Last week, I was with other birders and we were enjoying (with bittersweet thoughts) the last bird songs of the season. The season of the dawn chorus was ending.

A few thrushes were still singing, and we heard hermit and Swainson’ s thrushes and also the song of the veery, another thrush. These are considered the best singers. The “dawn chorus” has tapered off to a few individuals. Soon it will be gone.

I have wondered why the hermit thrush’ s song is considered the most beautiful song of all. I suppose it’ s because its harmonics are so pure. The notes of the Swainson’ s thrush sound “blurry,” but still the song is beautiful as it goes up the scale.

And the veery’ s song is thrilling to hear as its notes spiral down the scale. Mnemonics that help birders learn the veery’ s song are “it echoes down the rain barrel” or “the veery spirals down the drain.” The veery’ s notes are “blurry,” also.

I am a semiliterary thug when it comes to music, but my sister Elizabeth Kellogg, a professional cellist, knows about music. She lives in Virginia. I called her up and asked her what makes some notes sound pure and other notes sound “blurry.”

I told her that hermit thrush songs are considered the most beautiful with their pure notes, but that I think the veery’ s and the Swainson’ s thrush songs are just as beautiful despite their “blurry” notes.

I explained that thrushes sing several notes simultaneously. They sing with their syrinx, not with their larynx as we do. The syrinx is located at the juncture of the two bronchia and goes into both. There are rippling membranes there.

Elizabeth said, “With the cello, if you put your finger halfway along the string, it will play an octave higher. So I would guess that the hermit thrush would shorten its syrinx membrane on one side, in fractions of two — whereas the veery may shorten its syrinx membranes on one side by fractions of five or seven. They all must be dealing with tiny measurements within their bronchi, though.”

I was impressed. Ornithology and music have their affinities. I have about 275 days to ponder this until next May, when the dawn chorus of the thrushes will start up again. I can’ t wait.

For information on Fields Pond Audubon Center, call 989-2591.