Sea Birds

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Sea Birds

• Class Aves

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Sea Birds

• Seabirds are those that spend a significant part
  of their lives at sea and feed on marine
  organisms. Seabirds nest on land.
• Most breed in large colonies, mate as lifelong
  partners, and take care of their young
• True seabirds have webbed feet for swimming

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Sea Birds
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Characteristics of all birds

• 1. Feathers feathers are unique to birds, and
  all birds have them. Like hair, feathers are
  composed mainly of the versatile protein keratin.
  Feathers are essential for flight, and they
  insulate a birds body against heat loss

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• Feathers are modified scales that serve 2 primary
  functions
• Provide lift for flight
• Conserve body heat

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• Soft fluffy down feathers cover the body of
  nestling birds and provide an insulating
  undercoat in adults.
• Contour feathers give adult birds their
  streamline shape and provide coloration and
  additional insulation.
• Flight feathers are specialized contour feathers
  on the wings and tail

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• The structure of a feather combines maximum
  strength with minimum weight
• Feathers develop from tiny pits in the skin
  called follicles

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• A shaft emerges from the follicle, and 2 vanes
  develop on opposite sides.
• At maturity, each vane has many branches called
  barbs.
• The barbs may have many projections called
  barbules, equipped with microscopic hooks. The
  hooks interlock and give the feather its sturdy
  and flexible shape.

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Characteristics of birds

• 2. Wings A birds forelimbs are modified into a
  pair of wings. Feathers cover most of the
  surface area of the wing

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Characteristics of birds

• 3. Lightweight, rigid skeleton The skeleton of
  a bird reflects the requirements of flight. Many
  of the bones are thin-walled and hollow, making
  them lighter than the bones of nonflying animals.
  Air sacs from the respiratory system penetrate
  some of the bones. Because many bones are fused,
  the skeleton is rigid and can resist forces
  produced by the strong flight muscles.

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• Birds have a smaller total number of bones than
  mammals or reptiles. This is because many of
  their bones have fused together making the
  skeleton more rigid. Birds also have more neck
  (cervical) vertebrae than many other animals
  most have 13 to 25 of these very flexible neck
  vertebrae (this helps them groom their feathers).
  Birds are the only vertebrate animals to have a
  fused collarbone (the furcula or wishbone) and a
  keeled breastbone.

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Characteristics of birds

• 4. Endothermic metabolism A birds rapid
  metabolism supplies the energy needed for flight.

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• Rapid breathing and digestion of large quantities
  of food support the high metabolic rate necessary
  to generate their high body heat.
• Birds, unlike reptiles, cannot go for long
  periods of time without eating.
• Aquatic birds have a thin layer of fat to provide
  insulation and stop heat loss.

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Digestive system

• The high amount of energy needed to fly and
  regulate body heat is obtained by a quick and
  efficient digestive system.

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Digestive System

• Because birds do not have teeth, they are not
  able to chew their food.
• Food passes from the mouth to the esophagus.
• An enlargement in the esophagus called the crop
  stores and moistens the food

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Digestive System

• Food then passes to the 2 part stomach.
• In the first chamber, the proventriculus, acid,
  and digestive enzymes begin to break down the
  food.

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Digestive System

• The food then passes down to the gizzard, the
  muscular portion of the stomach which kneads and
  crushes the food.
• The gizzard often contains small stones that the
  bird has swallowed to aid in the grinding process.

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Digestive System

• From the stomach, food passes into the small
  intestine, where the food is broken down more by
  enzymes and bile

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Excretory System

• The avian excretory system is efficient and
  lightweight.
• Unlike other vertebrates, most birds do not store
  liquid waste in a urinary bladder.
• 2 kidneys filter nitrogenous waste called uric
  acid from the blood

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• Concentrated uric acid travels through ducts
  called ureters to the cloaca, where it mixes with
  undigested matter from the intestines and is then
  eliminated

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Characteristics of Birds

• 5. Unique respiratory system A rapid metabolism
  requires an abundant supply of oxygen, and birds
  have the most efficient respiratory system of any
  terrestrial vertebrates. The lungs are connected
  to several sets of air sacs, an arrangement that
  ensures oxygen rich air is always in the lungs.

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Characteristics of Birds

• 6. Beak No modern bird has teeth, but the jaws
  are covered by a tough, horny sheath called a beak

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Characteristics of Birds

• 7. Oviparity All birds lay amniotic eggs
  encased in a hard, calcium-containing shell. In
  most species, the eggs are incubated in a nest by
  one or both parents

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Nervous System

• Relative to their body size, birds have large
  brains.
• The most highly developed areas of the birds
  brain are those that control flight-related
  functions, such as the cerebellum, which
  coordinates movement

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Nervous System

• The cerebrum is also large. It controls complex
  behavior patterns, such as navigation, mating,
  nest building, and caring for the young.

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Nervous System and Sense Organs

• The large optic lobes receive and interpret
  visual stimuli
• Keen vision is necessary for taking off, landing,
  spotting landmarks, hunting, and feeding.
• Most birds have good color vision that aids them
  in finding food

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• In most species, the eyes are large and are
  located near the sides of the head giving the
  birds a wide field of vision.
• Birds that have eyes located near the front of
  the head have better binocular vision, meaning
  they can perceive depth in the area where the
  visual fields of the 2 eyes overlap

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• Hearing is important to nocturnal species, which
  rely on sounds to help them locate their prey.
• The sense of smell is also well developed in many
  birds

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Gulls

• Gulls and their relatives make up the largest
  variety of seabirds.
• They are very successful in the company of humans
  and congregate near piers, garbage dumps, or
  anywhere else we throw garbage

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Local Shorebirds

• Herring Gulls Larus argentatus are large,
  raucous, and sometimes aggressive. They grow to
  20", with a wingspan of up to 55". These birds
  quickly learn to accept handouts, and will attack
  small children on the beach to steal food from
  them. Discourage this behavior by never feeding
  them. Immature specimens are as large as adults,
  but dirty brown.

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Local Shorebirds

• Laughing Gulls Larus atricilla are smaller,
  tern-like , with a black head and a laughing
  call. This is a common summer gull along the
  Atlantic and Gulf coasts, but its numbers have
  dropped in recent years because much of its
  coastal marsh habitat has been destroyed, and
  because Herring Gulls prey on its eggs and young.
  Laughing Gulls are very agile flyers and easily
  catch bits of food tossed into the air.

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Terns

• Terns are graceful fliers that hover over their
  prey before plunging for it.
• Their slender beaks are specialized to catch
  small fish, which they swallow whole

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Local Shorebirds

• Terns are smaller and more graceful in flight
  than gulls. The Common Tern Sterna hirundo grows
  to 14", wingspan 31". Their forked tails makes it
  easy to differentiate terns from Laughing Gulls,
  which also have black heads.
• Terns are found in the same habitats as gulls,
  that is to say, just about anywhere near water.
  Their call is a common sound along waterfronts
  everywhere.

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Local Shorebirds

• Black Skimmers are gull-like birds that catch
  small fishes by slicing their knife-like lower
  jaw through the surface of the water. The lower
  jaw is longer than the upper.They are usually
  seen in protected backwaters and bays

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Local Shorebirds

• The Great Egret feeds in shallow water or drier
  habitats, spearing fish, frogs or insects with
  its long, sharp bill. It will often wait
  motionless for prey, or slowly stalk its victim.
  It is a common species, usually easily seen.
• The Great Egret is partially migratory with
  northern hemisphere birds moving south from areas
  with cold winters. It breeds in colonies in trees
  close to large lakes with reed beds or other
  extensive wetlands. It builds a bulky stick nest

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Cormorants

• Cormorants are black, long-necked seabirds that
  dive and pursue their prey.
• They can be easily identified by their low
  flights over water and the fact that they float
  low in the water, with only the neck above the
  surface

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Local Shorebirds

• Phalacrocorax auritus
• This large ( 27", wingspan 50" ) seabird is more
  likely to be seen around back waters than in the
  open ocean. Cormorants seems rather poorly
  adapted to its lifestyle - they barely float, and
  their feathers are not waterproof like other
  waterfowl. As a result, they can often be seen
  standing on rocks and pilings or in trees in just
  this pose, sunning themselves to warm up and dry
  out after diving for fish. Despite this apparent
  disadvantage, they are quite successful, and even
  manage to over-winter in the area. Cormorants are
  amazing swimmers and divers, able to catch fish
  underwater in their own environment.

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Local Shorebirds

• The Spotted Sandpiper Actitis macularia is the
  most common member of a large family of
  long-legged shore birds.
• They are commonly seen teetering about on beaches
  and salt marshes. The breast is spotted only
  during the breeding season in winter it is plain
  white.
• Plovers are similar.

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Local Shorebirds

• Ospreys, or "Fish Eagles", Pandion haliaetus, are
  fairly common along shorelines, marshes, and
  larger inland waterways. They dive for fish,
  catching them with their talons - which is quite
  a sight to see. At the last moment in its
  headlong plunge, the bird pivots to strike the
  water feet-first.
• At 22", wingspan 54", Ospreys are smaller than
  eagles, but larger than hawks, and form their own
  family. Once threatened by DDT, which thins the
  shells of their eggs and makes then susceptible
  to breakage, Ospreys have made a great comeback,
  and may be seen around almost any salt marsh.
  They nest in trees, or on special platforms that
  are erected for them.

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Pelicans

• Pelicans have a unique pouch below their large
  beaks.
• Some species feed by plunging into the water and
  catching fish in the pouch

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Visitors

• Brown Pelicans Pelecanus occidentalis are
  southern birds that are occasionally found as far
  north as Cape May, rarely up to Nova Scotia.
  However, with the warmer temperatures of late,
  they seem to be expanding their normal range
  northward.
• These enormous ( 41", wingspan 6½') sea birds fly
  low over the water in lines, like geese, plunging
  down head-first to catch fish.

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Tubenoses

• Tubenoses comprise a large group of seabirds with
  distinctive tube-like nostrils and heavy beaks
  that are usually curved at the tip.
• They are very skillful fliers.
• Most catch fish at the sea surface, though some
  scavenge on dead birds or whales

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Visitors

• Storm Petrels are small ( 6.5", wingspan 16" )
  birds are truly sea-going, coming ashore only to
  reproduce. Petrels are apt to follow ships at
  sea, and can be quite common offshore, where they
  flit about just inches from the waves, never
  alighting. Floating droplets of oil, byproduct of
  natural decomposition, form a significant part of
  their diet.
• Wilson's Storm Petrel Oceanites oceanicus is
  considered to be the world's common seabird.
  Leach's Storm Petrel is similar, but has a forked
  tail instead of rounded.

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Visitors

• Shearwaters are gull- to tern- sized wanderers of
  the open sea that are sometimes found inshore.
  Generally dark plumage and rounded tails are
  identifying marks, although distinguishing
  between species is difficult. Up close, tubular
  nostrils become evident, a trait shared with
  related petrels. These are associated with the
  salt-secreting glands that allow the birds to
  drink seawater.
• Shearwaters fly low over the water, and also dive
  beneath the surface, "flying" underwater with
  partially folded wings. They feed on fish and
  squid.

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Visitors

• Northern Gannets Morus bassanus are the sole
  North Atlantic members of the Booby family. They
  resemble overgrown gulls, larger, with longer
  necks and wings. Distinguishing marks are a
  pointed tail, yellowish head, and dark gray or
  black outer wings.
• Boobies are fish divers like their cousins the
  Cormorants. Unlike Cormorants, though, Gannets
  make spectacular plunging dives from high
  altitude into the water after their prey.
• Gannets live and breed in the far north, but
  over-winter offshore in our area and south, when
  they can usually be seen swooping low over the
  waves singly or in pairs. They are powerful and
  agile fliers but clumsy on land, particularly in
  takeoffs and landings.

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New Jersey Endangered Birds

• One of New Jersey's greatest success stories is
  the Bald Eagle, a species that was brought "back
  from the brink" of extinction in N.J. This bird
  is believed to live over thirty years in the wild
  and longer in captivity. Also called the
  "American eagle". New Jersey's bald eagle
  population continued to grow during the 1995
  nesting season as 11 pairs nested. Nine of the
  pairs were successful at raising 20 young. All of
  the nests, with the exception of the Round Valley
  nest, are located within the Inner and Outer
  Coastal Plain of South Jersey. Bald eagles are
  very sensitive to disturbances, and will abandon
  their nest sites if people come too close to the
  nest. Most nests are on private land, and the
  landowners are the main protectors of nest sites.

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NJ Endangered Birds

• PIPING PLOVER- (Charadrius melodus) The piping
  plover is one of New Jersey's endangered beach
  nesters. The piping plover is named for its
  melodic mating call.  It is a small, pale-colored
  North American shorebird.   The bird's light
  sand-colored plumage blends in with sandy beaches
  and shorelines.
• There are three populations of piping plovers in
  the United States.  The most endangered is the
  Great Lakes breeding population, which
  encompasses only 32 breeding pairs in 2000.  The
  Northern Great Plains and Atlantic Coast
  populations are classified as threatened.  All
  piping plovers winter along the southeast and
  Gulf coasts and are classified as threatened in
  their wintering habitat. In recent decades,
  piping plover populations have drastically
  declined, especially in the Great Lakes Region. 
  Breeding habitat has been replaced by shoreline
  development and recreational uses causing plover
  numbers to plummet.  Similar threats face the
  species on its wintering grounds where loss of
  habitat threatens the ability of these birds to
  survive to the next breeding season.
• They grow to about 6-7 inches long and are
  grayish with white under parts and orange legs.
  They only live around sandy beaches. They nest in
  sand and lay 4, gray eggs that are lightly
  spotted with black. The mainly feed on insects
  and small aquatic species that are near the water
  line.

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NJ Endangered Birds

• PIED-BILLED GREBE-(Podilymbus podiceps) This bird
  is found on shallow inland waters. It seldom
  flies and likes to float high in the water. If it
  is alarmed, it slowly sinks instead of diving
  into the water. The Pied-Billed Grebe grows to
  about 12-15 inches long. They're a dull brown
  color with white stripes along its stomach.
  They're mainly found near ponds, marshes and
  quiet streams. They nest in a floating clump of
  marsh weeds and mud. The Pied-Billed Grebe eats
  insects, crustaceans and fish.

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NJ Endangered Birds

• NORTHERN HARRIER-(Circus cyaneus) This birds
  grows to about 17 inches long. Males are pale
  gray and females are are brown above and streaked
  with brown below. It lives in fields, marshes,
  and grasslands and it nests on platforms of
  sticks, reeds, and weed stems on ground or in
  shrubs. It eats mainly other small rodents like
  frogs, reptiles, insects, and other small birds.

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NJ Endangered Birds

• SAVANNAH SPARROW-(Passerculus sandwichensis) This
  bird grows to about 4-6 inches long. It's a
  finely streaked bird with brown coloring on the
  top and the bottom. It lives in prairies, fields,
  near water (salt and fresh), marshes, and grassy
  dunes. It nests in cups of grass, plant stems,
  and moss concealed in vegetation. It feeds on
  insects, seeds and spiders.

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NJ Endangered Birds

• LEAST TERN- (Sterna Antillarum Browni) This
  bird has long, narrow wings and a broad, forked
  tail identify the California least tern. Also
  have black-capped head and black-tipped, pale
  gray wings of the least tern contrasts with its
  white body. It bears a white blaze across its
  forehead, dark forewings, black-tipped yellow
  bill, and yellowish feet. It is less than 25 cm
  when fully grown and has 75 cm wingspan.

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NJ Endangered Birds

• ROSEATE TERN- (Sterna dougallii) This bird is
  36-43 cm long. It has a gray mantle across its
  back and wings, the head crown is black and the
  under parts are white with a bit of pink and a
  white tail. The tail is more forked and longer
  than the Common Tern. Their nest is a depression
  in the ground sometimes lined with a bit of dry
  grass or other plants.

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NJ Endangered Birds

• GREAT BLUE HERON- (Ardea herodias) An adult
  Great Blue heron grows to about 50-54 inches in
  length. They feed their young frogs and fish.
  They are mainly gray with a white head and 2
  black crown stripes. They live near marshes,
  lakes, rivers and shores. They nest about 100
  feet above the ground. Their eggs are pale
  blue-green and they lay about 3-7 eggs that take
  about 28 days to hatch. Adults mainly eat fish,
  frogs, snakes and small mammals.  

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