Birds are bipedal,
warm-blooded, egg-laying vertebrates traditionally characterized by
the presence of feathers. Their forelimbs are wings. They
have hollow bones. They vary in size from tiny hummingbirds to
the huge Ostriches. Authorities disagree as to classification.
Some maintain that some birds are varieties or subspecies of another
while others maintain they are separate species. Depending on
which system is used, there are between 8,800 and 10,200 living
species. Another 120 to 130 have become extinct over the past few
They show tremendous diversity. Most are active during the day, but
others are active at night. Still others prefer the twilight
hours. They have filled a great many ecological niches and
different species have different diets. Birds feed on plants,
seeds, nectar, insects, small mammals, fish, carrion and even other
birds. Most life on land, but others spend almost all their time
at sea. Many frequent ocean shores, while others live around
rivers, lakes and ponds. Some birds migrate long distances and
some can stay aloft for days at a time. No other vertebrate has
demonstrated such great flexibility or enjoyed such great success.
Recent fossil discoveries have revealed that many dinosaurs had
bird characteristics, such feathers, hollow bones and beaks.
Other fossils reveal bird behavior, such as brooding and sleeping
positions. Today scientists are in almost universal agreement
that birds descended from the dinosaurs.
- 150-148 MYA
The Archaeopteryx is considered to be one of the most
important ever discovered. Archaeopteryx is considered by many
to be the link between dinosaurs and birds. It had teeth and
claws, but it also had feathers and wings.
robusta - 135 MYA Protarchaeopteryx
was a small, feathered, bird-like dinosaur that lived in China. This
animal is considered to be more primitive than Archaeopteryx
However it was not an ancestor of the famous "first bird," as it
lived ten million years later.