Reading Your Sticky Boards in the Winter

Sticky boards (mite trays) are an easy way to monitor Varroa mite levels in your hive – easy for you and easy on the bees since you don’t even have to open the hive. The mite tray is inserted below a screened bottom board and examined after days of normal colony life, with no beekeeper activities. This gives an accurate count of how many mites naturally dropped during the monitoring period.

It’s difficult to swap bottom boards mid-winter, so if your bees are snug on top of a solid bottom board, you may have to wait until next year to spy on them with a screened board. But if you already have a screened bottom board under your hive, try using it for some winter-time detective work to check on your bees.

Simply counting the hapless mites that tumble down is not all you can do with sticky boards.

Winter is a fine time to begin studying sticky boards. You’ll be less pressed for time, and the smaller bee population reduces the total amount of junk on the board. And most of us are itching for more beekeeping tasks to do in the winter anyway!

Sticky board checks are usually done over three days, which provides a more representative average daily mite drop. Winter sticky boards have far less falling onto them, and can be left in for a week or more and still be perfectly readable. 

What do you need?

1. A screened bottom board: You can install yours on top of a solid bottom board, but you can also use one all by itself. Using both boards together works very well; they can be left in place year-round, with bees entering the screened bottom board's usual entrance at the front of the hive, and the solid bottom board’s entrance facing backwards and covered by a strip of wood or plastic, so no bees mistakenly wander in there. The open slot for the sticky board should face the back of the hive.
2. A mite collection surface: A flat varroa tray works best, and a plastic one can be cleaned and reused repeatedly.
3. Any kind of cooking oil, baby oil, or spray-on oil (like Pam).

Apply a thin, but complete, layer of oil on the top of your tray. Slide the oiled tray into the slot at the back of the screened bottom board. If you can, close the back slot to keep bees and mice out. Then, wait!

What will you find when you check your bottom board?

A magnifying glass will help you identify what’s on the tray. Here’s an overview of what you might see, what it means if you find it, and what to do if you spot a problem.

General debris

The first thing you'll notice are the stripes of the debris. Each stripe corresponds to the space, or "seam" between the frames overhead. Seams with no bees in them don’t generate garbage, so they tell you where and how large the cluster of bees is. Over time during the winter, the location of the stripes will migrate and gradually expand as the bees' spring build-up gathers steam. A good way to make a record of the pattern on the board is to snap a picture each time you peek, which allows you to compare the boards in a sequential fashion.

Mites

One small hive beetle and four varroa mites with typical wax bits dropped when bees uncapped honey to eat.

 You'll probably see some varroa mites. If you have done a good job of mite control in the late summer, fall, and winter broodless period, you may be gratified to find very few of them. If you have recently treated for mites using oxalic acid, you may see a flurry of dead mites falling — but this is not representative of the passive daily mite drop. It’s just good proof your treatment was effective. However, if you see an average daily drop of 10 or more mites, unassisted by a recent miticide treatment, another oxalic treatment is recommended. Another mite treatment that will work during cold weather is Apivar, as long as the strips are within the cluster and the bees are making contact with them.

Wax scales

Wax scales are particularly fascinating: Worker bees have eight glands on the underside of their abdomens that secrete whitish scales of beeswax. These pale oval objects look like tiny fish scales. If you hold a sticky board in the sun and tilt it just right, these flakes will sparkle and catch your eye if they’re there, even though they are nearly transparent. 

Four newly made white wax scales that fell.

Young worker bees in the 8th to 12th days of their lives are the best wax secretors. Seeing wax scales on a sticky board indicates a small but growing population of newly maturing bees whose bodies are making wax right on schedule.

In mid-late winter there isn't much need for comb-building, so the new wax flakes are likely to fall down as a form of hive waste. This is a hopeful sign of the approaching spring, and a promise that all is proceeding normally in the hive above.

Wax debris and bigger pieces

The very fine, brown, granular particles you’ll see are bits of wax cappings from honey cells, chewed away and dropped as honey was consumed. The darker the wax, the older it is. 

Larger crumbs of wax may indicate smash-and-grab robbing. This is seen when a hive is weak or dead, and then is robbed by other bees. This can be confusing if you saw busy entrance activity in front of your hive on warm winter days, but the coming-and-going activity you observed may have really been robbers removing whatever honey they could steal, and dumping wax scraps as they greedily emptied the cells.

Actual pieces of comb on the sticky board (or resting on the screened bottom board itself) may indicate a mouse is living in the colony. You’ll also see mouse droppings and bits of grass falling from the mouse’s nest. You can separate the boxes on a warm winter day to find and remove the mouse — then be sure to add a metal mouse guard. Mice will likely leap out when you open the hive, so be sure your pants cuffs are tucked in or you may have to shake a scared mouse out of your pant-leg! 

Pollen

Pollen comes in many colors, but usually looks like golden or orangish grains, which will be wet due to the oil they’ve absorbed from the board. Since adult wintering bees almost exclusively live on honey, evidence that pollen cells are being opened means that nurse bees are in search of the proteins and fats contained in pollen to feed to new larvae. They need these nutrients to create brood food. So bits of pollen on a screened bottom board strongly suggests that you have a laying queen in the cluster above! 

Small hive beetles

Adult small hive beetles live through the winter within the bee cluster. A small number of these black beetles will die, drop, and will be found on your tray (or at least pieces of them may be found, with whole dead beetles getting stuck on top of the screen.) It's their slowest period of the year and you shouldn't see their larvae on a tray until late spring. 

Two varroa mites, one small hive beetle, and numerous wax bits.

Various bee parts

While seeing bee parts is common, the parts you spot may reveal important information about the colony. Finding bee legs and wings is very normal. These were separated from the dead bodies of bees that died during the previous weeks, and now lay on top of the screen. They don’t necessarily indicate a problem, since there is an inevitable pile-up of corpses when bees keep dying during the winter, but it is too cold for the undertaker bees to fly them outside. On warmer days, as bees tug on corpses to chuck them out, sometimes parts break off. 

In Northern areas, finding many headless bee bodies may mean a shrew has been in the hive. Shrews like to eat bee heads and the muscles inside the bee thorax. Unlike mice (who are just looking for a warm home with some honey to eat) shrews are tiny critters with very specific appetites. They will exit the hive in spring when the cluster begins to move around. It's hard to keep them out unless your mouse guard has holes no wider than 6mm.

Inspecting the debris that filters through a screened bottom board and lands on a sticky board can help diagnose hive issues and let you know if your bees are on the right track. 

After inspecting the sticky board, scrape off the debris, re-oil it, and return the board to the slot to start collecting another week’s worth of materials. 

When you come back and pull the board again, you can read the latest story of what’s happening in the winter cluster. There’s always something to learn about your hives, and practice makes spotting the differences and changes even easier. Explore our Beekeeping Guide for more tips and information.