Do you know all birds protect （1）

themselves

themselves

（they） by listening and watching out for danger？At the（2）

smallest

smallest

（small） sign of it，they will fly away.Birds that cannot fly are often able （3）

to swim

to swim

（swim） fast，or run quickly.Some birds make themselves look （4）

bigger

bigger

（big） and more dangerous by fluffing their feathers.
   Another important （5）

protection

protection

（protect） for many birds is their colours.Their feathers often have colours that match the things around their nests.Some birds change colours with the seasons.In winter they are white（6）

to match

to match

（match ）the snow.In summer they are brown to match the ground.
   People sometimes kill the birds without meaning to.When people cut down forests （7）

to build

to build

（build） houses and factories，they destroy the homes and food of birds.If the birds have nowhere else to go and nothing to eat，they （8）

will die

will die

（die）out.
   Pollution may cause some birds to die.Birds that eat fish from polluted water get poison in their bodies.Then they cannot lay healthy eggs.New birds can't born.
   Now people protect birds by passing the laws to control （9）

hunting

hunting

（hunt）and pollution，by setting up some special parks where all the birds are safe from hunters，and by teaching people （10）

to care

to care

（care）about birds rather than kill them.