Definitely a Mondegreen, IMHO.

I have a 4-CD set called Irish Folk Favourites, which is basically 6 old vinyl Transatlantic label LPs from about 1968-72. One of them is by Sweeney's Men, and has this song on it. Most of the tracks are "Trad. Arr. Woods

My guess is that this guy Woods was one of Sweeney's Men and he wrote the song. In this version, at least, the disputed line is clearly To see what I suffered for your sake, and there's no crow verse, so the song is totally birdless!

MY DEAREST DEAR

Recorded by Sweeney's Men (ca 1970)

My dearest dear, the time has come when you and I must part.
And no-one knows the inner grief of my poor aching heart.
To see what I suffered for your sake. You are to my love most dear.
I wish that I could go with you or you might tarry here.

For my old mother it's hard to leave, my father's on my mind,
But for your sake I'd go with you and leave them all behind.
But for your sake I'd go with you, Oh mother, fare ye well,
For fear I never will see no more while here on earth do dwell.

I wish my breast was made of glass, Wherein you might behold,
Your name in secret I would write, in letters of fine gold,
Your name in secret I would write, Oh believe in what I say,
For you are the girl I love most dear, until my dying day

But when you're in some distant land, think of your absent friends,
And when the wind blows cold and clear, a line or two please send.
But when the wind blows cold and clear, please send it on to me
So I will know by your handwrit how things have gone with thee.

My dearest dear, the time has come when you and I must part.
And no-one knows the inner grief of my poor aching heart.
To see what I suffered for your sake. You are to my love most dear.
I wish that I could go with you or you might tarry here.

Sorry to spoil the fun - the suggestions have been much more interesting than the original words

Here's the basic tune used by Sweeney's Men

MIDI file: MIDI1.MID

Timebase: 480

Tempo: 160 (375000 microsec/crotchet)
Key: G
TimeSig: 3/4 18 8
Name: My Dearest Dear
Start
0000 1 71 127 0479 0 71 000 0001 1 71 127 0959 0 71 000 0001 1 69 090 0479 0 69 000 0001 1 67 127 0959 0 67 000 0001 1 71 090 0479 0 71 000 0001 1 72 127 0479 0 72 000 0001 1 71 090 0479 0 71 000 0001 1 69 090 0479 0 69 000 0001 1 71 127 0959 0 71 000 0001 1 67 090 0479 0 67 000 0001 1 64 127 0959 0 64 000 0001 1 72 090 0479 0 72 000 0001 1 67 127 0959 0 67 000 0001 1 67 090 0479 0 67 000 0001 1 67 127 1919 0 67 000 0481 1 71 090 0479 0 71 000 0001 1 71 127 0959 0 71 000 0001 1 69 090 0479 0 69 000 0001 1 67 127 0959 0 67 000 0001 1 71 090 0479 0 71 000 0001 1 72 127 0479 0 72 000 0001 1 71 090 0479 0 71 000 0001 1 69 090 0479 0 69 000 0001 1 71 127 0959 0 71 000 0001 1 67 090 0479 0 67 000 0001 1 64 127 0959 0 64 000 0001 1 72 090 0479 0 72 000 0001 1 72 127 0959 0 72 000 0001 1 67 090 0479 0 67 000 0001 1 71 127 1919 0 71 000 0481 1 71 090 0479 0 71 000 0001 1 72 127 0479 0 72 000 0001 1 71 090 0479 0 71 000 0001 1 69 090 0479 0 69 000 0001 1 69 127 0959 0 69 000 0001 1 69 090 0479 0 69 000 0001 1 67 127 0959 0 67 000 0001 1 71 090 0479 0 71 000 0001 1 71 127 0959 0 71 000 0001 1 67 090 0479 0 67 000 0001 1 64 127 0479 0 64 000 0001 1 72 090 0479 0 72 000 0001 1 72 090 0479 0 72 000 0001 1 72 127 0959 0 72 000 0001 1 76 090 0479 0 76 000 0001 1 74 127 1919 0 74 000 0481 1 71 090 0479 0 71 000 0001 1 71 127 0959 0 71 000 0001 1 74 090 0479 0 74 000 0001 1 72 127 0959 0 72 000 0001 1 76 090 0479 0 76 000 0001 1 74 127 0959 0 74 000 0001 1 71 090 0479 0 71 000 0001 1 71 127 0959 0 71 000 0001 1 74 090 0479 0 74 000 0001 1 74 127 0479 0 74 000 0001 1 72 090 0479 0 72 000 0001 1 71 090 0479 0 71 000 0001 1 67 127 0959 0 67 000 0001 1 64 090 0479 0 64 000 0001 1 67 127 1919 0 67 000
End

This program is worth the effort of learning it.

To download the March 10 MIDItext 98 software and get instructions on how to use it click here

ABC format:

X:1
T:My Dearest Dear
M:3/4
Q:1/4=160
K:G
B| B2A|G2B|cBA|B2G |E2c|G2G|G3-|-GzB|
B2A|G2B|cBA|B2G |E2c|c2G|B3-|-BzB|
cBA|A2A|G2B|B2G |Ecc|c2e|d3-|-dzB|
B2d|c2e|d2B|B2d |dcB|G2E|G3-|-G ||

Wassail! V