"So little cause for carolings...

Of such ecstatic sound
Was written on terrestrial things
Afar or nigh around,
That I could think there trembled through
His happy good-night air
Some blessed Hope, whereof he knew
And I was unaware"

The Darkling Thrush, Thomas Hardy

(Yes, granted, the photo is of a Robin and not a thrush, but the sentiments are the same)