cranes, and gulls. Seabirds, on the other hand, are pelagic, often remaining at sea for months
on end and retuning to land only to breed. Unlike land birds, many pelagic sea birds breed in large colonies on islands and
cliffs, deserting them when the breeding season ends.
A. Anatomy:
There is no such thing as a typical sea bird, although pelagic birds share many adaptations for life at sea. These include
webbed feet, highly waterproof plumage, and glands that get rid of excess salt. Most land birds have hollow, air-filled bones
that help to save weight, but in diving species, such as penguins, the bones are denser and the air space reduced. Some
plunge-divers, including gannets and pelicans, have air sacs under their skin. These cushion the impact as they hit the water
and help them to bob back to the surface with their prey. Compared to these marine species, shorebirds show few specific
adaptations for life in or near salt water but, like all birds, they have bills specialized for dealing with different kinds of food.
B. Adaptations of Seabirds:
Seabirds are well adapted to life in a marine environment, and they have several physical adaptations that give
them an advantage for life on the high seas. Knowing these adaptations can help birders instantly recognize if they
are looking at a seabird.
a. Plumage Coloration: Most seabirds have drab plumage that is dark above and light below. This type
of coloration, called countershading, offers camouflage from aerial predators and hides the bird from
potential prey beneath them.
b. Feathers: Seabirds have more feathers relative to their body size than other birds, which gives them
superior waterproofing and insulation. Some seabird species have even more specialized feathers to
help with buoyancy or additional insulation, such as penguins' dense feathers that protect them from
Antarctic temperatures.
c. Feet: Most seabirds have flexible webbed feet that help them be powerful swimmers or help propel
them across the water to gain speed for takeoff. Some species have strong claws on their feet to help
with fishing as well.
d. Wing Shape: Seabirds' wings are specially shaped for their unique flight needs. Longer, more tapered
wings allow seabirds to soar for hours with very little effort, allowing them to remain aloft far from
land. In some species, shorter wings give the birds better control and agility for flight right at the
surface of the water.
e. Salt Glands: Many seabirds have specialized salt glands that extract salt from the birds' food and water,
allowing them to eat and drink without dehydration from too much salt. Excess salt is then excreted,
typically near the birds' nostrils.
f. Head Structure: Seabirds that hunt deeper in the water through plunge diving, such as gannets, have
specialized adaptations in their head structure to withstand high speed impacts with the water such as
strong, tapered bills, air sacs and thicker bones.
C. Seabird Behavior
Because of their unique environment, seabirds act uniquely. Understanding the unique behaviors of seabirds can help
people appreciate these marine birds.
a. Diet: Because of where they live, seabirds subsist on a diet of primarily fish, squid and crustaceans.
Many seabirds will mob fishing boats in search of easy food from discarded fish and offal, and seabirds
have also been known to forage through trash dumped at sea.
b. Flight: Most seabirds are powerful fliers with the ability to soar without effort on their long wings. The
gliding, soaring flight of seabirds can be easily recognized, though smaller types of seabirds do have
more energetic and erratic flight patterns.
c. Breeding: Unlike the solitary breeding preferences of many bird species, seabirds are colonial nesters
and a breeding colony may grow to thousands of birds. Most seabirds nurture their young for much
longer than typical land birds, and it is not unusual for a seabird fledgling to remain with its parents for
several months at sea. Because of this long parental care period, most seabirds raise only one brood per
year, and that brood is often just a single egg.
d. Lifespan: While a typical songbird may live just a handful of years and a bird older than 10 is unusual,
seabirds have much longer lifespan. Many seabirds do not fully mature until they are several years old,
and a lifespan of 20-40 years is not uncommon.
D. Bill Adaptations
Apart form waterfowl, most birds of the sea and shore are carnivores, with bills that are adapted for different kinds of
animal prey. A pelican’s bill and pouch work like a scoop, while an albatross’s hooked bill can grip slippery prey, such
as jellyfish. Sea eagles catch their prey with their talons, but then use their bills to tear it into pieces. Curlews have long
bills that can probe for animals buried in mud.
E. Habitats
Birds live throughout the world’s oceans and shorelines, from the equator to the poles. Less than 200 species are truly pelagic.
Although they feed on sea animals, their true habitat is the air. Food is widely scattered in the open oceans, which is why the
majority of sea birds live closer to land. Most diving sea birds feed in the shallow waters over continental shelves, while rocky
coasts and mudflats are key habitats for waders and gulls. Estuaries are important habitats for coastal birds. Their muddy silt often
harbors numerous worms and mollusks, accessible at low tide. In the tropics, mangrove swamps attract birds for the same reason;
they also have the added bonus of trees, in which birds nest and roost.
F. Feeding methods:
Marine birds have evolved several ways of hunting their food.
a. Plunge divers – birds such as brown pelicans, which slam into shoals of fish from heights of up to 100
ft. Diving sea birds also include many that operate from the surface, such as cormorants and penguins.
b. Many oceanic birds, such as albatrosses and petrels, hunt on the wing, snatching animals or scraps from
the surface. Some birds, such as frigate birds, harass other birds into releasing their catch.
c. Coastal birds often probe for food in the shallows or along the tide line.
d. Skimmers slice through the water, holding their lower bill underwater while in flight, but this
technique works only if the surface is flat and calm.
G. Dispersal and Migration
Marine birds can range over a huge distance in their lifetime. Some disperse over wide areas of ocean, returning to
isolated colonies to breed. Many other birds migrate between distinct summer and winter ranges.
Marine Birds Species
Gulls
Herring gulls are noisy, assertive, and always on the lookout for a meal. This is the most
widespread gull in the Northern Hemisphere. It has gray upperparts and black wingtips, and a
large yellow bill with a red spot near the tip. They are highly adaptable birds, feeding on
anything edible that they can find. They rarely venture far out to sea, but their range extends a
long way inland.
Laughing Gulls are summer visitors to the Gulf Coast. If feeds mainly by scavenging and
often follows ferries and fishing boats. During breeding season, it’s head turns a dull white.
The solid colored, dark head feathers of the Laughing Gull (Leucophaeus atricilla) in summer
plumage, often described as a hood, makes is difficult to mistake it for any other North
American Larus species. The picture shows the Laughing Gull in winter plumage, with a
prominent white eye ring and dark legs and a minimal dark patch of feathers on an otherwise
white head.
Yellow legs and a black ring around a yellow bill distinguish the Ring-billed Gull (Larus
delawarensis) from other Larus species. It's one of the more common gulls in the United
States, wintering in the southern part of the United States from coast to coast. During breeding
season, large flocks migrate to the northern tier of the United States and Southern Canada.
The name delawarensis stands for the place the species was first recorded, the Delaware
River.
Ring-billed gulls serve to remind us that sometimes the term sea gull is a misplaced
description of the genus. Many individuals spend the majority of their summer and winter lives far away from salt water habitats.
American Oystercatcher (Haematopus palliatus)
The American oystercatcher reaches a height of 17 to 21 inches (43 to 53 cm), with a 35inch (89 cm) wingspan. Other distinguishing characteristics include an orange bill 3 to 4
inches (7.5 to 10 cm) long, thick pink legs, bright yellow eyes with red rings around them,
black or dark brown backs with black heads and necks, and white bellies and breasts and
white stripes on their wings. The genus name Haematopus is Greek for "blood foot", and
refers to the oystercatcher's pink legs. Palliatus means "cloaked" in Latin, and refers to
the black "cloak" of feathers on its head.
This common shorebird eats oysters, clams, barnacles, starfish, crabs, jellyfish, limpets, chitons, marine worms, and other
invertebrates. The bird's long orange bill is shaped like a knife. It uses its beak to pry open oysters and other bivalves for food,
hence the name "oystercatcher". When an American oystercatcher pries an oyster shell open, it quickly clips the bivalve's
adductor muscle (the muscle that holds its shell shut). The bivalve cannot protect itself by closing its shell and is eaten by its
predator. Oystercatchers that feed mainly on animals in the soft sand or mud have a more pointed bill than oystercatchers that
feed on rocky shorelines. Because they live and feed on the seashore, salt builds up in oystercatchers' blood from the salty
water. Special glands help the birds drain excess salt out of their system.
Oystercatchers are very protective of their young. Both parents incubate the eggs. To disguise the speckled eggs, the adults
add broken shells or pebbles to the nests. To distract predators, adult birds will fake an injury to attract attention away from the
nest or pretend to brood where there is no nest.
The black oystercatcher (Haematopus bachmani), the American oystercatcher's cousin, is endemic to (or found only on) North
America's Pacific Coast.
The American oystercatcher is an easily recognized shorebird that makes its home on the beach or near salt marshes and
mudflats. During the eighteenth and nineteenth centuries, American oystercatchers were hunted for food and their plumage.
When the species became protected under law in 1918, it was near extinction along the Atlantic Coast. Its numbers are now
increasing throughout its range. However, as cities and towns grow along beaches in North America, oystercatchers have
fewer available nesting areas.
Brown Pelican (Pelecanus occidentalis)
Brown Pelican
Endangered
Endangered, Listed 10/13/1970
DESCRIPTION
The brown pelican has an 18-inch long bill and large throat pouch. Its head is white in front and
dark brown behind, extending down the neck and back. During the breeding season, the white
plumage turns a vibrant yellowish-gold color. Silver-gray feathers cover the rest of the pelican's
body. The brown pelican weighs about 9 pounds and has a 6-foot wingspan.
LIFE HISTORY
When feeding, pelicans soar in the air looking for fish near the surface of the water. It feeds by plunge-diving. When a fish is
spotted, the pelican goes into a dive, plunging 30 to 60 feet bill-first into the water. The impact of hitting the water would kill an
ordinary bird, but the pelican is equipped with air sacs just beneath the skin to cushion the blow.
The loose skin on the underside of the bill extends to form a scoop net with an amazing capacity of 2.5 gallons. The pelican
drains the water from its pouch and tosses its head back to swallow the fish. Their diet consists of menhaden and mullet fish.
They lay 2 to 4 white eggs during breeding season, and live up to 30 years or more. Young pelicans are fed for about 9
weeks. During this time, each nestling will eat about 150 pounds of fish.
OTHER
Pelicans almost disappeared from Texas because they were poisoned by the pesticide DDT, which caused them to lay thinshelled eggs which broke during incubation. Because they were not able to produce young, the number of pelicans dropped to
less than 100 birds during the years 1967-1974. Since DDT was banned in 1972, pelicans have made a steady comeback.
Long-billed Curlew (Numenius americanus)
DESCRIPTION
The long-billed curlew reaches a height of 18 to 26 inches (45 to 66 cm), with a 36- to 40-inch
(91 to 101 cm) wingspan. They have speckled brown and buff backs and upper wings, buff
colored bellies and breasts, and cinnamon-colored under wings. Their legs and feet are bluishgray, and the feet have webbed front toes. The long, thin, down-curved bill is dark and fades
to a flesh tone at the base. Its bill can be more than 8 inches (20 cm) long and has a dropletshaped tip.
LIFE HISTORY
When inland, long-billed curlews eat mostly insects and worms. In coastal areas, they probe in
the mud with their long bills for shellfish, crabs, and fish. They will also eat other nesting birds. Predators hawks, badgers,
coyotes, weasels, and snakes feed on long-billed curlews. Nests are built on the ground in flat, open areas with clumps of
grass. The nests are simple depressions in the ground, usually lined with grass. Curlews frequently build nests near cow
patties or bushes to help hide the nests from predators. Long-billed curlews can swim if they need to - their front toes are
webbed. They can fly as fast as 50 miles (80 km) per hour.
Roseate Spoonbill (Platalea ajaja)
DESCRIPTION
Roseate spoonbills grow to a height of 32 inches (81 cm), with an average
wingspan of 50 inches (127 cm). Their distinguishing characteristics include their
pink body and legs, white neck and breast. pale green bald head, spoon-shaped
bill, and bright red shoulder patch.
LIFE HISTORY
Roseate spoonbills eat primarily small fish and crustaceans. Raccoons and coyotes eat
roseate spoonbill eggs and young. Their life span is as long as ten years.
Unlike most birds, roseate spoonbills are silent and often solitary when they feed. They swish their spoon-shaped bills back
and forth in the water to find small invertebrates, fish and crustaceans. Spoonbills eat shrimp, shrimp eat algae, and the algae
make their own red and yellow pigments, called carotenoids. Some scientists believe that the pink coloration that roseate
spoonbills acquire as they mature is due to their diet of carotenoid-rich organisms like shrimp. The more they eat, the pinker
they get. Flamingos are close relatives of the roseate spoonbill. They both have pink feathers, but the flamingos are much
larger, with a longer neck.
OTHER
Like many other bird species with beautiful plumage, roseate spoonbills were nearly hunted to extinction during the 1800s.
Their striking pink feathers were popular on women's hats, and hunters from all over the United States competed for spoonbill
plumes. In the early 1900s, roseate spoonbills began to re-colonize areas along the Gulf Coast and slowly increase in number.
Today, threats to roseate spoonbill populations come as a result of habitat loss.
Osprey
An osprey is a fish-eating hawk that has one of the widest distributions of any bird
of prey. If feeds entirely on fish, plunging from heights of up to 165 ft and entering
the water fee-first. Its wings are strong, its legs are heavily muscled, and its toes
have long, hooked talons and spiny soles- an adaptation that gives it a firm grip on
its slippery prey. These birds have been known to take prey that approaches their
own weight. They nest in the tops of high trees and hatch a single brood of two to
three chick each year. During the 20th centru, ospreys sufferend severely as a result
of the DDT pesticide. Their population has now recovered. In areas such as Florida, osprey are highly protected.
Any structure containing an osprey nest cannot be torn down or disturbed, including trees in the way of
construction.
Cormorant
Cormorants are equally at home in both fresh and salt water. They can be found
across a vst part of the world. Its plumage looks jet black. It fishes by pursuit
diving, and its feathers are partly waterproof. After feeding, it rests with its wings
spread apart to dry. They can often be seen floating in the surf with their long
necks curled outward in search of prey.
Wandering Albatross
This seabird has the largest recorded wingspan of any bird, at up to 11 ½ ft. There
are other species of albatross found in different parts of the world, but this species
stays along the southern oceans, where it feeds mainly on squid. It snatches its food
from the surface of the water, and is capable of remaining airborne for weeks at a
time. It frequently follows ships, soaring over the waves on its stiff, outstretched
wings. The wandering albatross takes up to 11 years to mature, and during that
time it becomes all white except for black markings on the tips and trailing edges
of its wings. They typically nest on remote islands, breeding in alternate years.