Why Do Hummingbirds Drink Nectar?

This story is a Native American folk-tale akin to 

"The Tortoise and the Hare".

I will summarize.

The Heron and the hummingbird start out as friends who

fish for food in the same waters.

The hummingbird becomes worried that the Heron is eating

more than his fair share so she comes up with the plan for

a race. The winner has fishing rights,

and the loser has to find food elsewhere.

The hummingbird is  quickly in the lead and flies miles ahead.

The Heron is slow and lumbers along.

The hummingbird wastes hours sipping nectar from

a field of red sage. The heron slowly catches up.

The hummingbird speed miles ahead again but then 

figures that she is so far ahead that she can easily stop

and sleep and easily beat the heron to the finish 

in the morning but the heron flies steadily through the night.

Obviously, the heron wins.

And that's why herons eat fish 

and hummingbirds ...

drink nectar.