August 2022

Autumn bird migration picked up a little at the start of August with a returning Wheatear at Fort Hommet on 5th and a Green Sandpiper at Grand Pre plus 2 Greenshanks at Vale Pond on 8th. Other than that, the only bird of interest was actually a patch tick for me, with a Little Tern at Port Soif on 12th. This was highly unsatisfactory though since it was a brief sighting from the car as I drove past and was unable to stop (not found by me btw, I knew it was there!). Nevertheless, a new bird for the Hommet-Rousse patch list.

Green Sandpiper - Grand Pre, 8 Aug 22

Low water levels at the pond at Grand Pre

Water Fern - Grand Pre, 8 Aug 22 - the very low water levels at Grand Pre meant that I was able to explore some areas that are usually underwater - the above species was a new plant for me, not very welcome in the nature reserve.

One area of interest (if you like that kind of thing) that can be done in August is look for Yellow-legged Gulls on the beaches. The adults are pretty straight forward but the juveniles are more tricky. The main thing to remember is that these have travelled here from southern Europe and so were born a month or so earlier than the local Herring and LBB Gulls. This means that the sunny summer weather will have taken its toll on their juvenile feathers and so the brown colour is usually paler and scruffier than the local youngsters. This is a good way of picking out some probables and you can then focus on some finer points.

Looking at the bird below, you can see the paleness of the brown colour of the feathers, with narrow less-crisp pale edges. The main feathers to focus on are the tertials (the large brown feathers before and above the dark wing tips) which are usually finely edged pale with no notches, a bit of a paler smudge near the tip and obviously worn and battered, often wavy edged due to wear. Also below one on the mantle feathers has been replaced by a new grey-splodged feather - it is too early for a Herring/LBB to show this. The bill is generally dark and thick and the head is pretty whitish. These are the main features to look for in a Yellow-legged and I picked out 5 birds in just a smallish gull flock on Perelle beach on 10th August. I am no expert on immature gulls but I’m getting more knowledgeable year-on-year.

Yellow-legged Gull - Perelle, 10 Aug 22

Yellow-legged Gulls - Perelle, 10 Aug 22 - right hand bird pretty standard, left hand less obvious but probably still is one.

Yellow-legged Gull - Perelle, 10 Aug 22 - another bird, even from distance they can sometimes be quite distinct.

Seagull - Perelle, 10 Aug 22 - some birds cause confusion - this is a very dark bird but shows many features of yellow-legged, and i feel that it probably is one - also, the large gulls do hybridise sometimes so unclear birds may just have unclear genes.

I had too much happening for much moth trapping in the first half of August, the best night being 11th Aug when I had a few immigrant micros such as Cydia amplana, Onocera semirubella and Nephopterix angustella.

Something new that I did focus on was Diptera or flies (other than hoverflies which I have been looking at for a while). I have always been a little wary about delving into flies as there seemed a huge amount of species and so many different families, with so many looking more or less the same. Also I didn’t feel that I had enough books to make positive ID and I found using the fly family key a little confusing. However, when you focus and read more you soon see that they are doable, especially nowadays that you can find so many keys online which can be used. I had plenty of specimens to look at and I managed to work through them all finding a few new species for Guernsey in the process.

Flies from many different families

Locust Blowfly Stomorhina lunata - Baubigny, 5 Aug 22 - a good fly to find, this species is a southern species which parasitises Locusts in southern Europe and North Africa. It is a traditionally a very rare visitor, but appears to be expanding its range further north so may be now using other grasshopper species as hosts.

Mantis Fly Ochthera mantis - Grand Pre, 8 Aug 22 - found this crazy-legged species on the bare mud at Grand Pre - a new species for Guernsey I believe.

Aulagromyza populicola - Grand Pre, 8 Aug 22 - another new species for Guernsey, the larva mining Poplar leaves.

Sarcophaga caerulescens - Baubigny, 5 Aug 22 - some species of fly are tricky to identify without looking at the genitalia - so here is a male flesh fly’s provate parts - you’re welcome.

Close Encounters of the fly kind

July 2022

When I popped to L’Ancresse after work on 5th July to see a rare plant I was certainly not expecting to find a new moth for the British Isles*! I had noticed on the local Botanists facebook group that they had posted about the very rare Fringed Rupturewort, and where it could be found on Guernsey. I had never noticed this very inconspicuous, low-growing plant before so I thought that I’d have a quick look before heading back home. I found the plants quite easily as they were one of the few species on the edge of the golf course which hadn’t been totally scorched by the dry weather and were still quite green. After taking a few snaps on the phone, I noticed a tiny movement, which I thought was an ant carrying a bit of detritus.

When I got down low and put my glasses on I was surprised to see that it was a Coleophora case. (This genus of moths make a case out of plant materials which they carry round for protection). These are usually very plant specific and so I thought it might be very interesting due to the rarity of this plant which only grows in one place in mainland UK. Looking round the area, I noticed that there were lots and lots of these cases and the moth was clearly quite common here. I took a few photos and collected a few in a pot to look at later and headed home.

Coleophora cases on Fringed Rupturewort - L’Ancresse, 5 Jul 22

Back at home I looked through the books I had about Coleophora moths but there was nothing at all about any species which lives on Fringed Rupturewort. I put out a photo on twitter with a request for help, but there was no response at all. In the meantime, I was googling and finding it very difficult to find anything until I came across a Swedish website with photos of Coleophora cases on Smooth Rupturewort (a similar species in the same genus). This species was Coleophora scabrida and the photos of the cases was more or less identical to the specimens I had in front of me.

I took some better photos and was contacted by a micro-moth expert that I had tagged onto the twitter photo, who seemed to feel that these moth larvae were very likely to be scabrida as I suspected. I returned back to the site a week or so later and collected a few more specimens and mailed them off to him, and he was planning to send some off to the Natural History Museum for analysis. Coleophora scabrida has not been recorded in Britain before as far as I know, so this would be a new species for the Channel Islands and also the British Isles (*depending on your definition of what that is!).

Fringed Rupturewort is so rare in the UK that it is not a surprise it has not been found on that plant, but Smooth Rupturewort is more widespread and one might have thought it would have been found on that species if it lived in the UK. There are many species that live in the Channel Islands but not the UK, but I wonder if this is a new arrival, or if it has been here a long time undetected. This record is not fully confirmed yet and so this may all be premature, but the likelihood is pretty high. We shall wait and see.

Coleophora scabrida - L’Ancresse, 5 Jul 22

Coleophora scabrida - L’Ancresse, 5 Jul 22 - a random photo of the plant showing the density of the cases present.

As well as the exciting discovery above, July 2022 was a superb month for moths overall, probably mainly due to the ridiculously high temperatures during the month. There were a few days which reached the late 30s degrees and so the nights were so warm. The first two weekends were quite average with Splendid Brocade being the best moth in that time. On 11th July, it was my annual “bring-the-trap-to-work” day to show the year 7s and, as usual, it coincided with a good catch, the kind of catch where I’d much prefer to go through it in detail at home rather than surrounded by 12 year-olds in the school car park.

There were three new species for the garden inside the trap which I managed to pot up before they were scared away by children. There was a wave which looked slightly different - a bit creamy with buff cross-lines - which I eventually worked out was Lesser Cream Wave, very rare in Guernsey. Also, there was the “pyralid” moth Hypsopygia glaucinalis which I have only seen once before, at someone else’s trap here in Guernsey many years ago - probably a migrant here. The third was Stathmopoda pedella which I recognised straight away because the first for Guernsey was posted up just a few days before. Three new garden moths in one catch - can’t remember when that happened last.

Lesser Cream Wave - garden, 11 Jul 22

H glaucinalis - garden, 11 Jul 22

Stathmopoda pedella - garden, 11 Jul 22

As it was so good the previous night, and because I had a late start due to a school trip to Herm, I put out the trap again mid-week on 12th July, and I was pleased that I did. Wax Moth and Corn-borer were joined by a Scorched Carpet - new for me and rare for Guernsey. The larva fee don Spindle, which is not a shrub which occurs in Guernsey (although I am sure it exists in some gardens) so this was likely an immigrant.

Scorched Carpet - garden, 12 Jul 22

The next weekend was a nice early start to the summer holidays and so I could trap whenever it looked good. On 17th I had another new species for the garden - Bucculatrix thoracella. This species has only recently arrived in Guernsey and feeds on Lime - we have a lime tree overlooking the garden so it was not a surprise to have another five during the next week or so.

Bucculatrix thoracella - garden, 15 Jul 22

The couple of days around 17th and 18th were the hottest days of all and both nights I had 120+ species in the trap - not as many really rare stuff but lots of things I rarely see. On 17th July, I had another Stathmopoda pedella and a Cydia medicaginis, a tortrix which I had new for Guernsey a couple of years ago. On 18th there was a better selection including the third Stathmopoda pedella as well as some rarer species for me like Bright Wave, Lunar Thorn, Small Rivulet, Olive and G. janthinana. The best one was a tiny, dark moth of the family Heliozidae - no species from this family has ever been recorded in Guernsey before. Unfortunately subsequent investigations were unable to identify this to species - it was a female and either Heliozela hammoniella or Heliozela resplendella.

Heliozela sp. - Garden, 18 Jul 22

Thereafter, temperatures dropped a little and things were quiet but a final flourish on 21st July was a Dotted Rustic - a new macro-moth for Guernsey! A not-so-distinctive but actually quite-distinctive species to identify.

Dotted Rustic - garden, 21 Jul 22

Another target that I wanted this year was to take some photos of Purple Hairstreak, which I have never done before. These are not rare in Guernsey but I rarely see them, and when I do they are generally fluttering at the top of oak trees. This year seems to have been pretty good for them and people had been seeing them well at La Garenne around the isolated oaks. So I stopped on the way home from work and managed some pleasing shots.

Purple Hairstreak - Garenne, 4 Jul 22

Purple Hairstreak - Garenne, 4 Jul 22

Purple Hairstreak - Garenne, 4 Jul 22

Carrying on the lepidoptera theme, armed with my new caterpillar field guide I was keen to search for some larvae this year and was moderately successful. It is hard to find them without beating or sweeping however.

Grey Pug larva - Les Vardes, 9 Jul 22

Poplar Grey larva - Grande Mare, 20 Jul 22

Green Silver-lines - Les Sommeileuses, 27 Jul 22

Green Silver-lines - Les Sommeileuses, 27 Jul 22

Green Silver-lines - Les Sommeileuses, 27 Jul 22

Stigmella sp. - Les SomMEILEUSES, 27 Jul 22

Dioryctria sylvestrella - garden, 15 Jul 22

Bird-wise, there was nothing rare to see and even the heat didn’t push anything unusual in from the south (I was hoping for small flocks of Egyptian Vultures crossing the sea). The Balearic Shearwaters were present in four-figure flocks off Pleinmont as they have been most years now. By the end of the month there was the odd returning wader with two Common Sandpipers at Fort le Marchant on 22nd and the first Whimbrel at Pulias on 31st.

shearwater flock - Pleinmont, 9 Jul 22 - each pale speckle is one shearwater

Black-headed Gull - Perelle, 11 Jul 22

Of course, I managed a few insect-hunting sessions and found quite a few new species for me. One of my favourites being the tiny wasp below - Brachygaster minutus with its tiny waist tucking its abdomen into its body and how it holds its wings almost vertically.

Brachygaster minutus - Les Vardes, 9 Jul 22

Colletes fodiens - Les Vardes, 9 Jul 22 - is there a more photogenic species of insect?

male Pantaloon Bee - Grande Mare, 20 Jul 22

Gronops lunatus - L'Ancresse, 5 Jul 22

Hybos culiciformis - Les SomMEILEUSES, 27 Jul 22

Throatwort - ST. Peter Port, 13 Jul 22

Throatwort is a well-established alien which thrives on St. Peter Port walls. A Hummingbird Hawk-moth was feeding on this as I walked past.