Westcott, Bucks - the year 2017 in review

Butterflies

22 butterfly species were seen in the garden during 2017 and amongst them was one which hadn’t been recorded here before, Swallowtail Papilio machaon - not a species that was even on my radar!  In typical Swallowtail fashion it didn’t settle and was seen flitting around for several minutes on 13th June before disappearing over the hedge, never to be seen again.  Although lovely to witness, it was so out of context as to set alarm bells ringing and a little bit of detective work eventually revealed that one had escaped from a local breeder’s conservatory the previous day.

The other 21 were all expected species and it was good to see Ringlet Aphantopus hyperantus back in the fold regularly after the previous year’s rather odd absence.  Two species which did really well were Red Admiral Vanessa atalanta and Speckled Wood Pararge aegeria but many of the others were once again in short supply, in particular Peacock Aglais io  and Small Tortoiseshell Aglais urticae which have in the past appeared here in very large numbers during the “buddleia season”. 

Red Admiral, Westcott 21st May 2017

Common Blue Polyommatus icarus was recorded only twice, one example from each of its two broods, despite being quite widespread in the local area.  In contrast it was good to see White-letter Hairstreak Satyrium w-album for the fifth year running, this time almost daily between 19th June and 6th July.  Holly Blue Celastrina argiolus started off really well during April and May but only two examples of its second brood were noted here during August and none thereafter.  Small Copper Lycaena phlaeas isn’t seen here every year but in 2017 it put in a very welcome handful of appearances and, true to form with its preference for yellow flowers, all were second brood specimens found visiting our rudbeckia.

Small Copper, Westcott 2nd September 2017

 

Moths

What a fantastic year 2017 proved to be for moths at Westcott!  Once again the twin-30wt actinic light was run on almost every suitable night (279 in all), supplemented on 32 occasions during the height of the season by the 125wt MV as there is just enough room to run two traps without the lights interfering too much with each other.  The garden produced a record-breaking moth species count of 662 identified, comprising 326 micro-moths and 336 macro-moths, each of those three totals being the highest ever recorded here in a single year.  The overall count of individual moths at the site came in at just under 29,000.  While that was better than the previous year’s disappointing low of 26,697, it was nowhere near as good as in 2014 (32,910) or 2015 (33,941).  

The garden’s lepidoptera list continues to accumulate new species with surprising regularity even after 13 years of recording here and 31 more were added during 2017 to take it up to 967 (31 butterflies, 936 moths).  The new moth arrivals are listed below:

4.056	Stigmella speciosa (mine on Sycamore)	26th Aug
4.074	Ectoedemia sericopeza (mine on Norway Maple)	12th July
7.012	Nematopogon schwarziellus *	16th May
15.058	Phyllonorycter hilarella *	14th Mar
15.063	Phyllonorycter maestingella *	19th May
20.017	Argyresthia glaucinella *	19th June
32.043	Depressaria sordidatella *	26th July
34.008	Cosmopterix scribaiella *	21st June
35.061	Ptocheuusa paupella *	10th July
35.156	Recurvaria nanella *	25th July
35.160	Stenolechia gemmella *	2nd Sept
38.045	Elachista utonella *	6th July
47.002	Phaulernis dentella *	4th June
49.005	Epagoge grotiana	9th July
49.022	Ptycholoma lecheana	26th May
49.086	Acleris logiana *	1st July
49.138	Cochylis molliculana *	2nd June
49.3431	Thaumatotibia leucotreta *	2nd Aug
62.025	Dioryctria sylvestrella *	17th July
63.054	Cydalima perspectalis	25th Sept
63.090	Agriphila inquinatella *	12th July
66.008	Fox Moth Macrothylacia rubi	28th May
70.031	Mocha Cyclophora annularia	23rd Aug
70.127	Fern Horisme tersata	6th July
70.164	Pauper Pug Eupithecia egenaria *	26th May
72.035	Rosy Footman Miltochrista miniata	10th July
72.076	Clifden Nonpareil Catocala fraxini	30th Sept
73.261	Grey Arches Polia nebulosa	18th June
73.294	Southern Wainscot Mythimna straminea *	19th June
73.338	True Lover’s Knot Lycophotia porphyrea	21st May

* confirmed via dissection, with grateful thanks to Peter Hall.

Searching for leaf-miners in the garden during 2017 produced 39 species identified at that stage of development but only two of them were new to the site list.  However, of that pair, Ectoedemia sericopeza was a particularly good find because the larva burrows into the samara (winged fruit) rather than the leaf of Norway Maple Acer platanoides and the evidence of its presence is thus not quite so easy to spot.  I was prompted to search for the mine because an adult came to the trap a couple of days earlier which was almost certainly sericopeza but it escaped before it could be potted.

Phyllonorycter hilarella emerged indoors from a leaf-mine collected on 31st October 2016 on our Goat Willow Salix caprea, hence the out-of-sync date.  Phyllonorycter mines on that particular food-plant need rearing through to be sure of the species and this is now the third I’ve had from the same tree in the garden, the others being viminiella and salicicolella.  The very plain-looking Depressaria sordidatella was another good find thanks to dissection and it certainly wouldn’t have been identified correctly otherwise.  This appears to be only the third known site for it in Bucks.  However, Cosmopterix scribaiella (the first record for Bucks) and Ptocheuusa paupella (second record for Bucks) were probably the most exciting adult micro-moth finds here during the year.  Both are species of damp places, the larvae of the former feeding on common reed while those of the latter use a number of plants including common fleabane.    

Mine of Ectoedemia sericopeza. Westcott 12th July 2017

 

Cosmopterix scribaiella, Westcott 21st June 2017

 

Ptocheuusa paupella, Westcott 10th July 2017

 

Recurvaria nanella was recorded as a vacated leaf-mine in October on a pear tree just down the road and it was very nice to have an adult confirmed from the garden as well.  The very small gelechiid Stenolechia gemmella, unfortunately deceased, was a lucky find in the bottom of the trap and proves the worth of sifting carefully through the detritus there each day to check for anything of interest.  Phaulernis dentella was found indoors on the kitchen window and appears to be the first Bucks record since Victorian times of this nationally scarce epermeniid.  Of the tortricid species, Epagoge grotiana and Ptycholoma lecheana occur fairly regularly in nearby woodland so their appearance here in the garden comes as no great surprise.  Acleris logiana was once thought to be confined to the north of Scotland but since the 1990s there has been an upsurge in records of this birch-feeding species from counties in southern England.  The first for Bucks was found at Marlow Bottom on 5th November 2009 and there have been about a dozen subsequent sightings where genitalia have been checked to ensure separation from the rather similar Acleris kochiella.  The latter species is a garden regular here at Westcott (its larvae feed on elm) and that’s what I initially thought the 1st July record would be, but the dissection proved otherwise.  A second and more obvious specimen of logiana made a garden appearance in October and I also had it at three other sites in Bucks during the year.   

Ptycholoma lecheana, Westcott 26th May 2017

 

Acleris logiana, Westcott 25th October 2017 

 

Cochylis molliculana began colonising the south coast of the UK during the 1990s and has gradually moved northwards, the first record for Bucks following in 2010.  Numbers seemed to increase quite dramatically during 2017 and I had ten more individuals in the garden during July, August and September as well as several sightings elsewhere in the county.  The False Codling Moth Thaumatotibia leucotreta was another specimen which unfortunately passed away before it could be photographed although it was alive when potted up from the outside of the trap.  There are a handful of previous records for Bucks going back to 1996 but this appears to have been the first outdoor specimen caught at a light trap, the others having been found indoors or as larvae discovered in imported fruit.  It is an adventive tropical species but records of it seem to have been on the increase recently.  The males have noticeably hairy hind tibiae which are clearly visible in the picture below. 

Thaumatotibia leucotreta, Westcott 2nd August 2017

 

The Box Moth Cydalima perspectalis, now our largest resident micro species, will doubtless be on everyone’s garden list fairly soon because it seems to be multi-brooded and is spreading at an alarming rate.  Being an accidental introduction from Asia which was first recorded in Europe in 2006 (and in the UK from 2008), it presumably has few local predators as yet.  Agriphila inquinatella seems an unlikely arrival here but both my image and Peter’s dissection confirm it to be that species.  My only other July sighting of inquinatella was at Rammamere Heath five nights earlier and I suppose it could conceivably have found its way back with me in the car but it would then have had to avoid the nightly garden trap until the 12th.

Cydalima perspectalis, Westcott 25th September 2017

Agriphila inquinatella, Westcott 12th July 2017

 
The addition of nine new macro-moth species to the garden list was an unexpected bonus, especially after having only three the previous year.  Fox Moth has to be amongst the best of this particular bunch, especially as the example caught was a male.  I had thought the species was similar to Oak Eggar in that males flew only during the daytime but that turns out not to be the case because this one came to the actinic trap well after dark.  However, my three previous light-trapped specimens in Bucks, two from Stoke Common and one from Bernwood Forest, were all females as expected. 

Fox Moth, Westcott 28th May 2017

 

The Mocha, Fern and True Lover’s Knot were some distance away from their normal habitat so will presumably have been wanderers from the Chilterns, while the closest Rosy Footman colony that I’m aware of is in Bernwood Forest which lies downwind of the garden by about 8km so really not all that far away.  True Lover’s Knot in fact appeared twice, the second example being caught here on 9th July.  Pauper Pug was an interesting find as it is currently a Red Data Book species but may now be expanding its range.  The larval food-plant is lime, which as Common Lime Tilia x vulgaris we have in the garden and around the adjacent churchyard, while there are also a few examples of Small-leaved Lime Tilia cordata elsewhere in the village.   

Mocha, Westcott 23rd August 2017

 

True Lover's Knot, Westcott 21st May 2017

 

Rosy Footman, Westcott 10th July 2017

 

Although I thought I might have to wait a few more years to see it at Westcott, Clifden Nonpareil was not entirely unexpected due to its continued march northwards and there is plenty of aspen locally for its caterpillars.  This particular garden visitor was found hiding beneath our kitchen windowsill several metres away from the actinic light, as shown in the first picture below which was taken by torchlight just before dawn as I was closing up the moth-trap.  Although superficially similar to Red Underwing Catocala nupta when at rest, its size alone was an obvious give-away.  This highlights the importance of doing a sweep around the garden after each trapping session to check for moths which haven’t quite made it into the trap!

Clifden Nonpareil, Westcott 30th September 2017

 

Clifden Nonpareil, Westcott 30th September 2017

 

The other two new macro-moth species were less of a surprise, Grey Arches being found in small numbers in one or two of the woods around here and there are established colonies of Southern Wainscot at a couple of wetland sites within just a few kilometres of the garden, at Wotton Underwood and at Calvert.

 
There were several other species which, although not garden first-timers, were sufficiently uncommon here to warrant a mention.  The smart long-horn Nemophora degeerella put in a daytime appearance on 18th May, ten years almost to the day since the last one was recorded in the garden.  The tiny clover-feeding gracillariid Parectopa ononidis was recorded twice during July, its first appearance here since 2007.  The grey-coloured Ermine Yponomeuta sedella was a welcome visitor on 23rd July and has been seen here only once previously.  It made a pleasant change from some of the other white yponomeutid species which are fairly regular visitors to the garden light-trap but can’t be safely determined to species.  Metalampra italica (recorded three times in July following its first appearance two year previously), Ethmia dodecea (visits on 21st June and 1st July) and Oncocera semirubella (one appearance on 19th July) are all species which are currently expanding their range locally so will hopefully appear again.  The uncommon crambid Sitochroa verticalis came to light on 14th July, its second garden sighting here, while stablemate Sitochroa palealis also turned up a couple of times that same month.

Yponomeuta sedella, Westcott 23rd July 2017

 

Amongst the macros, Small Yellow Wave Hydrelia flammeolaria appeared twice, its first record in the garden since 2006, while a visit from Small Seraphim Pterapherapteryx sexalata was only the second ever seen here.  A male Gypsy Moth Lymantria dispar put in an appearance on 23rd August, another presumed wanderer either from the colony in Aylesbury or from those in West London and was the first seen here since 2005.  A smart Silver Hook Deltote uncula visited the actinic trap on 21st June, the second recorded here and only the ninth for Bucks as a whole. 

Gypsy Moth, Westcott 23rd August 2017

 

Silver Hook, Westcott 21st June 2017

 

The highest counts for individual species in 2017 were broadly back to where they should be, at least in ratio to each other when one takes into account my absence for much of August.  In particular, Heart and Dart Agrotis exclamationis recovered to achieve double the 2016 total and regained its expected place near the top of the table.  Black Rustic Aporophyla nigra seemed to do particularly well, achieving a garden count of 305 which is an increase of more than 100 over its previous highest total.

 

	Top 20 Highest Counts, 2017
20	Black Rustic	305
19	Common Wainscot	307
18	Square-spot Rustic	317
17	Small Square-spot	344
16	Common Quaker	346
15	Brimstone Moth	347
14	Beaded Chestnut	394
13	Flame Shoulder	425
12	Agriphila straminella	435
11	Hebrew Character	484
10	Dark Arches	511
9	Chrysoteuchia culmella	516
8	Pleuroptya ruralis	525
7	Smoky Wainscot	568
6	Setaceous Hebrew Character	655
5	Lunar Underwing	847
4	Common Footman	879
3	Acentria ephemerella	1190
2	Heart and Dart	1391
1	Large Yellow Underwing	1481

The pairs of species below - actually a trio in the case of the Minors - were mostly recorded as aggregates and, if they had been identified to species, at least four of them (Common Rustic Mesapamea secalis, Marbled Minor Oligia strigilis, Uncertain Hoplodrina alsines and Rustic Hoplodrina blanda) would have slotted in somewhere in the league table above.

	Aggregate Counts, 2017
3	Mesapamea species (Common Rustics)	322
2	Oligia species (Minors)	577
1	Hoplodrina species (Uncertain & Rustic)	1230

Finally, a reasonable selection of migrant moth species appeared in the garden during the year.  Hummingbird Hawk-moth Macroglossum stellatarum recovered to more normal levels but the numbers of other species were for the most part not as good as in 2016.  The main exception was Vestal Rhodometra sacraria of which there was a significant invasion into the UK during the autumn.  The table below gives the number of visits and first/last noted dates for those species which could reasonably be regarded as migrants here:

Plutella xylostella	16	10th March	23rd July
Crocidosema plebejana	1	28th September	-
Nomophila noctuella	18	9th June	15th October
Udea ferrugalis	8	18th June	4th December
Vestal	8	17th October	3rd November
Gem	1	2nd November	-
Hummingbird Hawk-moth	37	13th June	2nd September
Dark Sword-grass	8	22nd June	11th August
Small Mottled Willow	4	10th July	29th July
Scarce Bordered Straw	3	22nd August	24th September
Silver Y	53	15th May	20th November

Crocidosema plebejana, Westcott 28th September 2017

Vestal, Westcott 24th October 2017

 

Hummingbird Hawk-moth, Westcott 1st August 2017