One of the species we wanted to see if we could whilst on Orkney was the Great Yellow Bumblebee (Bombus distinguendus). It is a species in decline in northern Europe and is one of the UK’s rarest bees. Although it can turn up throughout the British Isles, the Orkneys and the Western Isles are the best chance to see this large and distinctive bee.
Of course, every site on Orkney with an interpretation board suggests you might see the Large Yellow here – along with hen harriers, short-eared owls, otters and Elvis. Nevertheless we kept an eye open in all the likely habitats.
Eventually on another walk in another area where this elusive bee might be found Jan decided to examine the clearly non-native, but extremely large, fuscia bush. Just on the basis that all bees like fuscias. I don’t know if that’s true but certainly seemed plausible, and indeed there we found our first two or three GYBs. We even managed to get a few snaps, but these were mainly of bees’ bums hanging out of the flower bells.
Surprisingly well named, this bee is large and yellow, and deserves close inspection to see the subtle yellow banding across much of its body.
We saw a few more away from the fuscia but in high winds – to us, not to Orkney – the bees were a bit more elusive. No sooner did they leave one thistle flower than they were 20 metres away clinging on to the next. Finally we find one, exhausted from its exertions, perched on a reasonably sheltered leaf where we could get some better views, although pin-sharp photographs were still tricky in the wind.
Having got our eye in for this bee we have now seen a few more, and hopefully with better weather due we may get a chance for some better pictures in the next day or two. We’ll let you know.
In the meantime here is an extract from the Natural History Museum’s conservation notes for this species.
Conservation status Bombus distinguendus is a flagship species for the Bumblebee Conservation Trust in Britain and a UK Biodiversity Action Plan species. Bombus distinguendus is classified as Nationally Scarce. Threats Multiple factors threaten B. distinguendus, chief among which is often habitat removal, particularly with the reduction of red clover cultivation since 1940 due to changes in farming practices. The main driver of decline is believed to be a reduction in the density of food plants with deep flowers over large areas of suitable grassland habitat (Williams & Osborne, 2009). Continuous availability of suitable habitat within and across years is important, because the bees may not be good dispersers, and are not known to have colonised any new areas across barriers of unsuitable habitat. Climate change is unlikely to have been the main driver of decline in the past. Although there is an interaction between the effect of food-plant availability and climatic specialisation and a future impact is possible (Williams et al., 2007). The impact of pesticides is unknown.