I've noticed that bottom boards come with 2 different spacings. 1 is "taller", and 1 is "shorter". Every picture I see shows the "tall" side being up - towards the hive for the entrance, and the "short" side being down. My screened bottom boards (which are not "reversable") have the tall spacing also.
However, as I watch returning field bees entering the hive, I've noticed that they have a hard time climbing up into the frames with the taller spacing. Most of them walk all the way to the back of the hive and climb the back wall. Or they climb the sides. With an entrance reducer on, they will climb it.
I've also noticed that they make several attempts to reach up and grab other bees to lift themselves up into the frames, as they march towards the back. Sometimes they are successful, but mostly not.
So I flipped a couple of bottom boards to the "short" side. In these hives, as the bees land and march in, they climb directly into the frames anywhere they choose without effort. The entrance is far less conjested this way. It seemed to eliminate the massive traffic jam at the entrance that occurs on a busy day as the bees all look for a way to climb up.
So my question is, what is the reasoning behind the height spacing of the bottom boards? Why are there 2 different thicknesses? Is there a "right" and a "wrong" side of the BB? If so, why?
Thoughts and comments appreciated. Thanks.