“They apparently come in various sizes...”
Do they gather in groups? Pairs, perhaps?
My understanding, based on some experience, is that they mate for life and are almost always found as secretive, constant companions - often hidden away from sight in a type of "double nest."
More research is required.
I'm doing my part, with real passion, but I am only one scientist...
Please volunteer, while there is still time to uncover these secrets.