Welcome to the forum.
You bee is a Red tailed Bumblebee (Bombus lapidarius)
They usually nest underground but will use other nesting sites, such as bird boxes.
I have had them nesting in a bird box before.
They can form quite large nests, maybe up to 200/300 individuals in the right conditions.
Enjoy their coming and goings, and if the nest is successful you should see some large young queens.
Nice pic. I agree with Kevin - your bumble is a Bombus lapidarius. In the past, I too have had them use a bird box in my garden, but this year their numbers have been low and their favourite Campanulas are in flower - waiting - but no B. laps! Lucky you!