Red-rumped Swallow, コシアカツバメ

After a quiet morning in the woods I was about to get in the car when this bird came to stop on the wire right in front of me.

After a few minutes he or she nose-dived down to a muddy corner of an unused construction site

  

The bill full of mud - that means a nest is in the making somewhere...

The bird came back to sit in front of me several times. It was calling loud for a while and yes... another one showed up.

It is hard to tell, but the bird on the left seemed to have a slightly shorter tail. Would that be the female then, and the bird on the right her mate?

I waited on the mountain road to see them collecting mud from the car. Not too long, they seemed reluctant to return to the nest. 

Good luck you two!