The tune in question is a tune, not a song (hence no words to quote); McGlynn learnt it from Jackie Daly.  It isn't the best-known "Blackbird", but is quite likely related to it; it's really a hornpipe played slowly rather than an air per se.  Although it's possible that there may be tab out there somewhere, I think you'll probably have to work it out for yourself.  I don't have time to track it down, but you could do your own detective work: first stop is  The Fiddler's Companion,  where you can find information about tunes called "The Blackbird" and their alternative titles.  Next, try  J C's Tunefinder,  where you can look for examples of the various tunes in a number of formats including staff notation and midi; with luck you'll find the piece you want there, though you'll have to trawl through a good bit of material.  There are plenty of other places to look, too, but these two are generally the most comprehensive for such things.

Malcolm