Why do bees swarm when outer frames have not been drawn out?

[Bungle]

Hi,

My understanding is that a swarm comes about because of a lack of space. And yet my bees swarmed and left behind un-drawn frames?

On reflection, i noticed that all of the 'drawn' comb was full of brood, but i thought there was still enough room in the un-drawn frames (x4), and that they would build out the comb as needed.

Is it common for a swarm to happen even when the outer frames have not been drawn?

 

[GuyNir]

I believe bees don’t see undrawn foundation as usable space.

 

[Finman]

Hi,

My understanding is that a swarm comes about because of a lack of space. And yet my bees swarmed and left behind un-drawn frames?

On reflection, i noticed that all of the 'drawn' comb was full of brood, but i thought there was still enough room in the un-drawn frames (x4), and that they would build out the

 

[Finman]

Bees swarm because they have instinct to reproduce. If extra space would hinder swarming , swarm control would be easy.