Feathered Friends Background Information

Feathered Friends Background Information
Revised 3/2011
LESSON PLAN VOCABULARY:
Abiotic Factor
Adaptation
Camouflage
Consumer
Ecosystem
Food Chain
Habitat
Hollow Bones
Niche
Predator
Binocular Vision
Contour Feather
Food Web
Limiting Factor
Prey
Biotic Factor
Down Feather
FWARPS
Monocular Vision
CA SCIENCE STANDARDS (updated by CDE 10/98):
• Students know producers and consumers (herbivores, carnivores, omnivores, and decomposers) are
related in food chains and food webs and may compete with each other for resources in an ecosystem.
(4.2.b)
• Students know ecosystems can be characterized by their living and nonliving components. (4.3.a)
• Students know that in any particular environment, some kinds of plants and animals survive well, some
survive less well, and some cannot survive at all. (4.3.b)
• Students know many plants depend on animals for pollination and seed dispersal, and animals depend
on plants for food and shelter. (4.3.c)
• Students know energy entering ecosystems as sunlight is transferred by producers in chemical energy
through photosynthesis and then from organism to organism through food webs. (6.5.b)
• Students know matter is transferred over time from one organism to others in the food web and between
organisms and the physical environment. (6.5.b)
• Students know populations of organisms can be categorized by the functions they serve in the
ecosystem. (6.5.c)
• Students know different kinds of organisms may play similar ecological roles in similar biomes. (6.5.d)
• Students know the number and types of organisms an ecosystem can support depends on the
resources available and on abiotic factors, such as quantities of light and water, range of temperatures,
and soil composition. (6.5.e)
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Feathered Friends
WHAT IS A BIRD?
A bird is a warm-blooded, egg-laying, vertebrate
consumer having its body covered with feathers
and its forelimbs modified into wings, which are
used by most birds for flight. Birds compose the
class Aves. There are an estimated 9,000 living
species.
larger than the body all make flight possible. The
size and the makeup of a bird’s wings will
determine the efficiency with which they can fly.
Owls, for instance, have very soft, light feathers
that allow for noiseless flight in order to catch
prey, even though the owl is proportionately large
and heavy.
HISTORY
Birds are believed to be extant members of a
group of dinosaurs called maniraptors (other
maniraptors include Velociraptor and Oviraptor).
They share with dinosaurs such characteristics as
a foot with three primary toes and one accessory
toe held high in back. Early avians include such
primitive birds as Arachaeopteryx, the roostersized Patagopteryx, and the ichthyornithiforms,
skillful flyers with toothed beaks. The fossil
remains of the Archaeopteryx, which date to the
Jurassic period, show reptilian tails, jaws with
teeth, and clawed wings, but feathers were well
developed. Pterosaurs, another group of flying
reptiles, did not share the common characteristics
of birds and dinosaurs and are not considered
birds. Whether the capacity for flight arose in treeliving dinosaurs that glided from branch to branch
(the “trees-down” hypothesis) or in fast-running
terrestrial dinosaurs (the “ground-up” hypothesis)
continues to be debated. Indeed, the inclusion of
birds in the dinosaur family tree, although
accepted by most paleontologists, is debated by
some, and the identification (2000) of the oldest
known feathers on 220-million-year-old, fourlegged reptile fossil, Longisquama insignis, raised
questions concerning the theory.
Feathers
Feathers are one of nature's finest achievements.
They can be extremely strong for flight but must
be extremely light and very flexible. If feathers
were too heavy, a bird would never become
airborne. There are several types of feathers:
bristles, contour feathers, down, flight feathers,
semiplumes, and filoplumes.
Bristles are those ornamental feathers with a shaft
that have interlocking barbs only as the base.
Contour feathers are those that cover the body
of the bird and give the basic color and shape to
the bird. Down feathers are the fluffy feathers
without shafts and form the downy plumage of
precocious chicks, those that are born with
feathers and are able to move about soon after
hatching. Examples are the fluffy poultry or duck
chicks. (Baby birds born with bare skin usually
develop contour feathers first, not down.) Down
acts as insulation, keeping birds warm, just as the
down feathers used in a down jacket keep you
warm. Flight feathers are the strong wing and tail
feathers that birds use to fly. Semiplumes are
similar to down but have a weak shaft, while
filoplumes are ornamental feathers that have
barbs only at the tips.
BODY CHARACTERISTICS
How do you know if an animal is a bird? Birds are
easily identifiable by characteristics on their
exterior and have some very special
characteristics that we can’t see!
Wings
Wings come in mandy shapes and sizes.
Sometimes you can identify what kind of bird you
are looking at just by the wingspan. The
American bald eagle, for instance, can have a
wingspan that can reach eleven feet in length or
more. A bird’s ability to fly is a remarkable
evolutionary accomplishment. Powerful but light
bones and cartilage, tightly patterned feathers,
powerful muscles, and wings proportionately
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Gizzard
A gizzard is a powerful, muscular organ, which is
capable of grinding up hard and even sharp
objects found in foods. Birds are very efficient in
their food consumption, as they eat every part of
what they take in their mouth. Most things are
swallowed whole. Those parts which are not
easily digested, such as shells, or seeds, are
ground up by the gizzard before being passed into
the digestive system. Owls have a particularly
complex way of taking what it needs from its prey
and then expectorating a waxy pellet, usually filled
with undesirable bones and hair.
Looking at a bird you can see that the various
types of feathers are arranged over the bird's
body in an extremely ordered fashion. For flying,
the feathers on the front leading edge of the wing
are very streamlined. The outer trailing edge of
the wing may be fringed to break up the flow of
the air, as well as to silence the flight. Feathers
overlap each other, usually covering most of a
bird's skin. This overlapping curved and
streamlined shape is perfect for flight.
Beaks
Beaks vary among different species of birds,
usually depending upon what they eat. For
instance: Hummingbirds have long hollow beaks
that they use to probe flowers for nectar; curlews,
godwits kiwis, and snipes have very long beaks
that they use to probe for worms, crustaceans,
and other small creatures in mud and water;
cardinals, sparrows, grosbeaks and other finchlike
birds have very short conical beaks that are very
strong and can break open tough seeds;
spoonbills and pelicans have long flattened or
pouchlike beaks that they use to scoop up fish ad
other aquatic creatures; flamingos and some
ducks have bills that act like strainers to filter tiny
plants and animals from the water; nighthawks,
whip-poor-wills, swifts and swallows have large
gaping mouths that act like nets to trap insects.
These birds catch insects on the wings; warblers
have small sharp, pointed beaks for picking
insects from leaves, longs, and twigs; toucans
have very long thick beaks for reaching out and
plucking fruit from trees.
Eyes
The eyes of most birds are on the side of their
heads. This placement allows them to be able to
see the things on each side at the same time as
well as in front of them. This type of vision is
called monocular vision. Birds with eyes placed
like this get a wide area of vision to be able to see
danger as quickly as
possible. For instance,
Rock Doves (pigeons)
can see 300 degrees
without turning their
head. Some birds, like
Woodcocks, have their
eyes placed far back on
the sides of their heads,
allowing them even to
see danger behind them. However, with
monocular vision, birds have a harder time
judging distances and have worse depth
perception.
The vision that occurs when the field of vision
from each eye overlaps is called binocular
vision. Birds, such as raptors, have their eyes
placed far to the front giving them binocular vision
as people have. These birds may have a 180
degree field of overall
vision with much of that
binocular. They have
much sharper vision to
the front than than their
monocular cousins. For
instance, the Rock Doves
may only have 30
degrees of binocular
vision.
Owls, with wonderful binocular vision, make up for
the lower field of vision by an amazing ability to
turn their heads to face backwards. Also most
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birds' eyes do not move in their sockets as our
eyes do. Reflex movements of their necks usually
replace the eye movements.
Shape
Type
Grasping
Bones
Scratching
Swimming
The fact that a pelican approximately 5 feet long
weighing nearly 20 pounds has a skeleton
weighing only 23 ounces indicates how perfectly a
birds skeleton is adapted to its capacity for flight.
The reason the skeleton is so lightweight is that
many bones in a bird's skeleton are hollow. The
hollow bones are honeycombed with air spaces
and strengthened by crisscrossing struts. The
number of hollow bones varies from species to
species, though large gliding and soaring birds
tend to have the most. In general, the more
efficient fliers seem to have more bones that are
hollow.
A bird's streamlining for flight is perhaps best
exemplified in the evolution of the skull, which is
composed mainly of thin, hollow bones. A bird's
skull is extremely light in proportion to the rest of
its body due to elimination of a heavy jaw, jaw
muscles, and teeth; the job of chewing has largely
replaced by the gizzard. The skull usually
represents less than 1 percent of a bird's total
body weight.
Knees?
Yes, birds have knees (they're often under the
feathers and not easily visible), and they bend the
same way our knees bend. The part of a bird's
legs that bends backwards when it walks is the
ankle.
Feet
Birds have many different shapes and sizes to
their feet. Like the shape of the bill, the anatomy
of birds' feet tells us much about the ecology of
different species of birds. Below are several
examples of birds’ feet and what each one can tell
us about the group of birds who possess them.
Perching
Running
Climbing
Adaptation
Raptors like
Osprey use their
large curved
claws to snatch
fish from the
water.
Pheasants and
other birds that
scratch the soil
for food have
nail-like toes.
Ducks and other
webbed lined
swimming birds
use their feet
like paddles.
Robins have a
long back toe,
which lets them
grab a perch
tightly.
Many fastrunning birds
have three toes
rather than four.
A woodpecker's
hind toes enable
it to climb
without falling
backward.
Heart Rate and Breathing
In order to fly, birds need a lot of oxygen, which
they get by breathing air, using lungs. They also
need a strong circulatory system, including a
powerful heart in order to circulate the oxygen. A
bird's heart beats much faster than our heart
does. A hummingbird's heart beats about 1,000
times each minute; a human's heart beats about
60-90 times each minute.
Birds breathe using a unique system in which air
follows a one-way route through the respiratory
system. This system is unlike our lungs, in which
the air backtracks where it came from. Their
system of respiration (breathing) is very efficient much more efficient than our system.
Birds have two relatively small lungs (where gas
exchange occurs), but the lungs are augmented
by bellows-like air sacs (where no gas exchange
occurs). These air sacs keep the lungs
perpetually inflated (even when the bird is
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exhaling). Our lungs alternately fill and empty out.
The bird's respiratory system takes up 20% of a
bird’s volume (our respiratory system takes up
only 5% of our volume).
In the bird's respiratory system, air first flows
through air sacs (located even inside their hollow
bones) that direct fresh, oxygenated air into the
tube-like lungs (parabronchi, where gas exchange
occurs) both when the bird inhales and when it
exhales.
This system increases birds' respiratory efficiency
and gives them enough oxygen for flight.
DIET
Modern-day birds do not have any teeth (ancient
birds did have teeth). Birds have a tongue, but
unlike our tongue, a bird's tongue has a bone in it.
Each species of bird has eating habits, which
have evolved over millions of years, and although
its diet at any one time may reflect the availability
of food, in general there is an amazing variety of
diets, ranging the full gamut from herbivorous,
through omnivorous, to carnivorous.
• Vegetarian diets include: grasses, seaweeds,
herbaceous plants, fruit, nuts, grains and
seeds, pollen and nectar.
• Carnivorous diets include: insects, worms,
spiders, crustaceans and other invertebrates,
amphibians, fish, reptiles, mammals, other
birds, and carrion.
Between these two extremes, there are many
species of omnivores, opportunistic birds which
will take pretty much anything that's going! Such
a variety of diets has produced different foraging
strategies.
Based on their diets, a bird can find itself on any
level of a food chain, from the bottom to the top,
and as a predator or prey within a food web.
NESTS AND EGGS
Birds bear their young in hard-shelled eggs, which
hatch after some time. Some birds, like chickens,
lay eggs each day, others (like the maleo) may go
for years between laying eggs. The incubation
period of bird eggs varies from species to species.
There's also some variability due to the
temperature.
Birds build nests for breeding in trees, on cliffs,
or on the ground. Most birds are taken care of by
at least one parent until they are able to fly and
get their own food. Some birds, like cuckoos and
some cowbirds, lay their eggs in other bird's
nests. The non-related adult bird takes care of the
cuckoo's egg unwittingly. Some cuckoos even kill
the other eggs in the nest to insure that their egg
gets enough food.
NICHE
Birds play an important role in their ecosystem.
Seed dispersal by birds, especially fruit seeds, is
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invaluable to many plants. Frugivorous birds,
fruit-eating, are more common in tropical areas
and allow the progeny of a plant to move away
from the parent plant in space and time.
Birds are very important pollinators of wildflowers
throughout the world. In the continental United
States, hummingbirds are key in wildflower
pollination. Hummingbirds have very good eyes
and are extremely attracted to red. They thrust
their long slender bills deep into the flowers for
nectar, withdrawing faces dusted in pollen.
Can a bird pollinate and
disperse seeds? The white wing
dove can! The doves
synchronize their migration into
the Sonoran Desert with the
reproductive cycle of saguaro
cactus. White-winged doves are
important to saguaros as
pollinators but they are also the
main seed predators of saguaros. This is an
interesting ecological balance.
Predator birds help keep things in balance. Any
kind of predatory animal is going to help keep
things that have a tendency to overpopulate like
insects, rodents or snakes in check. If you take a
predator out of the equation, the organisms they
hunt are going to overpopulate and there won't be
enough food for them.
Many birds are useful as scavengers. They clean
up nature’s “garbage” to help keep the earth a
cleaner place.
Game birds are hunted for food and sport; they
include grouse, pheasant, quail, duck, and plover.
The chief domestic birds are the chicken, duck,
goose, turkey, and guinea fowl. Parrots and many
members of the finch family are kept as pets.
MIGRATION
Many species of land migratory birds migrate very
long distances, the most common and best known
pattern being for birds to breed in the temperate
or Arctic northern hemisphere and spend the nonbreeding season in warmer regions, often in the
tropics or the temperate zones of the southern
hemisphere.
The primary advantage of migration is energetic.
In the long days of the northern summer, breeding
birds have greater opportunities to feed their
newly-hatched young on often abundant food
supplies. As the days shorten in autumn and food
supplies become scarce, the birds can return to
warmer regions where the available food supply
varies little with the season, and without young to
feed their requirements are less.
ADAPTATIONS
Birds have been around since the dinosaurs.
They are able to survive in all types of
environments. This is due to some fantastic
adaptations that are useful in getting food and
hiding from predators. Some adaptations that
birds have are solely for food purposes. The
beak, for example, is shaped perfectly for the type
of food that particular bird ingests.
The hummingbird has a
beak like a straw, sticking
it into flowers to sip the
nectar.
The spoonbill uses its
bill like a shovel,
moving it back and
forth through shallow
waters to shovel small
fishes and crustaceans
from the mud and
water.
The eagle’s short strong
beak with hooked upper
jaw is used for tearing
flesh.
It’s not only the beak that is different from bird to
bird. Their feet are also unique. Most birds have
four toes on each foot, and all birds have a claw
at the tip of each toe. However, the arrangement
and size of the toes and the size and shape of the
claws vary according to the birds' ways of life.
Birds of prey have long, sharp,
curved claws for catching,
grasping, and ripping apart
their prey.
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Some birds that are good climbers, including
parrots and woodpeckers, have two toes pointing
forward and two toes
pointing backward. The hind
toes provide an extra grip for
the birds as they climb.
Another physical adaptation is camouflage, the
use of its appearance to protect itself against
predators. From blending in with the environment
to warning off predators, a bird’s camouflage is
often its only defense.
A good example of camouflage is the Ptarmigan.
The Ptarmigan is a type of grouse living in the far
north, in Alaska, northern Canada, Greenland,
Scandinavia and Siberia. In summer, its feathers
are brown and mottled like the tundra it lives in.
Like many other bird species, it uses brownish
camouflage to hide from predators.
But the Ptarmigan spends its
winters farther north than any
other bird. Snows soon blanket
its home – brown feathers
would be too obvious against
the white landscape. So the
Ptarmigan molts into brilliant
white feathers in winter. This
makes the bird almost invisible
in its snowy home. Fluffy white
feathers even cover the
Ptarmigan’s feet – keeping
them warm and turning their feet into wide
snowshoes.
The color or pattern of a
bird’s feathers is not
necessarily used for
camouflage. Male
Cardinals do not use
camouflage. The bright
red color is meant to be
an aggressive signal to
stay away. Yet their
female counterparts have
muted colors and they can hide in trees, bushes
and underbrush with like colors. Many male birds
are brightly colored to attract a mate, not ward off
others.
HABITATS
Birds live in a variety of different habitats, from
oceans to forests, wetlands to grasslands. As
long as they have access to their FWARPS and
can live out their lives safely, a bird is in a good
situation.
Key biotic factors necessary for a bird’s habitat
are: food (seeds, insects, whatever that specific
bird eats), plants, soil, and even predators to keep
the population at a healthy level. Necessary
abiotic factors include: water, wind, oxygen,
periods of light and darkness.
Within their habitats, birds use nests to protect
eggs and nestlings from predators and adverse
weather. To minimize predation, birds may use or
build nests that are inaccessible, hidden, or
camouflaged. Nests may also help keep eggs and
nestlings warm.
SURVIVAL
Many limiting factors determine the survival of o
bird, from habitat loss to natural predators to
overpopulation. Although there are natural
threats to the survival of many birds, conservative
estimates are that more than a billion birds are
killed annually in the USA as a result of human
activities. Licensed hunting and pest control
account for a small portion of these deaths; the
vast majority of deaths result from a variety of
other human activities.
The Ptarmigan is also unusual in having three
different camouflages: Summer-Brown, WinterWhite, and in spring, the Ptarmigan becomes a
patchy half-brown, half-white. This springtime coat
helps hide the Ptarmigan when the tundra is
patchy with melting snow.
Pet cats that are allowed to roam free account for
some 4 MILLION bird deaths EACH DAY in North
America, or over 1
BILLION songbirds each
year. This figure does not
include the losses
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resulting from feral or wild populations of cats.
Cats are efficient predators, and even capture
some of the most secretive birds, such as Yellow
Rails.
SOLUTION: By simply controlling the activities of
our favorite pet cats, we can make a significant
contribution toward conserving populations of
songbirds.
More than 57 million birds
are killed each year from
collisions with vehicles.
This averages out to
about 15 bird deaths per
mile per year.
SOLUTION: Most of these are probably not
avoidable, but many can be prevented by careful
driving, especially in local areas where birds are
known to cross roads frequently.
Nearly a million songbirds are killed each year by
collisions with lighted tall buildings. Once again,
birds that migrate at night suffer the most.
Southern exposures
present the greatest risk
to birds coming north
during the spring
migration. Northern faces
of buildings are the
greatest risk during fall
migrations.
SOLUTION: Darken high rise buildings during the
spring and fall migratory period.
The continued loss of
critical breeding and
migratory stopover habitat
to human development
poses a devastating threat
to wild bird populations.
The construction site pictured has been totally
wiped clean of the mature secondary forest that
once existed here. Without suitable breeding
habitat, birds cannot maintain their populations.
Without key migratory stopovers, birds cannot
even reach their breeding grounds. As human
populations increase, this problem will likely
worsen.
SOLUTION: Thoughtful land use planning can go
a long way toward identifying and conserving
those habitats that are critical to birds and other
forms of wildlife. Development that does occur
can be planned to preserve some habitat areas.
IDENTIFYING BIRDS
Whether out on a hike or looking through your
bedroom window, you can narrow down the type
of birds you see by knowing a few bird basics.
Relative Size
Once you’ve determined the approximate size of
the bird being observed you can begin to narrow
the possibilities. Is it sparrow sized, robin sized,
pigeon sized, or hawk sized? Knowing this can
definitely tell you what the bird is not.
Behavior
Does the bird hop or run? What type of flight
pattern does it display? Does it beat its wings
rapidly or slowly? Does it have any distinct habits
(i.e. bobbing up and down)? Does it hug close tot
he trunk of a tree; if so is it’s head pointing up the
tree or down the tree? Searching for distinctive
behavior is helpful in bird identification.
Songs and Calls
With a little practice you can begin identifying
birds with your ears long before your eyes see
them. Birds have distinct songs and calls, which
positively identify them. Songs and calls for each
species are provided in every good field guide.
Sounds are transcribed into words.
Is it a song or a call?
• Song: These are generally vocalizations that
specifically serve to attract a mate and to
defend a territory. Songs are usually (but not
always) more elaborate than calls. They are
usually a seasonal performance of spring.
• Calls: That which is not a song. Calls may
communicate the presence of food or
predators, or it may help members of a family
or flock stay in contact. Young birds may call
to be fed by parents. Some species of birds
have a large and variable repertoire of calls,
while other birds may not. The vast majority
of species have calls that can be heard
throughout the year, in contrast tot he
seasonal occurrence of most songs.
In order to identify birds by their vocalization, you
must first of all listen very carefully. The more you
listen, the easier it gets.
FACTS
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•
•
•
•
•
The peregrine falcon is one of the fastest
birds, and has been clocked at 90 miles per
hour in a dive (and some people say that they
can dive at over 200 mph).
The fastest running bird is the ostrich, but it
cannot fly. The ostrich is also the fastest twolegged runner of all the animals on Earth. The
ostrich is the largest bird.
Some amazing hunters, like eagles, have
eyesight that is five to six times sharper than a
person's. They can spot small prey from a
mile away.
The only backwards and sideways flyer is the
hummingbird.
Feathers are actually modified scales!
COMMON BIRDS OF SOUTHERN CAL
Red-tailed Hawk
Vocalization: The Red-tailed Hawk has hoarse
and rasping 2- to 3-econd scream that is most
commonly heard while soaring. They are loudest
when defending their nests. When parents leave
the nest, the young utter a loud wailing "klee-uk,"
repeated several times - this is a food cry.
Tail: The Red-tailed Hawk has a broad, rounded
tail that shows a rich, russet red.
Eyes: The eyesight of a hawk is eight times as
powerful as a human's.
Behavior: The Red-tailed Hawk is the most
widespread and familiar member of the American
Buteos (large soaring hawks). They nest in the
month of March in tall tress. Like all other Buteos,
it does not fly fast but soars at high altitudes using
its keen eyesight to spot the slightest movement
in the grass below. It is an aggressive bird and
vigorously defends its territory, especially during
the winter months when hunting is difficult.
Habitat: The Red-tailed Hawk is usually found in
grasslands or marsh- shrub habitats, but is very
adaptable bird, being equally at home in deserts
and forests, and at varying heights above sea
level.
Food and Hunting: The Red-tailed Hawk is a
most opportunistic hunter. Its diet is varied, but
there is conclusive evidence now that 85 to 90 %
is composed of small rodents, with rabbits,
snakes and lizards included. Where there are
large numbers of pheasant, these become the
food of choice in spring and summer. Like all
hawks, its talons are its main weapons.
Breeding: Mating and nest building begin in early
spring, usually in March and continue through
May. This is accompanied by spectacular aerial
displays by both males and females. Circling and
soaring to great heights, they fold their wings and
plummet to treetop level, repeating this display as
much as five or six times.
Nests are located from 35 to 75 feet high in the
forks of large trees. The nest is large, flat, shallow
and made of sticks and twigs about 1/2 inch in
diameter. Both males and females assist in nest
construction. Nest sites may be used from year to
year, since there is strong evidence that hawks
mate for life. If the old nest is wind damaged,
layers of new nesting material are added each
year.
The female usually lays 2 dull-white to bluishwhite eggs that are marked with a variety of
irregular reddish spots and splotches. Incubation
takes 28-32 days and is maintained almost
entirely by the female. During this period the male
hunts for both of them, bringing her food to the
nest.
When hatched, the young are covered with white
down. They grow slowly and require much food,
which keeps both parents busy. They remain in
the nest for up to 48 days. During the last 10 days
or so the young, which now appear as large as
the parent birds, practice flapping their wings and
balancing in the wind on the edge of the nest,
preparing for the days when they will launch
themselves into the air.
The young fledge at about 45 days. Red-tails
typically do not begin breeding until their third
year.
Conservation: In California, state and federal
laws protect all raptors. Because of their
inexperience hunting, juvenile birds may be seen
eating road-killed animals. They may even kill
chickens, and despite this rare occurrence, the
Red-tail is known throughout the country as a
"chicken hawk." As a consequence, dead hawks
hanging from fences and lying under trees and
power poles are mute evidence that shooters, not
understanding the economic or esthetic
importance of raptors, or perhaps unaware of
protective laws, still kill them indiscriminately. In
the rare case of an individual raptor or hawk that
engages in active predation on domestic birds or
animals, such a bird may be judiciously removed
in accordance with current regulations.
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Turkey Vulture
Range: All four of the southwestern deserts. The
barn owl occurs in great numbers in Southern
California.
Barn Owl
Range: Throughout all the deserts of the
Southwest, as well as most of North America.
Habitat: Dry, open country, ranch lands and
along roadsides where carrion is common.
Description: The Turkey Vulture is one of North
America's largest birds of prey. It reaches a length
of 32 inches with a wingspan of 6 feet. Its overall
color is brown-black with a featherless, red head,
white bill and yellow feet among mature adults.
Immature birds have a darker face. Although
usually silent, the bird will occasionally emit a soft
hiss or groan.
In flight, the Turkey Vulture rocks from side to
side, rarely flapping its wings which are held at a
V-angle called a dihedral. Silver-gray flight
feathers look lighter than the black lining feathers
of the underwing. Its long tail extends beyond its
legs and feet in flight.
Habits: Vultures are best known for their practice
of feeding on dead animal carcasses, but will
occasionally attack young and helpless animals
as well. They obtain much of their water from the
moisture in carrion, and their powerful kidneys
enable them to excrete less water when expelling
waste products.
Turkey vultures, like other carrion birds, are
protected from disease associated with decaying
animals by a very sophisticated immune system.
Their unfeathered "bald" head is easy to keep
clean and is characteristic of vultures and condors
throughout the world.
Mating occurs in all deserts except the Mojave.
One to three blotched eggs are laid in cliff
hollows, logs or among rocks on the ground; no
nest is built. Both parents participate in incubation
of the eggs for up to a month. Newly hatched
young are fed with regurgitated food for the first
few days and fly from the nest within 10 weeks.
Unlike most birds, vultures have a keen sense of
smell. The Turkey Vulture's olfactory sense is
estimated to be 3 times that of the smaller Black
Vulture, which is also found in the North American
Deserts. The California Condor, now almost
extinct, is the third member of the Cathartidae
Family, referred to as the American Vultures.
Vultures are sometimes mistakenly called
buzzards, the British name for buteos -- hawks of
the Buteo genus.
Habitat: Hunts in areas rich in rodents, along
desert washes and canyons, where trees for
perching are available.
Description: The barn owl can readily be
distinguished from other owls by its unique shape,
color and voice. This distinctive, medium-sized
owl grows 15 to 20 inches in height. It has long,
feathered legs and makes a loud, rasping hiss,
rather than the hoot associated with other owls.
The Barn Owl is primarily white with buff, yellow
and tawny shadings. It is delicately freckled with
dark specks and the blending of colors in daylight
has led some to call it, the "golden owl." Other
common names are for it are the "White Owl" and
"Monkey-faced Owl."The barn owl's face is
arresting. There are no ear tufts. The eyes and
beak are completely encircled by a heart-shaped
facial ruff of white, rimmed with tan while slightly
curved feathers radiate out from the small, dark
eyes.
The eyes of owls look forward in a fixed position
and cannot move to the side, as the human eye
can. Therefore, to see to the side or back, the owl
must turn its whole head. They see extremely well
at night. Their hearing must be extremely acute
also, for it is known that a barn owl can strike a
mouse in the dark.
Habits: Barn Owls are more nocturnal than other
owls. They wait until dark before starting out to
hunt, except when the demands of their young
may start them hunting at twilight. Normally,
before daylight, they retire to some shadowed or
enclosed area in an old building, a hollow tree or
a hole in a rocky cliff and remain there drowsily
inactive all day.
When hunting at night, the Barn Owl sweeps the
fields on silent wings catching its prey with its
long, slender claws. It prefers small mammals but
occasionally in winter when mice and gophers are
scarce, it will take small birds. The prey is tom
apart and swallowed -- bones, skull and all. The
indigestible parts are formed into pellets and
disgorged at the roosting area or about the nest.
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Life Cycle: Barn owls choose nesting sights
almost anywhere, in old buildings, hollow trees
and on or in the ground. No effort is made to build
or even line the nest. The female lays from 5 to 7
white, spotless eggs at intervals of 2 or 3 days.
Incubation starts after the first egg is laid. It takes
from 32 to 34 days for the first egg to hatch, so a
nest may contain 4 or 5 young of different size
and age. The young are called "owlets." They are
covered with snow-white down for 6 days. This is
gradually replaced by a buff-colored down, which
develops into a thick, woolly covering that is still in
evidence for about 50 days.
The little owlets are hungry all the time. Both
parents are busy night after night ransacking the
adjoining areas to catch an unbelievable number
of small ground creatures to feed their ravenous
babies.
Adult plumage is acquired in about 7-1/2 weeks,
at which time, after much practicing about the
nest, the young venture out for their first lessons
in flying and hunting.
Habitat: Openings and edges of coniferous and
mixed woods; in winter, fields, roadsides, parks,
and suburban gardens.
Nesting: 3-6 pale bluish or greenish eggs, with
variegated blotches concentrated at the larger
end, in a deep, compact nest of rootlets, shreds of
bark, twigs, and mosses, lined with grasses and
hair, placed on or near the ground, protected by a
rock ledge, a mud bank, tufts of weeds, or a fallen
log.
Range: Breeds from Alaska east across Canada
to Newfoundland, south to mountains in Mexico
and Georgia. Winters south to Gulf Coast and
northern Mexico.
Discussion: This lively territorial bird is a ground
dweller and feeds on seeds and small fruits in the
open. It also moves through the lower branches of
trees and seeks shelter in the tangle of shrubs.
Until recently the many geographical forms of this
bird were considered separate species, but since
they interbreed wherever their ranges meet, they
are now considered one species.
Dark-eyed Junco
Acorn Woodpecker
Description: 5-6 1/4" (13-16 cm). This species
shows much geographic variation in color.
Typically, male of western population ("Oregon
Junco") has black hood, chestnut mantle, white
underparts with buff sides. Eastern male ("Slatecolored Junco") is dark slate-gray on head, upper
breast, flanks, and upperparts, with white lower
breast and belly. Both forms have pink bill and
dark gray tail with white outer tail feathers
conspicuous in flight. The pine forests of the Black
Hills in western South Dakota and eastern
Montana have an isolated population ("Whitewinged Junco") similar to the eastern form but
with 2 white wing bars and extensive white outer
tail feathers. Birds of the Southwest ("Grayheaded Juncos") are gray overall, with a reddishbrown back. Female "Oregon Junco" has gray
hood; females of all forms less colorful.
Voice: Ringing metallic trill on the same pitch.
Members of a flock may spread out widely,
keeping in contact by constantly calling tsick or
tchet. Also a soft buzzy trill in flight.
Description: 8-9 1/2" (20-24 cm). Male has
yellowish-white forecrown; red crown; light eyes;
black nape, back, wings, and tail. Chin black;
throat and sides of head yellowish white; breast
and flanks whitish with heavy dark streaking;
belly, wing patches, and rump white. Female has
black forecrown, otherwise identical to male.
Voice: A loud ja-cob, ja-cob or wake-up, wake-up.
Habitat: Open oak and pine-oak forests.
Nesting: 4 or 5 white eggs in a hole in a tree.
Nests in colonies, with all members of colony
sharing in excavating holes-mostly in dead oak
branches-feeding young, and possibly incubating.
Range: Resident from southern Oregon south
through California, and in Arizona, New Mexico,
and western Texas. Also in tropics.
Discussion: This well-named woodpecker
harvests acorns and, in agricultural or suburban
areas, almonds and walnuts as well. In autumn
the birds store their crop of nuts tightly in
individual holes so that no squirrel can pry them
out. The storage trees are usually mature or dead
pines or Douglas firs with thick, soft bark, but
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dead oak branches and fence posts are also
used. The holes made by a colony are used year
after year. Acorns seem to be emergency
provisions; on mild winter days these birds catch
flying insects.
American Crow
Description: 17-21" (43-53 cm). Stocky black bird
with stout bill and fan-shaped tail. Smaller
Northwestern Crow has hoarser voice; larger
Common Raven has wedge-shaped tail.
Voice: Familiar caw-caw or caa-caa.
Habitat: Deciduous growth along rivers and
streams; orchards and city parks. Also mixed and
coniferous woods, but avoids closed coniferous
forests and desert expanses.
Nesting: 4-6 dull green eggs, spotted with dark
brown, in a large mass of twigs and sticks lined
with feathers, grass, and rootlets, and placed in a
tree.
Range: Breeds from British Columbia, central
interior Canada, and Newfoundland south to
southern California, Gulf Coast, and Florida.
Winters north to southern Canada.
Discussion: Intelligent, wary, virtually
omnivorous, and with a high reproductive
capacity, the American Crow is undoubtedly much
more numerous than it was before the arrival of
settlers. An opportunist in its feeding, the
American Crow consumes a great variety of plant
and animal food: seeds, garbage, insects, mice.
Its nest plundering is decried, but in orchards and
fields it destroys many injurious insects such as
grasshoppers and cutworms. However, the
labeling of birds as either "harmful" or "useful" is
misleading and antiquated. Crows do destroy
many eggs and nestlings of woodland and
meadow birds, but they also weed out the weak
and feeble, and they alert the animals in a
neighborhood when danger approaches.
Western Scrub Jay
Description: 11-13" (28-33 cm). Robin-sized, but
large strong bill and long tail make it appear
larger. Head, wings, and tail blue (conspicuous
when it glides in a long, undulating flight); back
dull brown; underparts light gray. No crest; dusky
face mask. White throat offset by incomplete blue
necklace.
Voice: Call is loud, throaty jayy? or jree? In flight,
a long series of check-check-check notes.
Habitat: Scrub oak, woodlands, and chaparral,
but does not breed in low scrub because it needs
watch posts; also inhabits suburban gardens.
Nesting: 3-6 eggs, spotted on darker, greenish or
reddish base, in a twiggy nest well hidden in a
tree or dense shrub.
Range: Resident from Washington, Wyoming,
and Colorado south to Texas; also in Mexico.
Discussion: Like all jays, this species may be
secretive and silent around its nest or while
perching in a treetop in early morning but is
frequently noisy and conspicuous. Scrub jays
often eat the eggs or young of other birds, but in
summer they are mainly insectivorous. These
birds also eat acorns and have been described as
"uphill planters," counter-balancing the tendency
of acorns to bounce or roll downhill. The jays bury
many more acorns than they consume and help
regenerate oak forests that have been destroyed
by fire or drought.
Mallard Duck
Description: 18-27" (46-69 cm). Male has a
green head, white neck ring, chestnut breast, and
grayish body; inner feathers of wing (speculum)
are metallic purplish blue, bordered in front and
back with white. Female mottled brown with white
tail and purplish-blue speculum; mottled orange
and brown bill. Form in Southwest ("Mexican
Duck") similar to typical female Mallard but darker;
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speculum blue; bill of male yellow-green; bill of
female dusky orange; no white in tail.
Voice: Male utters soft, reedy notes; female, a
loud quack.
Habitat: From ponds, lakes, and marshes to
small river bends, bays, and even ditches and city
ponds.
Nesting: 8-10 light olive-green eggs in a downlined nest often placed some distance from water,
occasionally even in a tree.
Range: Breeds from Alaska and Quebec south to
southern California, Virginia, Texas, and northern
Mexico. Winters throughout United States and
south to Central America and West Indies. Also in
Eurasia.
Discussion: The Mallard is undoubtedly the most
abundant duck in the world. Nearly 10 million live
in North America, and millions more are found in
Eurasia. Since the Mallard is the ancestor of the
common white domestic duck, still more can be
added to the total. Mallards frequently interbreed
with domestic stock, producing a bewildering
variety of patterns and colors. They also hybridize
with wild species such as the closely related
American Black Duck and even occasionally with
Northern Pintails. Strong fliers, Mallards
sometimes reach remote oceanic islands where
isolated populations have evolved into new
species. Like the Mottled Duck, these isolated
populations often differ from the Mallard mainly in
that they lack the colorful plumage of the male.
Mallard courtship starts in the fall, and by
midwinter pairs have formed. Mated pairs migrate
northward together, heading for the female's
place of origin. The male stays with the female
until incubation is well underway, then leaves to
join a flock of other males to begin the annual
molt.
Description: 5-6" (13-15 cm). Sparrow-sized.
Blue-gray above, white underparts and face, black
crown. Usually seen creeping on tree trunks, head
downward.
Voice: A nasal yank-yank. Song a series of low
whistled notes.
Habitat: Deciduous and mixed forests.
Nesting: 5 or 6 white eggs, lightly speckled with
red-brown, in a cup of twigs and grass lined with
feathers and hair in a natural cavity, bird box, or
hole excavated by the birds.
Range: Largely resident from British Columbia,
Ontario, and Nova Scotia south to southern
California, Arizona, Gulf Coast, and central
Florida. Absent from most of Great Plains.
Discussion: The habit of creeping headfirst down
a tree trunk, then stopping and looking around
with head held out at a 90-degree angle, is
characteristic of nuthatches. The White-breasted
is an inquisitive, acrobatic bird, pausing
occasionally to hang and hammer at a crack.
Essentially nonmigratory, during the fall it stores
food for winter in crevices behind loose tree bark.
Pairs seem to remain together year-round, for the
species may be found in twos even in the dead of
winter. Although they often join mixed flocks of
chickadees, woodpeckers, and kinglets roaming
the winter woods, they tend to remain in their
territories. They are familiar visitors to bird
feeders.
Stellar’s Jay
White-breasted Nuthatch
Description: 12-13 1/2" (30-34 cm). The only
western jay with a crest. Front half of bird sooty
black, rear dark blue-gray, with tight black
crossbarring on secondaries and tail. Lightly
streaked eyebrow, chin, and forehead markings
vary considerably.
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Voice: A harsh shack-shack-shack-shack or
chook-chook-chook call reveals its presence. May
also mimic the screams of hawks.
Habitat: Coniferous forests: pine and oak woods
in southern part of range, small groves and stands
of mixed oak and redwood in northern California.
Nesting: 3-5 spotted greenish eggs in a neat
twiggy bowl lined with small roots and fibers, well
hidden in a shady conifer.
Range: Largely resident from coastal southern
Alaska east to Rocky Mountains and southward
into Central America.
Discussion: Somewhat more reticent than the
Gray Jay, Steller's nevertheless quickly becomes
accustomed to campsites and human providers. It
is often seen sitting quietly in treetops, surveying
the surroundings. Near its nest site, it is silent and
shy.
Western Tanager
Description: 6-7 1/2" (15-19 cm). Adult male has
brilliant red head, bright yellow body, with black
back, wings, and tail. 2 wing bars; smaller
uppermost bar yellow, lower one white. Female is
yellow-green above, yellow below; wing bars
similar to males.
Voice: Song is robin-like in its short fluty phrases,
rendered with a pause in between. The quality is
much hoarser, however. Call is a dry pit-r-ick.
Habitat: Open coniferous forests.
Nesting: 3-5 bluish-green, speckled eggs in a
frail, shallow saucer nest of woven rootlets, weed
stalks, and bark strips, "saddled" in the fork of a
horizontal branch of Douglas fir, spruce, pine, or
occasionally oak, usually at a low elevation.
Range: Breeds from southern Alaska and
Mackenzie southward. Winters in tropics.
Discussion: In late spring and early summer the
Western Tanager, first recorded on the Lewis and
Clark expedition (1803-1806), feeds on insects,
often like a flycatcher, from the high canopy. Later
it feeds on berries and other small fruits.
GLOSSARY
Abiotic Factor – A nonliving part of an
ecosystem.
Adaptation – A characteristic that enables a
living thing to survive in its environment.
Binocular Vision – A type of vision where both
eyes work together to see an object. This creates
fewer fields of vision, and more accurate depth
perception.
Biotic Factor – A living part of an ecosystem.
Camouflage – An animal’s use of its appearance
to protect itself against predators.
Consumer – Any animal that eats plants or eats
other plant-eating animals.
Contour Feather – Feathers that form the
general covering and determine the external
shape and color of a bird.
Downy Feather – A covering of soft, fluffy
feathers, located underneath the contour feathers,
keeping a bird warm.
Ecosystem – All the living and nonliving things in
an area and their interactions with each other.
Food Chain – The path of the energy in food from
one organism to another.
Food Web – The overlapping food chains in an
ecosystem.
FWARPS – An acronym describing the living
(biotic factors) and nonliving (abiotic factors) that
can be found within an ecosystem [Food, Water,
Air, Reproduction, Protection, Space].
Habitat – The place where a population lives.
Hollow Bones – Adaptation specific to bird
bones, utilizing a web-like internal structure, which
makes the bones lighter.
Limiting Factor – Anything that controls the
growth or survival of a population.
Monocular Vision – A type of vision where only
one eye sees an object, creating larger fields of
vision, and less depth perception.
Niche – The role an organism has in its
ecosystem.
Predator – A living thing that hunts other living
things for food.
Prey – A living thing that is hunted for food.
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