“Song in the Thicket” by Manly Banister. Cover art by W. H. Silvey.
Yes, “Manly Banister” is indeed the author’s name. He appears to have had several, so it’s a good bet this was a nom de plume. (For comparison, his other names include “Gregg Powers” and, curiously, “Val Seanne.”)
Google him. He … actually published a hell of a lot between 1942 and 1980.