There are just three bees on the Fair Isle list:
‘Shetland Bumblebee’ Bombus muscorum agricolae • a dark-bellied subspecies or possibly a colour variant of the Moss Carder Bee
Buff-tailed Bumblebee Bombus terrestris • first recorded 28 March 2012
Northern White-tailed Bumblebee Bombus magnus • several sightings in 2014
Usually the only bumblebee found on Fair Isle is the ‘Shetland Bumblebee’, although in 2012 the Buff-tailed Bumblebee appeared in reasonable numbers as part of an apparent invasion into Shetland. With no Buff-tails reported in 2013, it appeared that the invasion had petered out, but in 2014 there were several sightings of Northern White-tailed Bumblebee, a species not previously on the Fair Isle list, although they are common on mainland Shetland.
The Shetland Bumblebee can be on the wing as early as March, but the main flight season is from May to September.