Paul...

The nursery rhyme is...

Two little dickie birds,
Sitting on a wall;
One named Peter,
One named Paul.
Fly away Peter!
Fly away Paul!
Come Back Peter!
Come Back Paul!

The rhyme was first recorded when published in Mother Goose's Melody in London around 1765.

A male White Wagtail...

This is the remaining one of a pair I was photographing....
as they fed along the top of a moss and ivy covered wall....
chez nous.
The other was between the two clumps of ivy....
and very suddenly left...
my last picture was of this one...
before he flew off, too!!