BIRDS

BIRDS

WHAT ARE BIRDS LIKE?

-They are terrestial.

-Most of them can fly.

Main characteristics:

-They have aerodynamic body (their body is shaped in a way that allows you to

move through).

-They are covered in feathers (some are used for flying and other are used preserve body heat)

-They have four limbs: fore limbs are wings and the hindlimbs are scaly legs.

-They haven't got any teeth they have a beak.

-They're bones are thin but strong.

-Many of them are hollow wich makes birds lighter and helps them fly.

-They breathe with lungs, that era linked to little sacks called air sacks

-They are endothermic (they mantain their body temperature).

NUTRITION

-Some are carnivores. (insects...)

-Some are hervivores. (plants...)

REPRODUCTION

-They reproduce sexually.

-They are oviparous.

-They build nests where they lay their eggs,

wich have an impermeable shell.

THE MAIN TYPES OF BIRDS

Birds can be classified into 2 groups: Carinate birds and ratites.

CARINATE BIRDS

-Includes the mayority of birds. (gulls, finches...).

-Most of them can fly.

-Their sternum is very wide and forms a structure

called a keel.

-These keel is able to support the powerfull muscles.

RATITES

-Includes just a few, generally large flightless birds.

-They have not keel or flight muscles.

-Their wings are atrophied.