Today I checked the 3 feral hives within a mile of my hives and they all made it through the "winter" just fine and are bringing in pollen. They are all in hollow valley oak or live oak trees. Four years ago I started looking for feral hives in the Fremont Older Open Space (where my bees roam) and I am now convinced that every oak with a suitable cavity has a feral hive. The ones I found are near the trails since I don't want to wade through poison oak to check on other big oaks. During that time only one hive didn't survive the winter and that was because a high power line crew trimmed some top branches and I assume the chain saw guys killed the hive so they could do their work. This year it's back big time.
So all the feral hives I know about near me are doing very well. I also noticed that of my 5 hives, the 3 that have the most feral genetics (years with local drone input and swarms from feral colony) are showing very little mite drop through the SBBs. The other 2 hives are from silicon valley swarms and they have a heavy mite drop. I'm thinking the feral genetics may shut down brood production more in winter, thus suppressing mites. Does anyone know of any verification of this?