After a week of bitter temperatures and more falling snow, it’s hardly surprising that my thoughts turn to the north (and I don’t mean Boston).

This Sunday night on “The Lost Chord,” we’ll have a couple of pieces from Finland, both of them inspired by the region’s avian life.

Einojuhani Rautavaara wrote his “Cantus Arcticus” in 1972. He described it as a “concerto for birdsong and orchestra.” The work incorporates tape recordings made on the bogs of Liminka, near the Arctic Circle. More than just a gimmick, the piece is an inspiring triptych that manages to transcend its potentially new age conceit. The final movement takes the form of a long crescendo for orchestra, which incorporates the song of whooper swans.

Swans, of course, also played a crucial role in the creation of Jean Sibelius’ uplifting Symphony No. 5. The composer was moved to write the grand theme of the symphony’s finale after observing a flock of swans in flight over his home on the shores of Lake Tuusula in Järvenpää. The tolling French horns unfailingly generate a glow of hope and optimism. Such noble music! I don’t mind sharing that this is probably my favorite symphony.

Wait a minute – the Symphony No. 5 is standard repertoire. What’s this doing on “The Lost Chord?”

In 1995, conductor Osmo Vänskä recorded Sibelius’ first thoughts on the symphony, as it was heard at its 1915 premiere. Though the work was extremely well-received, Sibelius became increasingly dissatisfied with it, as he prepared the manuscript for publication.

In what must be one of the most amazing feats of revision ever, he crafted from the comparatively rough material the masterwork we know today. When you hear this original version, you will marvel at the composer’s clarity of purpose, his remarkable objectivity, and just how hard he worked. It’s almost like a completely different piece, one that uses the same recognizable themes, but completely rethinks the structure and, at times, the orchestration. Listening to certain passages is like strolling across familiar terrain. Then the ground shifts, and you find yourself walking down a strange path. If you haven’t heard it, definitely make a point to check it out.

If, like me, you find yourself watching the Academy Awards at 10:00 tomorrow night even as you wonder why, “The Lost Chord” will be rebroadcast Wednesday evening at 6; or you can listen to it later as a webcast at http://www.wwfm.org.

PHOTO: Finnish music takes wing, on “Snow Birds”