Integumentary System

  A bird’s integumentary system includes skin, feathers, beaks, toenails, and scales.

  The skin is composed of three layers: epidermis, dermis, and hypodermis. Appendages grow from different areas of skin. They are made of materials like keratin and carry out specific functions.

• Some skin is covered with feathers. These lightweight body parts keep birds warm and help them fly.

• The beak includes two bony projections called mandibles (upper and lower bills). They are covered with a layer of keratin.

• Bird toenails come in different shapes and sizes. For example, woodpeckers have sharp, pointed toenails while grouse toenails are blunt.

• Like reptiles, birds have scales. These scales protect their lower legs and feet, creating a shield against scratches and scrapes.