I’d only be guessing that it’s pollen. There looks to be an awful lot if it is pollen.
Jeff, thanks. Today when workers were coming back I noticed more pollen on them than I’ve ever seen. I hope you’re right.
G’day Mike, are the bees going straight onto the brood after entering the entrance? Looking at the size of those yellow balls, it looks like they could be climbing through a pollen trap. I’d be inclined to use the coreflute in the top slots so that it forms a solid floor. If you do that, make sure your entrance is sufficient. That way the bees will be able to retrieve the pollen if they need to. That’s assuming it is pollen.
Mike,
Jeff is right on the money. That is pollen nodules … I had pollen trap under my Flow-hive for a month this summer… Pollen comes in a rainbow of colors. 
. Here’s a few pix’s of my collected pollen.
Ta ta,
Gerald
What did you do with it in the end, Gerald?
Dee, I’m hoping to buy some pollen substitute n mix real pollen in with that mix. I’ve seen several recipes on the Internet for this blend. Right now I have it frozen in my freezer.
Hope it works … Guessing I’ll give the colonies the mixed patties this winter as they need it … Any thots or ideas !? We didn’t do much feeding back in the 1950’s n 60’s that I remember.
Have a great Sunday !
Gerald
I wouldn’t give them pollen or protein too early - you risk stimulating brood laying too early. Your local beekeepers may be able to help you with timing, but I would guess around January/February might be good. We can do it in California, but it might not be the best thing in Washington state. 
Gerald, thanks. Now this is very interesting to me. Bees are so thrifty with nectar and spilled honey. Why would they leave pollen laying around? Because they have an over-abundance?
Not quite sure which direction your photo is, nor what kind of hive. It looks like a photo at night taken from the back of a Flow hive. If that is indeed a view from the back of a Flow hive with a screened bottom board and no core flute (white plastic) slider in place, then the pollen is probably falling through the screen when the bees accidentally put their legs through it. In their wisdom, Flow decided to make the screen from #6 hardware cloth, which is one of the sizes used in pollen traps. Just a thought. 
Thanks, Dawn. I think you’re probably right. I removed the corflute following another keeper’s suggestion (concern about adequate ventilation) but have replaced it in the lower position. I don’t like stuff at the bottom of the hive and not being able to get at it easily.
Wise words from Dawn.
See what everybody else in your area is doing. Brood stimulation is useful if you are after an early crop like Canola honey here in the uk. Beware that you might have to feed sugar if there is a dip in income after that. I have pollen dub on all my hives as we are waiting for ivy and there was little brood in most of the colonies two weeks ago.
@Dawn_SD n @ Dee,
Thankz to both of you … I was thinking more putting patties on in January or early Febuary… But guessing as you mentioned checking with a local or two what their bent/idea … I don’t want want Queenie revved up premature !
Today I was busy removing my Flow-Frame super n adding a topfeeder n moisture quilt is just finished for the 8 frame box.
.
Only four more quilts to finish n add … I’ll be just about Done. Kind of relax.
Gerald.
Interesting stuff to try n figure !
Gerald
Jerry, your record-keeping is impressive, and is showing its value. I am impressed! 
Cám ơn ! (Thank you)… I’ve been very lucky to live here all my life. Being a woodsman n nature lover n observer I noticed details in the sequence of seasonal life … I often know what should bloom next but never recorded or documented this info for anything other that my gardening… When I owned n operated a small plant nursery n greenhouses I was sharper on what trees, shrubs n plants bloomed or leafed out next. Some of that was getting LOST in my Gray Matter n getting moldy n hard to retrieve/remember. (You snooze/not use you lose)… 
… This calendar n other logs/records are polishing up my stored/brain info once again. Maybe beekeeping will help me keep my thinking process sharper n useful loooonger ! Took me a time to gain so would rather remember more longer as I get wrinkled n slower 
…
Suppose to hit the upper 70’s today 
. Right now I’d never know that …
Wow ! Am I a chatterbox this morning. I need to record my last 24 hour data here now… Have a great Tuesday !
Ta ta my friend.
Jerry
PS… To keep this bee related I will add. Even my 
are refusing to come out … I just checked . Sun hasn’t got to the apiary yet !