I prepped my honey bees for winter, but they died. What happened?

Disclaimer: It is sometimes difficult to piece together a post-mortem of your hive. The best way to get your bees to overwinter is to plan ahead. It is disheartening when hives die, but you are planning ahead *RIGHT NOW* to increase your survivorship by learning more.

A few questions:

  1. How heavy were your brood boxes going into winter? Did the bees have enough resources to make it through winter? In Minnesota, we build up our colonies into 3 deeps and leave 75-100 lbs. of honey for the bees to make it through winter and 3-5 frames of pollen to give the bees enough protein to begin raising brood in February. See: Link to wrapping poster  There are different overwintering needs for honey bees in different areas. Check with your local beekeepers association or find a mentor to help you.

>Evidence of a starved hive: (cluster of bees on empty frames with dead bees filling the cells):

Evidence of starvation, dead cluster of honey bees. Photo Credit: Chris Kulhanek 2015

Evidence of starvation, dead cluster of honey bees. Photo Credit: Chris Kulhanek

Starved Cluster of honey bees, some inside cells Photo Credit: Chris Kulhanek 2015

Starved Cluster of honey bees, some inside cells. Photo Credit: Chris Kulhanek 2015

Evidence of starvation: Honey bees in empty cells. Photo credit: Chris Kulhanek 2015

Evidence of starvation: Honey bees in empty cells. Photo credit: Chris Kulhanek 2015

  1. Did you measure and keep notes on the bees’ varroa mite numbers throughout the season? In particular, what were your mite numbers going into winter? If they were high (as determined by your local beekeeping association), did you do something about it? (treat with a miticide/acaracide, remove capped drone comb, brood break, etc.)? Did you treat soon enough in the season so the treatment or intervention had time to work according to the label, or to do some good?

After you intervened, did you check the mite levels to see if the mite numbers went down? If you don’t check AFTER the treatment or intervention, how will you know if it worked? There are a few indications that your hives had high mite levels: Deformed Wing Virus (DWV), Parasitic Mite Syndrome (PMS), and small bees.  See here for more info and photos.

If you didn’t check your mite levels, don’t fret. Start this season. Learn the good, bad, and the ugly about your hives so you can make informed decisions about what might (and might not) be impacting your hives.

Secondary things that can occur in your hive after your bees are dead or dying: (robbed colony-ragged comb, mice damage, mold, crystallized nectar).

>Robbed colony (ragged empty comb, a lot of detritus on the bottom board, maybe dead bees, maybe not):

Robbed out honey bee comb: note the ragged appearance of the comb, unlike what a mouse or other pest could do.  Photo credit: Chris Kulhanek

Robbed out honey bee comb: note the ragged appearance of the comb, and no webbing, unlike what a mouse or other pest could do. Photo credit: Chris Kulhanek

>Mice damaged colony (turds, urine smell, chewed frames (wood and wax), maybe nest material in the bottom of the box:

Mouse chewed wax.  Photo credit: Chris Kulhanek 2015

Mouse chewed wax, down to the foundation. Photo credit: Chris Kulhanek

>Moldy bees or cells:

Moldy bees, after winter. Photo credit: Chris Kulhanek 2015

Moldy bees, after winter. Gently scrape these off and new bees will be able to reuse the comb. Photo credit: Chris Kulhanek

Mold on Frames after winter Photo credit: Chris Kulhanek 2015

Mold on Frames after winter. Photo credit: Chris Kulhanek

>Crystallized nectar in cells:

Photo credit: Chris Kulhanek

Crystallized nectar in overwintered honey bee frame.
Photo credit: Chris Kulhanek

***In all of the above photos, the comb is still usable and bees will clean out the comb and use it.

Good news! You get to start over this year. Make plans to winter your colonies now. Think about how you are going to manage them so they have few mites, enough bees, and lots of honey for overwintering.  If you’ve successfully overwintered a hive, consider re-queening after 2-3 years to keep the hive as strong as possible.

The more information we have, the better answers we are going to get. Check out the preview of the Colony Loss Survey here and please consider participating. Click here to get on our email list and participate in the survey.

The survey goes live April 1st!








Written By: Chris Kulhanek

Chris Kulhanek has written 3 post in this blog.

Chris has been keeping bees for 5 years and has worked for the University of Minnesota Bee Lab for the last three bee seasons. She assisted in fieldwork with Bee Informed Partnership for the last two years. She has a Bachelor of Science in Biology, with a Chemistry minor, and a Masters of Science in Entomology. She particularly enjoys sharing her adoration for insects with others and is proud she has been a "weird bug girl" for more than 20 years.


14 Responses to “I prepped my honey bees for winter, but they died. What happened?”

  1. george ruble

    Last year i had 10 lost one. Expanded to 28, sold 9 nukes. Went into the winter with 15 lost one. I place a ceder chip filled winter pack with Popsicle sticks for ventilation. will post complete instructions if anyone wants. email georub@frontier.com

  2. Jeannie Smith

    I’ve been using cedar filled moisture quilts but then realized that cedar is toxic or repellant to insects (as in cedar closets etc) so I switched to regular pine chips. Prefer the cedar if not bad Foretees. Any thoughts?


    my problem is that I am NEGLIGENT!! Last summer I did not take any honey off of the hives because two were started from new Nuc’s and one was a captured swarm. I mistook the bees
    clustering outside of the hive in hot weather as their beginning to swarm so I THREW new layers onto all of my hives. Each hive had LOTS of honey going into winter but the distribution was not correct. 2 of the 3 hives starved due to my negligence. The hives that died could not get to the honey.(plus there was moisture in the hives) Was hoping to get three splits this summer. MAYBE WE SHOULD HAVE A TEST FOR BEGINNING BEEKEEPERS TO MAKE SURE THAT WE KNOW WHAT WE ARE DOING. 🙂 The ventilation was good but the snow depth was up to the entrances and the temps down to zero or below.

  4. Megan

    We just checked on our 2 hives today. All the bees were dead in both hives. There was still plenty of capped honey & pollen in the frames. We even had candy board supers on each hive. There’s no evidence of disease, pest, or rodent activity. This was our first winter & we prepped in every way we read about & were told. Honestly, I’m a little heart broken & feel like it’s somehow our fault. Did we do something wrong?

  5. Melody Mitchell

    Exactly the same problem! All points towards starvation yet there was lots of capped honey left ?

  6. Dave

    I have a problem two winters in a row I have lost my bees they were Russian bees suppose to be the best in the winter. First year I lost two hives over the winter following winter I lost three hives my wife told me it is costing to much to keep replacing them which I agree. Does anyone know what I am doing wrong I don’t take any honey I even gave them extra food that was still in there. Now I have no bees would like to buy more but I think my wife is going to tell me no more I had planed on splitting them this summer to get more hives but that isn’t going to happen. Also I had two friends that got the same bees I did and they also lost theirs also could it be where we got them PLEASE SOMEONE HELP

  7. David Lauper

    For the 3rd year in a row i im having the exact same problem. Really getting tired of buying new packages every spring. I am going into winter with strong hives with plenty of food but by January there is a massive die off. I saw a program filmed in europe that showed the bee keepers buring all of there frames and strarting off new after having massive kills, they were blaming their kills on nosimia or other diseases and said the only way to prevent carry over is to start new?