A living and breathing answer to a recurring crossword clue
Now keeps me wide alert:
Small songbird [four letters]…… give up?
Wren (for the puzzle) and Carolina Wren for hereabouts.

Filling in this answer is the easy part,
Catching a sighting is quite a different matter.
The field guides try to help:
Brown above; buff below; white line
Running through feathers over the eye; upturning tail.
The seeing sounds so easy, clear, and evident
So far, but read on.
Diminutive, reclusive, thicket-dwelling, secretive,
In tangles and old brush heaps
And generally hidden…… the seeing seems more like idly hoping,
But read on further.
Song is piercing, musical, rollicking, whistling, bubbling,
Lasting all the day throughout the year.

So they are something for catching sound of,
Better heard than seen.
It takes but a stepping outside and a listening,
A switch in sensing from eye to ear,
To catch this greeting, and gather hints and clues
For filling in the blanks of one of nature’s most engaging puzzles.