This photo shows how bumble bees are covered in hairs. This helps keep them warm and also helps them collect pollen when foraging on flowers. The pollen collects on the hairs and then the bees rub the pollen off with their legs collecting it in pollen baskets on their backlegs. We  have found B. sitkensis nesting in grass clipping piles on the ground, in an old mouse nest under some boards, and one nest from a well house ceiling insulation. Most of the B. sitkensis nests we have removed have been small  with 15-25 workers and  producing 10-20 queens.

This is a male B.sitkensis foraging.

This nest is B. Mixtus. Common to the area having small nests with 20-40 workers and producing an average of 15-25 queens. They are often seen foraging. Most of the pupa cells in this photo are queen pupa.This nest has about 50 queen pupa, at least 8 queen larva, and at least 6 empty queen pupa cells that queens have allready hatched from.

This species B. nevadensis we have only seen a couple of times here. They were observed foraging in late June.