Tree Bumblebees

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 On my walk along the River Eden on 2nd March I was surprised to see my first bumblebee of the season. Overnight temperatures have been well below freezing so I wasn't expecting to see them. Even more of a surprise was the fact that the species I saw was a tree bumblebee although I now read that they are among the first to emerge in Spring when the females patrol looking for a nest site.

I took this picture with my phone but you can still clearly see that the back of the bee is covered with pollen, probably from the lesser celandines that are now in flower. Identification is pretty straightforward as this is the only bumblebee that looks as if it is wearing a brown rucksack.
These bees are now widespread in the UK despite only having arrived here from Continental Europe in 2001. The bees have been spreading North ever since. I was first aware of them here about 5 years ago when they took over one of my bird boxes to nest in. In 2017 the bees reached Ireland.
In nature the bees nest in holes in trees, but their spread has been much helped by their willingness to nest in bird boxes and roof spaces. Tree Bumblebees have some characteristics which sometimes cause alarm to the public. The nest quite high up and are very obvious. Nests are often noisy and this bee noise can cause disquiet if it is coming from a roof space. The bees have a "surveillance flight" behaviour where a "cloud" of bees might hover outside the nest hole which draws attention to them. Finally the bees react to vibrations if anyone tries to move or disturbb the nest and might sting people. Left to their own devices they are harmless!

Diary Notes
I made the most of the good weather yesterday to do a walk taking in farmland, sunken pathways, the top of Smardale Fell, and the banks of Scandal Beck. A route and some pictures are below. I was delighted to spot my first primrose of the season by the side of the lane. At the top of Smardale Fell where we stopped for lunch I heard skylarks singing for the first time this year. Several buzzards, a heron, and a distant view of a hare. Local social media has images of hares "boxing" an event that I have yet to witness but I am keeping my eyes open. Overnight cameras revealed a fox drinking at the pond.








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