This is Bird Note.

One of the most evocative bird voices belongs not to a delicate songbird,

but to a sleek, black and white waterbird.

That's the haunting yodel of a male common loon.

A sound that echoes across northern lakes where loons nest in summer.

With his neck outstretched, the male waves his head from side to side,

sending his eerie calls across forests and open water.

The yodel entices females and asserts his claim to a territory.

Common loons have a repertoire of different calls.

Here's the tremolo.

And this is the eerie whale.

Loons vary the intensity of their tremoloes and whales depending on the situation.

Sometimes they sing only to one another in duets.

But during nighttime choruses, or when flying over another loons territory,

they're singing for all to hear.

Whether it's a yodel, whale, or tremolo,

it's hard to forget the haunting voice of the common loon.

For Bird Note, I'm Mary McCann.