i always look at/consider:
mite problem/mite associated viruses
queens
my neglect
environmental
combination of one or all of the above.
strongest hives typically succumb to mites or mite related viruses or in winter, cold starvation, loss of the queen.
losing strong hives really kicks my butt. losing any hive i don't like. i haven't had any losses for the past few years.
sometimes i find things with no answers. i have kept 3 deeps and followed doc spivaks u of m for keeping bees in northern climates. i have tried all sorts of different bee races. i settled on russkies.
i requeen when i think necessary, utilize swarm cells and/or let the bees requeen themselves.
i treat for mites when necessary. i didn't like the 3 deep thing and went back to 2 deeps.
i may be neglectful sometimes but i do pay attention to weather, what's blooming and what's not, pollen and nectar coming in and how my queens are doing, and mite loads. i equallize hives, and supplement for what looks to be needed.
i had a really strong hive that did puzzle me this year. (russian queen)
snarky as all get out and crazy for the past 3 years.
same queen, i marked her (i don't usually mark queens) great layer, great honey making hive. treated for mites.
hive busting at the seams going into winter again this year. almost added a third deep.
deep honey frames full, kept watching to put sugar bricks on.
one week shes there, open up the next week to add a shim and sugar bricks, not one bee to be found in the hive and it was october.
absconded.
not only this one but three others. open the hive, not one bee or dead bee in the hive.
i did everything right, or so i think.
so here's my synopsis.......we have two gas pipelines running through our property, and underneath a river that runs through our property. one of the gas pipelines was exposed this past spring during a flood. propane.
the pipeline had to be replaced and redrilled underneath the river bed. it was an incredible experience to watch the process of how this is done.
the pipeline company had to mow down about 3 -4 acres or more of fall and late fall blooms that my bees would typically use for winter stores within the easement and more outside the easement (yes they paid) to replace the pipeline.
goldenrod, milkweed, asters etc...........
i watched when they mowed these floral sources down. thousands of bees in the air, and thousands of bees caught and lying dead.
the pipelines i guess are about 300 yards from where my hives sit.
we had noisy equipment, trucks, and lights running 24-7 for almost 2 1/2 months.
i kept checking my hives because of the loss of the foraging.
dunno, but i think lost my hives to environmental reasons.
"At the end of the winter, I assess my remaining hives. I will try to avoid breeding from a hive that needed feeding or consumed a lot of stores."barbarian, there are many factors for why bees need feed or consuming stores.
i will feed my bees when there is no incoming pollen/nectar sources. seems the past few years, late summers will create a feeding situation with warmer weather. not sure i wouldn't breed from these hives with great queens, because i have.........just saying,
we are not always dealt the best and do our best when it comes to keeping what we have going.