Which phrase best describes how the speaker in “a narrow fellow in the grass” feels about snakes?

He fears them.

Explanation:

The first four lines of the third stanza show that the speaker feels warmth and friendliness toward many wild animals:

"Several of nature’s people

I know, and they know me;

I feel for them a transport

Of cordiality."

The last four lines of the same stanza show that the speaker feels frightened when he sees a snake.

"But never met this fellow,

Attended or alone,

Without a tighter breathing,

And zero at the bone."