A Tale about a Wagtail

This is a wagtail observed bathing  by the riverside....
Some fotos of this ritual and a video...

Stepping into the water....

Head down into the water.....

 Flopping the wings....

 Standing upright again, ready for another round....

 ...stepping back onto the sand and cleaning the feathers, under one wing....

 ...shaking the water off....

 ...under the other wing - shaking the water off....
...airing the tail....

 ...shaking the body again...

 ...now cleaning the upper side of one wing....

 ...shaking the body, the wings and the tails....

  ...now cleaning the upper side of the other wing....

...then shaking and flying away....

My questions:
Does it do it regularly?
To keep the feathers in good condition?
Does it like it?
An interesting fact: after bathing some birds protect their feathers using special waterproof oil that comes out of a gland under their tail.