Here are the lyrics copied from Voices from the Dust Bowl: The Charles L. Todd and Robert Sonkin Migrant Worker Collection, 1940-1941 at the Library of Congress:

BEAVER CAP, SIR
Collected from Bill Jackson, Arvin, California, 1941

I went to town the other day
To buy me a hat, Sir
And everything that they put down
It was a beaver cap, Sir.
Too la loller whack a loller
Too la loller day, Sir.

I went home that very night
I laid it on my bed, Sir
Every time that I woke up
I tried it on my head, Sir.
Too la loller whack a loller
Too la loller day, Sir.

I went to work the other day
A-feelin' mighty flat, Sir
When I come in my Mother'd set
A hen in my old beaver cap, Sir.
Too la loller whack a loller
Too la loller day, Sir.

I picked them eggs up one by one
You bet I had some fun, Sir -
Threw them at my mother's head,
They fanned her as she run, Sir.
Too la loller whack a loller
Too la loller day, Sir.

My wife got mad the other day
She took me by the nap, Sir
Threw me right out in the yard
And stomped my beaver cap, Sir.
Too la loller whack a loller
Too la loller day, Sir.