Last year Jess Barrett, RSPB Scotland's Country Communications Manager took some time away from her desk job and set off on an adventure to Islay, in search of some very elusive little bees. Here she tells us all about it.
If I asked you to think of a bee, would one that burrows into coastal sand dunes spring to mind? It certainly wouldn’t have for me until a few years ago when I learnt about the Northern Colletes from a colleague. Little did I know then, but this wee bee would go on to have a big impact on my life.
Northern Colletes, also known by its scientific name of Colletes floralis, is one of around 75 species of bee found in Scotland and is a solitary mining bee. This means that it digs its nest in the ground, and nests alone.
The species is very rare. Around half of the world’s population is in the UK and Ireland, and in Scotland they have only been recorded in a few places on the west coast and some islands. They are found in coastal sand dunes, and machair, itself a very rare habitat.
The type of coastal sand dune habitat the Northern Colletes burrows in
The adult bees a quite wee, about 1cm in length, and they are only active between mid-June and late August. They nest in aggregations which means what might appear as a colony are actually lots of separate burrows – each one home to a single bee – all close together.
Taking all of this into account it is not a bee that you will easily come across and yet in summer 2022 I set off to Islay for four weeks to search the island for them!
My time away was for my sabbatical and I had certainly set myself a challenge. My day-to-day work in the RSPB Scotland communications team is usually office based and I hadn’t done any kind of survey work before. A colleague had taken me to our Loch Leven nature reserve to do some bee survey training which meant I at least knew the practicalities of how to look for them and how to record the information about them. It was just now a case of finding them …
Islay had been surveyed back in 2006 to confirm whether or not Northern Colletes were present there and they had been found in a number of places on the island. Armed with this report my task was to revisit all these places in it to see if Northern Colletes were still present and to check out other potential sites for them.
I arrived in mid-June when the adult bees usually begin to emerge. However, it had been a cold spring and the temperatures were below average for that time of year. For the first week I visited all the places the bees had been recorded along with the possible new sites identified by the RSPB Scotland Islay team as having ideal habitat for them.
This meant travelling all over the island, and some very long walks to reach the coastal sand dunes, but I didn’t see a single Northern Colletes! And while I was certainly enjoying the work and some of the other fantastic Islay wildlife along the way such as the eerie mournful moans of seals on loch sandbars and high-pitched calls of Oystercatchers overhead, I did worry that just maybe the bees were there and I was missing them …
That all changed in the second week as the weather got warmer. At Sanaigmore, a place where in 2006 burrows had been recorded but no Northern Colletes seen, I finally spotted one! It was resting on the sand so easy for me to catch in a collecting pot to have a closer look and confirm it was a Northern Colletes by sending a photo to a colleague. To say I was happy is an understatement! I had finally found one and from then on for the next three weeks it was bees galore!
The first Northern Colletes I saw!
Once I had an eye for them, I really tuned in to what to look for – small dots just a few millimetres wide usually on south facing sand dunes, in between the plants, were the bees’ burrows. Sometimes, I would find these but no bees. If I did see a bee, I would then have a look around for others, recording how many I saw, noting down the size of are they were spread across, the number of burrows I could see, and how the bees were behaving.
Loads of Northern Colletes
I got really tuned into how the time of day and weather impacted them. In the morning they tended to be a bit slower and sluggish but once warmed up in early afternoon would be buzzing and hovering around. I could feel the heat radiating off the sand in the afternoons as I got close up to count the burrows. Any time the sun disappeared behind a cloud the bees would cease their flying about and stay on the sand or curled up in flowers. It was incredible to find huge numbers of them in some places, over 100 bees spread across the terraced sand dunes towering above me, and other times just one or two. I was really chuffed to find them in some places they hadn’t been seen before.
Northern Colletes in a flower. I saw a lot like this.
And I made another very special recording while looking for Northern Colletes. My colleagues had asked me to keep an eye out for the grubs of Short-necked Oil Beetles, a very rare beetle which until 2008 was thought to be extinct in the UK. The grubs are often found close to Northern Colletes burrows and are about at the time of year I was surveying.
The year before a dead adult beetle had been found by Buglife on Islay, the first recording of the species there, but no alive adults or grubs had ever been seen there. It seemed a bit of a long shot as the grubs hide away in yellow flowers, but I was making sure to check them just in case. What no one was expecting, especially me, was that I would find an alive adult. And yet that’s just what happened!
Scrambling up a steep sand dune in Killinallan one afternoon a shiny blue black coloured beetle about 2cm long curled up on a flower caught my eye. Brimming with excitement I quickly took a few photos and sent them to a colleague to confirm the ID and got a very excited message back – it was indeed Islay’s first ever recording of an alive adult! And by the time my four weeks on Islay came to an end I’d recorded two more!
Islay’s first record of an alive Short-necked Oil Beetle
My time on Islay was incredible. I loved being outdoors all day, every day, searching for these small rare insects which I became very fond of, and getting to know Islay well. Northern Colletes and Short-necked Oil Beetles are two of the 37 rare species that Species on the Edge, a National Lottery Heritage Fund supported partnership project that RSPB Scotland is involved in, is helping to improve the fortunes of. Having more records of where they are means that project knows where to target efforts.
I’m delighted that not only have my records contributed to this, but that the data has also helped guide survey work this year on them which led to more records on the island. The sense of achievement is amazing and I’m so happy to have been able to play a part in discovering more about these two species.
All images: Jess Barrett. Main image: the coastal sand dunes at Killinallan.