That is:—

If the cuckoo sings a month before May-day,
I will sing a month before August.

Calan Mai, May-day, abbreviated to Clamme, according to the Old Style, corresponds with our 12th of May, and the above saying means, that there would be such an abundant hay harvest if the cuckoo sang a month before May-day, that the farmer would himself sing for joy on the 12th of July. It was the custom in the uplands of Wales to begin the hay harvest on the 1st of July.

The above I heard in Montgomeryshire, and also the following:—

Mis cyn Clamme cân y côge,
Mis cyn hynny tyf mriallu.

That is:—

If the cuckoo sings a month before May-day,

Primroses will grow a month before that time.

I do not know what this means, unless it implies that early primroses foretell an early summer.

But, speaking of the song of the cuckoo, we have the following lines:—