A conversation with a fellow bee fan on Twitter led us to Ainsdale Beach on the hot and sunny Easter weekend. Ainsdale Beach is part of the Sefton Dunes NNR (National Nature Reserve) and is designated as a Special Area of Conservation – not just due to the wildlife found there but also due to the fact that is is part of the UK’s fastest-eroding section of coast.
It is a shifting dune system and therefore needs to be carefully managed as the form and shape of the dunes constantly changes. There are large areas of the dune system which flood seasonally and provide a habitat for many coastal species. It is host to a number of uncommon and rare species such as Natterjack Toads and Sand Lizards as well as the smaller creatures that I had come to see.
I was looking for the Vernal (or Spring) Colletes, a fairly uncommon bee that is only found in the UK at a few sites on the North West Coast and North Wales.
The Vernal Colletes nests within the sand dunes, using the hollowed out surfaces on the side of the slacks caused by erosion. South facing slopes are preferred for maximum sun exposure to keep the nesting area as warm as possible.
The bees form large nesting aggregationss, containing thousands of nest tunnels and bees. Although Vernal Colletes are a species of Solitary Bee, they could perhaps be described as ‘Semi-Social’ as although they nest individually the tunnels are formed in close proximity to others.
As we approached the nesting area the hum caused by the buzzing of flying bees was incredible. Hundreds of males were flying just above ground level in search of females. Occasionally one would dive-bomb another male in a case of mistaken identity, at which point a small scuffle would ensue until the mistake was realised!
The females mostly hid within their nest tunnels, waiting until the coast seemed clear before emerging. I spotted a few peering out, the slightest movement meant that they bobbed straight back down again so they were quite a challenge to photograph!
I staked out one nest tunnel for a while, and only once the female within was happy that I was not a male bee did she finally emerge!
Any female spotted by males out in the open was quickly mobbed, though we did manage to spot a brave few digging new nest tunnels.
There was only a small population of Vernal Colletes at this site a generation ago, but a few changes to the management of the dunes has meant that the population has increased dramatically over the past few years. Parts of the dune system have been fenced off to protect the Natterjack Toad breeding pools, which means that Vernal Colletes nesting on the steep poolsides were protected from disturbance and damage caused by footfall, which they are particularly susceptible to. Secondly, Salix repens (or Creeping Willow) which is the Vernal Colletes exclusive food source was encouraged which in turn has meant a larger population of bees is able to be supported.
After a couple of hours taking pictures it was time to head for home. We walked back to the car park through the dune system, seeing many more nesting aggregations en route. We also spotted several of these pretty Northern Dune Tiger Beetles scurrying through the sand.
It was only when we reached the very top of the dunes and were immediately sand blasted by the wind that I realised how sheltered the dune slacks are – where we’d been had been hot and completely still – and so why they make such a great habitat for so many creatures.