One of my hives appears to be very close to harvest. Every day there is noticeable difference in the amount of frames being filled and I think the bees may be close to capping some soon, if they haven’t already started. This hive appears, from my observation, to be in very good shape. This is the largest number of bees we have seen in it and this would be our 1st harvest coming up. I noticed on the side view window, yesterday, some white substance, that appears to be liquid, but very thick and sticky because it is not running down the window. Any ideas as to what it could be? My hope is that it is nothing harmful. I have attached pictures from yesterday, March 28th of the side window and frames and then another picture of the side window from today. Thank you.
Going out on a limb here. 
It looks very much like powdered sugar. Have you done a sugar roll mite count recently? Or even done a “mite treatment” with a ton of powdered sugar?
Nope. I have not seen any mites or done any treatments. Could it be royal jelly or beeswax?
I would think that royal jelly is highly unlikely. It is very energy-expensive for nurse bees to make, and they seem to be careful about confining it to the brood box. I suppose wax would be possible, but that side of the hive would have to have got very hot to melt wax onto the window. Wax is made as flakes underneath bees, not as blobs. It is also energy-expensive, so they are usually quite careful about how they use it.
Hopefully somebody else will have a helpful idea for you. 
Thank you, I appreciate your input. The weather has been in the 80’s here the past week with about 80% humidity. Not sure how hot it gets inside the hive at those temperatures.
I will watch for more input.
I have seen that on my observation window too. I thought it was wax put there by the bees. I hadn’t fed any sugar or used any other additive in the hive when I observed it.
Thanks Dan, glad I’m not the only one that has seen something like this.
Actually, I have thought about it a bit more, and reckon it is probably the start of bridge comb (I think that is the name of it), that you sometimes encounter between the wall of the hive and the honey super on standard frames.
I hadn’t even thought of that! I think you may be right. Might be time to put on another brood box.
Very smart. Sounds quite likely to me. Glad we have some really intelligent people on here. 
Or a super on top of the Flow super. It works. I have done it. 
Just be aware that it’s spring time where you are. Instead of thinking about extra brood or honey boxes, it’s better to think about swarm prevention. Use the extra brood box for a likely split you could be making in the near future to prevent swarming…
Thanks All for the help and tips.
You’re welcome @smithfam, I love your photo of that bee with those huge pollen sacks. You would have to speculate that that is the maximum load a bee could carry.
it’s definitely wax. I have seen similar on several of my hives. Also once when I housed a swarm into a new hive- overnight the swarm was clustered outside the hive pretty much covering it. By the next day they had all moved in but they left wax just like that on the outside of the hive. It’s still there a year later. In that case the swarm was producing so much wax it seems they just had to get rid of the excess. You see globules of wax like that left on leaves and branches where swarms have been clustered for a few days.
By the looks of that hive it is absolutely booming- and the bees must be in wax production mode.
I am so excited. We just started beekeeping last year, getting our 2 NUCs at the end of April 2017. The past 2 months our bees have been very busy and the hives seem to have exploded. This will be our 1st honey harvest from 1 of our hives.
Scrape a bit out and have a look
@Semaphore is correct. Had a hive recently put some of these wax bits onto the observation window and bingo, a week later they had brace comb built from the window to the flow frame. Almost like they were looking to build out spare space while we had a good flow on.
They started putting more wax dots onto the window, but after I harvested and the major flow slowed down, they left it alone.
Still have the bit of brace in there.