Canine Home Improvement

I got home from work Friday - I saw that the Dog Walker had been by at lunch but Abby didn't come to the door to greet me which was unusual.

As I walked in the dining room, I spot this piece of wood on the floor  ???

It looks like the new trim from the kitchen, put up after the new tile went in and before the new cabinets go in and walls are prepped and painted. 



Yup. But How?  And Why?