I have heard three separate cuckoos this year (reminded above) but alas as we all I haven't been anywhere to sing about them. From the singing of Shirley Collins and my memory

My bonny Cuckoo I'll tell you true
That through the groves I'll rove with you
I'll rove with you untill the next spring
And then my Cuckoo shall sweetly sing

The Ash and the Hazel do mourning say,
'O Bonny Cuckoo don't go away
Don't go away but tarry here
And sing for us throughout the year'

Cuckoo, Cuckoo pray tarry here
And make the Spring last all the year.