When I was at Thornton Creek Park the other day, I stumbled (almost literally) across a cold bumble bee queen, just emerged from hibernation. That's my presumption. When I first saw her, she was moving very slowly, but gradually warmed up and moved faster. I was so excited I immediately got down onto the ground and started snapping away like mad, just having fun watching her through the viewfinder. As she revived, she moved faster, groomed herself, hopped from the ground to a grass blade, then disappeared.
Only one bumblebee survives the winter from any given nest. That survivor has to be big enough to not only survive hibernation, but raising the first generation of workers when there isn't much in bloom yet.
I felt rarely privileged to be in the right place and the right time. I was so excited and happy, in fact, that very few of the pictures turned out. Hah! Herewith, five not very good photos of a bumble bee queen.