There's a short (~30 sec) clip of the Priscilla Herdman et. al's rendition of the song via Allmusic.com (link) or the whole thing with Amazon music.

Since I don't have Amazon Music, the best I can do is offer a transcription of that intro. Maybe the chorus matches the lines provided above, but the intro goes:

Chickadee, chickadee, chickadee-dee
Singing in the sleeping trees
Chickadee, chickadee, chickadee-dee
Soon they will be waking

When the snow melts away
The winter finds you on your way
Who will come unto me
Sing each day merrily