This is bird-note.

White-throated sparrows are shy birds, but on warm days in late winter and early spring the spirit comes upon them and the thickets are rubbed into song.

Those cheerful whistles are easily set to human words.

Old Sam Pee-Buddy Pee-Buddy Pee-Buddy?

Or...

Oh, sweet Canada, Canada, Canada.

But something has changed since those classic memory aids were coined.

Listen to this recording made in the early 1950s.

This song begins with two long pure notes.

Old Sam...

Oh, sweet.

And concludes with three triplet groups.

Now listen to this recorded 60 years later.

Hear the difference?

It is very subtle.

This bird sings a simpler shorter song with an abbreviated ending.

In the 1920s, the white-throated sparrows' longer song was the most common.

But bird-song, like human language, changes.

By the 1960s, it had become extremely rare.

Researchers suggested that the classic song had died out to be replaced by the shorter version.

Listen in city parks, suburban backyards, open woods, and see what the birds in your neighborhood are saying.

For bird note, I'm Mary McCann.

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