Not sure what to make of this:

ST. LOUIS, Missouri (AP) — Songbirds may be the Sinatras of the animal world, but male mice can carry a tune too, say Washington University researchers who were surprised by what they heard.

Scientists have known for decades that male lab mice produce high-frequency sounds — undetectable by human ears — when they pick up the scent of a female mouse. This high-pitched babble is presumably for courtship, although scientists are not certain.

But it turns out those sounds are more complex and interesting than previously thought.

"It soon became … apparent that these vocalizations were not random twitterings but songs," said researcher Timothy Holy. "There was a pattern to them. They sounded a lot like bird songs."

To make their point, the researchers provided audio recordings of the sounds, which have been modified for human ears. The recordings do indeed sound birdlike.

So what is it the male mice sing?  My guess:

Mr. Trouble never hangs around,
when he hears this Mighty sound,

Here I come to save the day!
That means that Mighty Mouse is on the way!

Yes sir, when there is a wrong to right,
Mighty Mouse will join the fight!

On the sea or on the land,
He’s got the situation well in hand!