The item in "The Musical Times" concerning J.J. Niles's "Carol of the Birds" doesn't offer much detail. The article is a description of a collection of choral arrangments of songs from Niles, published by Chappell. No title for the collection is given, but it is described as "a batch of pieces by John Jacob Niles, a well-known American writer and arranger."

The author continues that the collection "includes some for two-part chorus, S.A., and some for three parts, S.S.A.; with or without a soloist. The style is simple, largely diatonic, naive, suiting the folk-songs or those which adopt that amiable, unexciting style which we associate with the bulk of such songs from the English-speaking lands." (!)

"A good many are carols; of the S.A. [soprano-alto] batch, 'Sweet Marie and Her Baby' and 'The Carol of the Birds'. The latter is a capella (the other S.A. items having piano accompaniment), and has an s. solo, the other parts humming: alleghretto 6-8.

So, it's entirely ambiguous as to whether Niles wrote the piece or not. They are his arrangements (with apparently typical hums and "ah"s sprinkled throughout).

~ Becky in Tucson