Hi Hobbyhomesteader! I am so grateful you replied on this thread!!!! Your expertise is exactly what I need! My field is Wildlife Biology and I really dislike not being able to properly identify these critters, or any critter....but Im quite unschooled in the field of entemology! I cannot take a photo of the mites I saw in the bathroom--my camera can't zoom in on something so small and, at this point, the ones I can find that remain are dead and therefore harder to make out details. I can describe them pretty well though and maybe that will help with ID, or maybe rule species in or out. They are beige, almost translucent and about the size of a small grain of sand. Some were even smaller than that. They were out and about in the daytime, crawling around in the billions (literally covering surfaces). I couldnt count the legs but it appeared that their two front legs were the ones most noticeable. I mention this because, in the reading the link you sent me, I learned that the different age stages have different numbers of legs. Unfortunately, the dead ones are mushed up enough by the spray and cleaning that I cant count the legs. I do have an eye loupe so if you have questions that will help ID, I can look further and report back

At this point, I have a few follow questions for you. I *believe* I eradicated the critters from my bathroom, BUT given the misconceptions you cleared up about hosts, I am now concerned that, if i missed even ONE (and how could I not have, right?!?), that the infestation may start anew. Is this a concern? My concern stems from the fact that, although I emptied and thoroughly sprayed my bathroom and cleaned it up, I DID NOT empty the two closets in there. I didnt observe any critters in those areas, hence my decision to do that. Hopefully that was not a big mistake :O
Also, I was assuming that, since these bathroom crawlies were active during the day, that I would also see presence of the mites on my birds during the day. The literature suggests that "they" are active at night, a time when I have not checked....and without positive ID, I dont even know what "they" are! Quite honestly, Im still really confused as to how these mites got in my house; if the birds arent infested, there would be no other way for the infestation to start! We have no bird nests on the house, etc.
I think its safe to assume I should just treat the birds at this point, a smart idea this time of year anyways. Do you have a method for treatment you like most for mites?? Im sure many people on here would love to hear what you recommend for both treatment AND prevention!!!

Anyways, I really appreciate your time reading this little novel Ive posted here...and hopefully with your help I can start to make heads or tails of this!! Many thanks!!!