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Thermal imaging for beekeepers

Last week, a dusting of snow showed me exactly where the cluster in my top-bar hive had gathered. Dead center on the uninsulated gabled roof were two circles of meltwater, so I knew the cluster was right below it. “Aha!” I said. “When my Flir One thermal imager arrives, I will test it on the top-bar hive.”

Sure enough, my very first thermal image showed the cluster centered top-to-bottom and left-to-right. There is something reassuring about viewing it, all snug and glowy, in the middle of winter.

Top-bar-hive
Here is my top-bar hive with the cluster right in the middle. © Rusty Burlew.

Heat converted to visual images

So here are a few observations on my first attempts at thermal imaging. My husband helped me with this post by providing the comments in the gray boxes. He said the information comes from a Wikipedia article on thermography, the specifications of the Flir One, and his vast knowledge of engineering.

Hive-4-front
This thermal image was taken of the front of hive #4 and clearly shows the position of the cluster. The other two hives on this stand are empty. © Rusty Burlew.

Thermal imagers work by converting heat into electronic signals which can then be recorded and viewed on a video monitor. The Flir One imagers designed to work with smart phones have two lenses, one to take a normal digital photograph of the scene, and one to sense heat gradients. In the final photo, the heat gradient is overlaid on the photograph so you can see where the heat is coming from.

Hive-4-back
This is the back of hive #4. Because the cluster is in the front, the wooden in the back is less warm. © Rusty Burlew.

Thermal imagers do not “see” inside the hive, but rather they detect heat coming from the hive. For example, the two photos shown here were taken of the same hive, one from the front and one from the back. From the front, the cluster is clearly visible, but from the back it is not. This tells me that the cluster is very close to the front of the hive because the wood in the front is warm.

Since the thermal imager detects heat, it does not show the cluster from the back of the hive because the wood back there is not nearly as warm. From the bees’ point of view, it makes sense that this cluster is in the front of the hive because that is the side facing the sun. The bees take advantage of existing heat whenever they can.

Rich says: In a nutshell, what the beekeeper sees is the heating of the wooden hive caused by radiant and convective heat transfer from the cluster to the walls of the hive. In turn, the emissivity of the wood is detected by the camera and converted to visible light, allowing the beekeeper to inspect the hive non-invasively.

A single image, taken from one side of the hive can reveal a source of heat, which is good evidence that there is a colony present in the hive. This single image obviously reveals the height of the colony. This alone is useful because a colony that is very high in the hive may be out of food and need supplementary feed.

An image from two adjacent sides, or even three or four sides, will help triangulate the location of the colony in longitude and latitude. The colony not appearing on one or more of the sides is likely to indicate the colony is distal from the image side, or that a draft within the hive is cooling the inner surface on that side. It is very unlikely that this result is indicative of a camera failure.

Features included in the Flir One

These little cameras are loaded with features. You can choose different color palettes to view the photos either before or after you take the picture. Different palettes show the heat gradients in different ways. You can easily take the photos and then scroll through the pallets to find the one that tells you the most.

The Flir One offers a choice of color palettes. Generally, the user should choose one that gives detail on the temperature gradient. For example, a large white mass provides less information on the cluster of bees than an image with white in the center and multiple colored rings. The finer gradient image helps in deducing where the center of the cluster is.

You can also read the temperature in degrees C or F, or turn that feature off so you don’t see it in the photo. With a single swipe of the screen, you can remove the thermal image overlay and see the plain digital photo underneath which is helpful to better see where things are.

Thermal images around the house

As soon as Rich saw the thermal images, he (mis)appropriated my phone to take photos of windows, doors, and roof penetrations looking for heat leaks. Plus he discovered that the dog’s nose is really warm, white hot actually. Just saying.

The Flir One is useful for finding thermal leaks on houses. This is not a frequent use, but repairing these leaks, which can occur when water is entering too, saves energy, improves comfort for occupants, and prevents damage from becoming even more costly to repair as the problem lingers undetected.

Pump-house-hive
This hive is behind our pump house. You can see the cluster and also some heat leaking out of the upper entrance. The pump house has a heater inside to keep it from freezing, and you can see heat leaking out around the foundation.

The range of temperatures for thermographic images is -50°C to over 2000°C. The Flir One IR cameras operate in a much narrower range, with a “scene” temperature of 32°F to 212°F, perfect for beekeepers checking hives and homeowners looking for thermal leaks at their home. The Flir One may not be a good choice for a technician analyzing the performance of a boiler producing super-heated steam because its range of performance is too low. Infrared film is sensitive in the range of 250°C to 500°C, also of little use to beekeepers.

Worth the price if you can save some bees

Hive-3
I was amazed to see the bees in hive #3 were in the candy board or just below it. The upper entrance you see is between the upper brood box and the candy board feeder. © Rusty Burlew.

Although I was hesitant to plop down money for the imager, I believe it may have already saved two hives. All my hives have candy boards in place, and I had no intention of checking on them further until the first of the year. But much to my amazement, the images show that two of my colonies have already moved up into the candy boards. I knew they were short of food going into fall, but this was unexpected. Time to buy more sugar.

I was first convinced of the value of these cameras when I saw the images taken by Maine beekeeper, Judith Stanton. She saw a mouse nest in her hive and was able to take it out before it did serious damage. Awesome. The take-home message here is important: if you see something weird in your photo, don’t blame the camera. Instead, open that hive the first chance you get.

Open your hive, share your finds

If you are confused by the results of a thermographic image, you should consider opening the hive to learn what is happening. Then you can inform everyone, through a comment, of what the anomalous observation was and what you found in the hive so that we all learn more.

I’m in the process of setting up a gallery of hive thermal images. If you want to include your photos, you can email them to me (rusty@honeybeesuite.com). Be sure to say where in the world you are.

Rusty
Honey Bee Suite

Flir One for iOS and Android are available on Amazon.

Note: This post contains affiliate links.

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Comments

Paul Packbier
Reply

Isn’t it great to have an engineer around the house?! My wife is so lucky …

“Flir One for iPod and Android …” should be … “for iOS and Android” to compare apples to apples.

Rusty
Reply

Paul,

How embarrassing. Thanks. I fixed it.

erika klein
Reply

Will it work if the hive is wrapped in tar paper for the winter?

Rusty
Reply

Erika,

I’m guessing, but I think the air layer between the hive and the tar paper would make it not work very well. I can try it and give you a report.

Vas
Reply

Very nice!

Tony Puddicombe
Reply

I am receiving 2 emails for each posting. You must have my email listed twice in your database. Please remove one.

Really enjoy your posts as I live in Vancouver BC and I can relate to the information. I belong to the Richmond Beekeeping club which has about 120 members now. A few months ago we hosted our annual provincial conference. It was a 3-day affair with many speakers and loads of volunteers to run it. Do you ever come up to Canada to give talks?

Rusty
Reply

Tony,

I will delete if you wish, but your e-mail only comes up once in my database.

Matthew Harris
Reply

I really want one of these, but I have poly hives and suspect they wouldn’t work through all that insulating poly …. if anyone has a FLIR image of a poly hive I would be very grateful for it posted here!

Rusty
Reply

Matthew,

The consensus seems to be that they won’t work because the heat is trapped inside instead of passing to the outside.

Rich Morris
Reply

Nice post Rusty. I love it that people are interested in figuring out how their bees work.
We have had temperatures dive this week (-5F right now) and I’m happy that I wrapped my hive. My thermal camera doesn’t see much through the insulated cover… just the way I want it. Keep that heat inside!

Cheers.

Rusty
Reply

Rich,

Merry Christmas to you, your family, and the folks at Broodminder!

Loralei
Reply

Thanks for the photos, Rusty – I’ve been seating to look at possibly getting an attachment for my phone. In my first year newbee excitement, though, I couldn’t resist using my stethoscope to listen to my colony. The sounds inside were simply amazing – the low hum of the bees, with occasional higher pitched buzzing by one bee, signifying only something that they would know.

After that experience, the yearning for a FLIR only grew, & now the knowledge that this accessory may have saved 2 of your hives? It’s definitely on my wish list now! Cheers to you, for being such a wonderful resource for information – and Merry Christmas to you as well!

Rusty
Reply

Loralei,

Merry Christmas to you too!

John Zone 5
Reply

Great pics. I too am interested in getting a Flir but was wondering if it would work through a Bee Cozy hive wrap. 1 degree outside today. Do beekeepers in the South lose any hives to weather?

Rusty
Reply

John,

I imagine they lose them to weather, just not cold weather. More like tornadoes, hurricanes, and floods. I think the bee cozy would interfere with the heat readings, due to the insulating layer of air between hive and cozy.

Glen Buschmann
Reply

With just a bit of tinkering you might be able to set the color palette so that the nose of your dog glows red for the holidays. I suppose you might not be able to get the dog to sign a release waver, but … . Ho Ho Ho.

Thinking down the road … is there enough focus / definition to pick up finer detail, like the body heat of a bumble sleeping in a crocus, or a hummingbird in night torpor, (or my spouses popsicle toes)?

Holiday Best, Glen B

Rusty
Reply

Glen,

I’ve been wondering the same thing. Maybe I could detect those early spring bumble bee nests.

Eddy Radar
Reply

Not to mention for hot flashes. Fun to be had by all! Actually, I can find vermin in the garage, and count the chickens in the coops, to see who is sleeping where!

Rusty
Reply

Eddy,

I tried to find mouse nests in the wood pile, but no luck so far.

Renaldo
Reply

From our house to yours, we wish you a good Christmas. We add your family and your blog to our “thanks” list. Thank you.

The Raymond family from Roseburg.

Rusty
Reply

Renaldo,

Thank you so much and Merry Christmas to you and yours as well!

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