Looks like a wasp nest to me, Yves. They're usually round in shape with an opening at the bottom and grey in colour. They're common around here, last year they built one above our back door so we avoided it until freeze up. Nice shot btw.
Nice shot, Yves. I'm not sure if that might be a hornets nest, so good thing you could stand back and get the shot.
Thanks Jane. The word bee was a kind of general naming here. It is rather wasps than bees and hornets would be quite right..
Thank you very much Debra. I was lucky that I could take the shot right from the trail (about 20 feets away)