Roger,
Some tunes are better suited to fiddle than Flute. A tune like Drowsey Maggie, while a contant workout for the fingers on a flute or whistle, falls under a fiddlers fingers. Other tunes like The Mountain Road and Mary Ramsey have that darned B in it. I have seen people play the B an octave above or a roll on a harmonizing note like G. Other tunes like The The Fox Hunter's Reel are better on the fiddle in A, while better on the flute in G, although most fiddlers can play it in both keys.

Brían