Question 2 of 21

What is the single feature that distinguishes birds from other animals?

... Birds are the only animal with feathers. While all birds have wings but not all can fly, some creatures other than birds, such as insects and bats, can also fly.

Question 3 of 21

What bird cannot fly?

... The ostrich is fast on the ground, but cannot fly.

Question 4 of 21

How many known species of birds are there?

... There are about 9,000 species of birds.

Question 5 of 21

Of these species, how many are residents of North America?

... Some 700 live in the United States and Canada.

Question 6 of 21

Which is the largest bird?

... The ostrich is nearly eight feet (2.4 m) tall.

Question 7 of 21

How much can an adult ostrich weigh?

... An adult ostrich can weigh in at over 300 pounds (136 kg).

Question 8 of 21

At the other end of the scale, which is the smallest bird?

... A certain tropical hummingbird is only two inches (5 cm) long.

Question 9 of 21

And what does that tiny bird weigh?

... That hummingbird weighs less than one ounce (28 g).

Question 10 of 21

What species of birds is the longest-living?

... The larger birds such as ostriches, vultures and ravens are the longest-living.

Question 11 of 21

For how long can these birds live?

... They can live for many decades.

Question 12 of 21

How does a flying bird's skeleton differ from that of most other vertebrates?

... It is lighter with fewer bones.

Question 13 of 21

What is a bird's skull similar to?

... The bird's skull is similar to that of reptiles.

Question 14 of 21

How is the bird's skull shaped?

... It's lengthened in the front into two jaws that form part of the beak.

Question 15 of 21

What is the main function of the beak?

... The beak is used for gathering food and as a tool for building nests.

Question 16 of 21

Where are the bird's nostrils situated?

... On the upper jaw are two slits that act as nostrils

Question 17 of 21

Why is the backbone of the bird rigid?

... The rigidity provides the strong support of the back and wings necessary for flying.

Question 18 of 21

The breastbone has a large flat surface, why is this?

... The large flat surface is needed for the attachment of the wing muscles.

Question 19 of 21

Why does a bird have three bones forming a shoulder girdle?

... This structure is unique to birds and prevents ribs and sternum collapsing during the exertion of flight.

Question 20 of 21

What part of the bird's skeletal structure is similar to that of other vertebrates?

... The wing structure consists of an upper arm bone, two lower arm bones, wrist and palm bones and fingers.

Question 21 of 21

Where are most of a bird's muscles concentrated?

... Birds are muscular creatures with most of that muscle concentrated in the breast and upper leg.