Aliens invade the Bird Box

While visiting my Dad I thought I would check the old nest box in the garden. It was full of lovely Bumblebees. By balancing on a rickety stool and holding on to the water butt downpipe I managed to reach one hand up to the entrance and get a few 'quick' shots.
When I got home I went online to identify them.

Tree bumblebee, Bombus hypnorum

Very distinctive colouration, brown thorax, black abdomen and white tail.
Colonised the UK only in 2001.
Common in the south of England , spreading north. Prefers to nest in holes in trees OR bird boxes.