I think they are little browns too...and being young ones would explain why such nubs for teeth....and so super tiny!My guess might be Little Brown Bat (Myotis lucifugus).....and that you have a young one, or more than one. They are the most common small bat here in Western Wa and like to get in attics or under shingles to have babies and you can get a number of females together to form a nursery. Can live for 30 years, believe it not.......I just love bats!
The first one was TEENSY tiny!
These are also dark brown, not light brown as most pictures on the web...and it is so weird they live so long!
They are cool...I wish I knew where they were coming from...maybe the clue is how small they are...maybe the adults (still small!) are too big to squeeze into the enterior of this house...an adult can fit through a nickle sized hole, and these were much smaller...like they'd fit through a dime sized hole for sure !