Wildlife Spotting

The brown one has been in and out of this hole for a few days.
Today the black and white one arrived and it looked like they closed the hole with a mud looking substance together.
Then the black and white one opened the hole again.
The brown one came back and closed the hole again.
Then the black and white one came and opened a small hole in the mud.

I have been searching, reading and looking on images all day trying to identify them without luck.

I initially thought they were male and female of the same species, but after discovering that there is cuckoo bees, I think that is what I have witnessed.

The black and white one look very similar to this spotting.
http://www.projectnoah.org/spottings/10503794