From the sheet music at Indiana University: http://purl.dlib.indiana.edu/iudl/lilly/starr/printable/LL-SSM-2-015-0247-01:


WHIPPOORWILL
Words, Thomas Gregg. Music, M. H. McChesney.
Detroit: C. J. Whitney & Co., 1871.

1. The sun has sunk beneath the west, and dark the shadows fall.
I'll seek again my forest home, and make my evening call.
The zephyr in the grove is hushed, and every leaf is still,
So I will seek my wild retreat and chant my whippowill [sic]*.

CHORUS: Hear the call from yonder hill
Echo through the forest still.
Each soft note the pulses thrill.
Sing on, plaintive whippowill.
Hear the call from yonder hill
Echo through the forest still.
Haste and seek your wild retreat
And chant your whippowill.

2. Dim night, with sable mantle spread, envelopes field and flood,
And stars with pale and yellow light shine out on vale and wood.
My mate too has begun her strain upon yon distant hill,
And I will seek my leafy bow'r and tune my whippowill.

3. The watchdog has retired to rest. The curfew's toll is done.
No sound is heard in these deep shades, save my shrill voice alone;
Or in yon wild and lonely glen, the tinkling of a rill;
So in these peaceful solitudes I'll chant my whippowill.

4. It is the song which God has given. I'll sing it in His praise.
Of all within this forest bower, mine are the sweetest lays.
Then whippowill shall be my song in vale or on the hill.
Each evening at the twilight hour, I'll tune my whippowill.

[* Note: although the title is WHIPPOORWILL, the spelling "whippowill" is used throughout the lyrics.]