Friday, 24 June 2016

Can I stay in Scotland?

In an attempt to distract myself from today's headlines, here's a summary of my two week stay in the highlands, looking for the rare and elusive pine hoverfly. Sadly I wasn't able to find any pine hoverflies, I suspect the terrible weather last week may have played a part, but it was always going to be a difficult challenge, so I'm not too down-hearted. Instead of dwelling on what I didn't see, I'll focus on all the fantastic wildlife I did see - I've already mentioned such wonderful creatures as the bumblebee robberfly and the pine tree munching longhorm Rhagium inquisitor in my previous post, but there's a lot more to come.

Last Saturday the weather finally came good, just in time for a trip over to the RSPB's Crannach reserve to do a bit of surveying, alongside a lovely group of like-minded people who'd gathered for a fascinating workshop on wood ant identification. Unsurprisingly ants were high on the agenda, and we found a nice range of species, including one of the two Scottish species of wood ant, Formica lugubris, the hairy wood ant. Other insects included the luridly green sawfly Rhogogaster punctulata, and I was delighted to find one of the hoverflies I swept from the flowery tracksides turned out to be Xanthandrus comtus, a scarce species in Scotland.

Formica lugubris
A (very subtley) hairy wood ant
Undoubtedly the star of show from a purely personal point of view were the bright orange small pearl-bordered fritillaries that were fluttering over a area of boggy ground, settling only occasionally to allow a few poor photographs. In the nutrient poor environment, some plants have turned to predation, both round-leaved sundew and common butterwort were common across the site. Hopefully between all of us, we'll have added a decent amount of knowledge about the species that make this remote site their home, and help inform its management for the future.

Small Pearl-bordered Fritillary
Small Pearl-bordered Fritillary

Round-leaved Sundew
Round-leaved Sundew
After that it was back to the grind of searching for pine hoverflies, I've spent a lot of the last week staring at rowan flowers! Even if they didn't lure in the hoverfly I wanted, they did attract a lot of other interesting species. Over the course of the week I saw at least 12 species of hoverfly on the rowans, as well as several other species on other flowers nearby, and excitingly a small number of the nationally scarce (and adorable) little hoverfly Microdon analis at one of the sites. It wasn't only hoverflies though, I also spent a long time scratching my head at an oddly marked longhorn beetle, which after a bit of online discussion was agreed to be an extremely dark variant of the common northern species Judolia sexmaculata.

Sericomyia silentis
Sericomyia silentis - one of the most impressive species seen on the Rowan flowers

Microdon analis
The adorable Microdon analis

Judolia sexmaculata
A very odd looking Judolia sexmaculata
Whilst the majority of my time was spent in the quest for pine hoverflies, I did take a couple of side trips to try and see some other highland specialities, thankfully with more success! A trip on a cloudy and rainy afternoon to a site near Grantown-on-Spey produced three male and one female Aspen hoverfly, another highly endangered specialist, which is a bit easier to find than its pine compatriot. On a sunnier day I took a short detour onto the RSPB's Abernethy reserve and was rewarded with a brief sighting of the pinewood mason bee, Osmia uncinata, foraging from bird's foot trefoil, as well as the bonus of the pinewood specialist hoverfly Didea intermedia.

Aspen Hoverfly
Aspen Hoverfly - another hoverfly that doesn't look much like one

Osmia uncinata
Pine Mason Bee, Osmia uncinata

Didea intermedia
Didea intermedia
Whilst my time in Scotland hasn't always gone exactly according to plan, it's still been a fascinating couple of weeks, and if anything it's cemented my love of natural history even further. I'm looking forward to continuing to learn more and more about the fascinating wildlife of this country, and to continuing to develop a more detailed knowledge of the hoverflies that have been my focus this year.

Wednesday, 15 June 2016

Pining away in the highlands

After a very pleasant week in the lake district we've made our way north to Scotland, and specifically to Aviemore, in the heart of the highlands. For the next couple of weeks I have one over-riding target, to try and find the elusive pine hoverfly, Blera fallax. This critically endangered species has only ever been found in the ancient pine forests of northern Scotland, and at the time of writing, is only known to occur at one site. My aim for this fortnight is to firstly try and find some adults at the known site, to show that this is a plausible way of establishing the presence of the species, and then to go searching at a couple of other sites where Blera has previously been recorded to see if I can re-find it there.

All sounds very simple - except that at the time of writing this, it's currently bucketing it down with rain, and about 10 degrees outside - not good hoverfly finding weather! Hopefully the weather will improve soon to give me a fighting chance of finding Blera. We did get some reasonable weather on Monday, when a couple of staff from SNH came over to show me the sites. We didn't see any Blera (that would have been far too easy) but we did see some cracking wildlife, including a few highland specialities.

First up was a bit of a monster of a fly, and one that was very near the top of my wishlist for this trip, the bumblebee robberfly, Laphria flava. It's one of the biggest flies to be found in the UK, with the larvae feasting on longhorn beetles and the adults eating pretty much any insect unfortunate to cross their paths. This one was sitting on a stone by the path when we saw it, but then helpfully relocated to a pine stump - just like they're supposed to!

Laphria flava
The impressive robberfly Laphria flava
Deadwood is key for many of the special species, and a fallen pine tree produced the next set of goodies. First up was the fairly common and widespread ant beetle Thanasimus formicarius, which was swiftly ignored in favour of the much rarer Rhagium inquisitor. This medium sized longhorn has a subtle pattern of greys, browns and whites that help it blend into the pine trees that it relies upon. Much less well camouflaged is its larger relative Rhagium bifasciatum, which I saw at Farnham a few weeks ago, and which popped up again here.
Rhagium inquisitor
Rhagium inquisitor

Rhagium inquisitor
Inquisitor again - it was posing very nicely!

Rhagium bifasciatum
Rhagium bifasciatum
At all the sites I'm searching, there are a number of specially prepared pine stumps, which have had holes cut or drilled into them to replicate the conditions which pine hoverflies need to breed. These conditions are also to the liking of other deadwood loving hoverflies, as we proved by finding the larvae of Myathropa florea and Callicera rufa in one of the stumps. The latter is a funny looking creature, a large white maggot with two sets of miniature antlers (or eyebrows if you prefer)

Callicera rufa
Callicera rufa larva
There were a few adult hoverflies around, including another one I'd been hoping to see, the wasp mimic Chrysotoxum arcuatum, a northern and western species which doesn't occur in my home county of Bedfordshire. All in all a very successful first day in the highlands, let's hope it's not the last successful day I have!

Chrysotoxum arcuatum
Chrysotoxum arcuatum

Wednesday, 8 June 2016

Flies in the garlic

We're up in the Lake District this week, enjoying the sudden outbreak of summer after a miserable spell of weather. There hasn't been too much time for wildlife chasing, although there are few more pleasant ways of spending one's time than watching Grey Wagtails chirruping on the river's edge whilst supping a pint of Cumbria's finest ale as I did today.

From the moment that we settled on the plan off staying in the Lakes I've had my eye on one particular species that I've had on my 'to see' list for a while now, the hoverfly Portevinia maculata. It shouldn't be a tricky species to find, as it loves Ramsons - which carpet many woodlands in springtime, but unfortunately not any woodlands near home that I'm aware of. Around here every wood seems to be carpeted with them, so we set off this morning to the charmingly named Dorothy Farrar's Spring Wood in search of some garlic loving hoverflies.

The only fly in the ointment is that it's getting a little late in the year for the Ramsons, and with them the hoverflies, and after a little while in the wood I was starting to think that perhaps our hunt wasn't going to be successful. Just as I was starting to lose hope I caught sight of a small hoverflyey looking fly on a Ramson leaf and quickly brought up my camera to take some photos, and managed to take a grand total of one before the battery died - aargh! A quick faff later I had a new battery loaded, and thankfully the fly had stayed put, allowing me to get some nice shots of a female Portevinia - usually the harder sex to find. A few minutes later I added a male, with its distinctive square grey abdominal markings, to the set as one posed nicely on a sunlit patch of moss.
Portevinia maculata
Female Portevinia maculata

Portevinia maculata
Male Portevinia maculata
I think this probably counts as my first ever hoverfly twitch, but it almost certainly won't be my last, I've got a much harder target to aim for in the next couple of weeks - hopefully I'll be posting about that soon!