Bumbling Along

A couple of days ago we went walking in a local den which is a strip of woodland with a steam running through. At this time of the year its usually hard to see much and so it proved. 
We retreated to the upper slopes where it was quiet of people although a bit windy. There, we found a couple of bumble bees feeding. I had an inkling that I hadn't seen this pattern before so I took a couple of pictures but the wind made it difficult.
Back home I found another on the pavement in front of the house (pictured). Its a Tree Bumblebee. 
Tree Bumblebees were first discovered in Britain in 2001. They have been steadily moving northwards. They are aided by a liking for nesting in bird boxes so humans have been helping them along if inadvertently. It was satisfying to find a new species literally on the doorstep.