Birds have feathers that help them fly and stay warm. They preen and molt feathers regularly. Birds have fast digestion and eat high protein foods like seeds and insects since they lack teeth. Their light skeletons and powerful muscles allow flight through lift generated by air moving over wings. Birds build nests and care for young through brooding or by having precocial or altricial chicks. There are many kinds of birds including flightless, water, perching, and birds of prey.

1. Birds

2. Characteristics of Birds
 Feathers
 Help birds stay dry and warm,
attract mates, and fly
 Preening and Molting

Preening: the act of grooming
and maintaining their feathers
 Preening spreads oil over the
feathers, which makes them
waterproof
 Molting: process of shedding
old feathers and growing new
ones

Most birds shed once a year

3. 
Two kinds of feathers
 Down feathers  fluffy
feathers that lie next to the
bird’s body
 Keep birds warm by
trapping body heat next to
body
 Contour feathers  stiff
feathers that cover a bird’s body
and wings
 Colors and shapes attract
mates

Streamlined surface helps
bird fly

4.  Fast Digestion
 Birds eat a lot because they need
a lot of energy
 Birds eat seeds, insects, nuts, and
meat because they are high in
protein

Modern birds don’t have teeth, so
they can’t chew

Food goes from the mouth to the
crop, which stores food until it
goes to the gizzard the gizzard
has small stones which grind up
the food so that it can be easily
digested

5.  Flying

Birds have air sacs attached to their lungs
to store air

Most birds have large eyes and excellent
eyesight; birds such as hawks and eagles
can see 8 times better than humans can see!

Wing shape is related to how a bird flies-
short wings for quick turning, long wings for
soaring

6. 
Rigid skeleton allows a bird to
move its wings efficiently

Powerful flight muscle attached to a
large breastbone called a keel

Birds have hollow bones so that
they are light

Getting off the ground
 Air moving around a bird’s wing
changes in speed and
direction, creating an upward
force that keeps a bird in the air
 “lift” is an upward force on a
bird’s wings

7.  Raising Baby Birds

Most birds build nests to lay
their eggs

Brooding act of sitting on
eggs and using body heat to
keep them warm

8. 
Some birds are active soon after
birth; others are weak and helpless
 Precocial active chicks,
such as chickens and ducks;
can stand up and follow
parents around
 Altricial have no feathers and
eyes are closed when born;
cannot walk or fly at birth, such
as hawks and songbirds

9. Kinds of Birds
 Flightless birds

Most do not have
the large keel that
anchors a birds’
flight muscles

Some run quickly
to move around

Others are skilled
swimmers

Examples:
penguins, kiwi,
ostrich

10.  Water birds
 Usually have webbed
feet for swimming or
long legs for wading
 Examples:
cranes, ducks,
geese, swans,
pelicans

11.  Perching birds

Have special adaptations
for resting on branches

Its feet automatically
close around a branch
 Even if it falls asleep, its
feet will stay closed—it
won’t fall off the branch
 Examples: chickadees,
parrots, robins, sparrows

12.  Birds of Prey
 Hunt and eat other
vertebrates
 Have sharp claws on their
feet and a sharp, curved
beak
 Also have very good
vision

Most hunt during the day,
but most owls hunt at night

Examples: owls, osprey,
hawks, vultures