The maintenance of wing

There is a need in a machine which calls
For others to ensure it does as bid.
On breakdown, it inevitably falls
To them to find out where the faults are hid
They put them right, though leaving still one thing
That each machine requires to be of use -
And this recalls the maintenance of wing,
Which all birds must perform, without excuse.

The owl who hunts does not do so unless
She keeps her wings fine-tuned at flying pitch -
An irksome burr the more, a preening less
Is greater far than any minor glitch,
For it may mean the losing of a prey,
Or cause control to falter in the air,
Spelling the end of peerless mastery,
Bringing her crashing down near danger's lair.

The vital toil the owl performs each day
Cannot be done by proxy for her sake.
Her maintenance of wing points us the way
That brute machines necessitate we take.