From the BWARS Forum:
This morning (Sunday 17 December 2006) we visited the Valley Gardens at
Windsor Great Park. There we saw 5 Bombus Pratorum workers
simultaneously collecting pollen and nectar from rhododendron flowers.
The bumblebees were very easy to observe as the Rhododendron
pachysanthum was on the edge of the path. The workers had one yellow
band on the thorax but the band on the abdomen was virtually absent.
Each had the typical orange tip to the abdomen. They each had the
typical rounded "dumpy" shape of B.pratorum. They were all small and
one was very small. Four out of the five were collecting pollen as
well as nectar. This particular rhododendron has been flowering for
the last month. It has small cup shaped white flowers pointing upwards
and the workers were climbing down into the flowers. The rhododendron
is growing on a warm south facing bank and was in full sunshine. The
air temperature was only about 6C. The exact location is the south side
of High Flyers Hill SU969694

Later on we saw one more Bombus pratorum worker on winter heather in
the Heather Gardens. This was also collecting pollen and nectar. The
bed of Erica x darleyensis "Karmer's Rote" was in full sunshine. About
half an hour later as we returned we saw one more B.pratorum worker in
the same location (or the same worker again). The location is SU971697
about 400 metres from the first site.

During this walk we also saw 4 queen Bombus terrestris on mahonias and
2 queens and 2 worker B.terrestris on winter heathers.

We also saw about 12 worker wasps on the mahonias, and 3 red admiral
butterflies.

Bumblebees, wasps and butterflies were only seen on flowers in full
winter sunshine.

Steve Farmer
 Sunday 17 December 2006

Stuart Roberts responded:
These are pretty remarkable observations of B. pratorum at this time of year! Clearly an active nest.
I do know that our French colleagues were observing B. pratorum in late Jan this year in the Bordeaux area.

2. Bombus pratorum workers in Windsor Great Park December 2007.

(This is based on the BWARS Forum posting #2549 11 Dec 2007 and #2580 30 Dec 2007).Steve Farmer 

This is a brief summary of some recent observations during November and December 2007 at Windsor Great Park, in the Valley Gardens and Heather Gardens (SU96).  There have only been 2 air frosts in this area during the early winter and many winter flowering shrubs are already in bloom. 

The most interesting observations have been of Bombus pratorum. One Bombus pratorum queen was seen on 25 Nov on Rhododendron pachysanthum collecting nectar.  On 11 Dec there were 1 queen (nectar) and 2 workers (pollen and nectar) on the same rhododendron and one Queen (pollen and nectar) on Prunus subhirtella and 1 worker (nectar) on Mahonia. 

On 30 Dec I was able to confirm that there was certainly a Bombus pratorum nest in the Valley Gardens at Windsor Great Park for the second winter running. There were just two B.pratorum workers on Rhododendron pachysanthum at midday in bright sunshine. This rhododendron comes into flower very early and has a long winter season. The position is very sheltered on a south facing bank under scattered mature Scots pines. The earlier flowers have been damaged by recent hard frosts(minima down to -6C locally) but more fresh flowers have opened. The flowers are cup shaped facing upwards and the B.pratorum workers have to climb down into the middle. They are very easy to observe on the edge of a path and there is no problem about identification. 

There were no further sightings of Bombus pratorum workers during three subsequent visits to the Valley Gardens during January 2008 

 In the BWARS Newsletter Spring 2007 pp.11-12  I reported that last winter B.pratorum workers from an active Bombus pratorum nest were seen between 17 Dec 2006 and 15 Jan 2007.  It appears that another Bombus pratorum nest was established this winter in the same location but probably failed soon after New Year.