@jhalloran: The opening song is a slightly different and very shortened version of "The Well Below the Valley":

A gentleman was passing by
He stopped for a drink as he got dry

At the well below the valley-o
Green grows the lily-o
Down among the bushes-o

Me cup was full up to the rim,
if I were a [stoop?] I might fall in

At the well ...

He said "Young maid you're swearing wrong,"
for six fine children she had born

At the well ...

If you be a man of noble esteem,
You tell to me what happened to them

At the well ...

Two buried beneath the stable door

At the well ...

You'll be seven years a-ringin' the bell,
but the Lord above he save me soul
From all this hell

Green grows ...

Considering the content of the film and what happens right afterwards, it's really quite a fitting choice of song.