The Flight of the Duck

The miracle of feathered flight's
A mystery that is vexing,
For a certain aspect of the skill
Remains to me perplexing.

I understand that wings cause lift
To lofty heights and then some,
And how an airplane's props provide
The thrust that gives momentum.

But I've always failed to comprehend
Just how a Northern Shoveler
Can fly so quickly through the air
Without a front propeller.

by Lone Dog