Ideas?

[Toại Như Đào]

Hi there. I can use some help again. Thanks for being so helpful in the past. 

Any idea why the bees are all trying to get into this top box by a tiny crack which I’m not sure they even fit in. I took the hive box apart yesterday (only to find the bottom box had a small hive w a few drone brood). There had been a queen cell down there abt 10 days ago but appears she’s been hatched and no eggs nor her were to be found anywhere.  They’ve been doing this since I’ve reassembled the boxes. So any thoughts of what gives to why they’re mesmerized bees w the top box?  Is this robbing?  Is there a queen/swarm up there?  All ideas appreciated. Thanks in advance again. 

[Gerald Przybylski]

Bees are greedy.  They exploit unguarded entrances (knot-holes, gaps
where the edge of a box is damaged, top-entrances) with the intent of
robbing them of honey,

Scraping the build-up of propolis off the top and bottom surfaces of
boxes generally makes them fit together better - minimize gaps.
If you have a knot hole, fill it.
If you have a damaged box, repair it, or retire it or duct-tape the seam
or painters-tape the seam to thwart robbers.
The bees taught me they don't want top entrances or vent gaps at the top
of the hive. They propalized them closed.

If your colony beards too much on hot summer days, try insulating the
top, especially if the box is out in the sun.
The test is to put your palm on the top cover. If you palm gets burned,
it's too hot and needs insulation under it.  In summer some afternoon
shade is probably welcome.
Sun is your friend in winter.