This is the traditional English tune Cuckoo's Nest, played in B minor on my A/D Hohner Preciosa for melodeon.net's Tune of the Month. This is roughly the way I play it for my Morris team, which dances it as a Fieldtown jig, though I usually play it on my D/G box in E minor. But the Preciosa is so lovely, so tiny, and has such a big sound, and I haven't shown it off yet despite owning it for almost two years now!
