I'm wondering how warm it has to be for spring activity.
Bees lose muscle flexion in the low 50s. If they are already flying when it drops they can continue. They will break cluster to fly and attack at lower temps but it is a Kamikaze mission.
I've seen my bees forage on a bright sunny day of 43 degrees.
Be Yourself, Everyone Else Is Taken!
Some of my bees were flying yesterday in a light mist at 43 degrees. I think that it depends on their perception of need, the number of bees required to keep brood warm and the quality of the source that they have found.
4 seasons 19 Hives-Camp Branch Bee Ranch. Est 2009
"I am a nobody; nobody is perfect, and therefore I am perfect."
55 degrees F.
The above temperature is written in many books.
However, wind and time of day works into the answer.
My Russians and Carniolans are the 1st to fly
One must remember that advertised temps (local TV station) are taken in the shade, a sunny day @ 43 degrees is not 43 degrees to the bees in full sun.
Red Dirt Apiaries
There was no sun in our misty showers.
On a still day
- 45 degrees for my Russians
- 55 degrees for my Italians
The ones that I was watching were NWC.
Mega bee and open feeding.
This last winter, my bees tried flying too soon. I found several frozen stiff in the snow.
I don't expect to see them flying until it's 50 F and sunny. But I have, on one occasion seen a steady stream of them bringing in something when it was 27 F, sunny and calm (a rarity in my part of the country). I thought they had lost their minds. But then they are dark Northern bred regressed bees...
The wind plays into it somewhat. I've observed my Carnies fly on a sunny day, with little wind in the low 50's (~53-55 F) .
It really depends on what you mean by forage. Does one bee every 30 sec or so constitute foraging or does it mean 5-10 per second? When I think of foraging, I think more along the lines of the latter ratio. Therefore, with this criteria, I would say that the temp would have to be about 55-60 degrees Fahrenheit to observe "foraging."
27 fahrenheit and also bringing something in.
That will take the cake no one is going to try to beat that.
What I have seen is that Italians are pretty religious about the 55o thing, and Carniolans will start work about 3o less than that which can be a significant amount of time on a slowly warming morning.