[Andrius]

The VERY first thing you have to do is LOCATE the BIRD'S NEST.

I've eradicated bird mites before and it is NOT EASY & NOT FUN !!!

The nest could be right next to the house or IN the house. you cannot do anything to help get rid of them until that nest is found & removed.

You have to walk around & look for any vents that are broken/open & allowing the birds to get in.
Check around all windows....look anywhere & everywhere outside until you find the nest. (check attic also)

Once the nest is gone then you can do the diamaceous earth.

One time, some bird or birds had gotten into a vent & made a SIX FOOT LONG NEST. I kid u not.
A ventilation cover had broken off & they got in & you know the rest of the story. Bird Mite Hell !

GOOD LUCK !