Bill,

You're quite right about the bodhrán being used by the wren boys. It was only after it appeared in John B Keane's "Sive" and then taken up by Ceoltóirí Cualann (O Riada's creation) and the Chieftains who were a development of Ceoltóirí Cualann that the bodhrán found its way into mainstream Irish trad music.

The only details that I'm less sure about are the woven willow frame and whether the bodhrán was used to beat the bushes. Given that most of the time the wren boys didn't have a real wren anyway, it sounds quite plausible: the wren was no doubt a discriminating musician which flew away while the bodhránaí was still getting out his cipín.