Friday, 19 October 2012

2012 Butterfly Surveying

Adonis Blue Polyommatus bellargus, male.
I have just sent off my records to STERF so they can be included in their annual butterfly survey report for France. This year the weather was against the butterflies and the surveyors. I didn't manage to survey all my transects every month because if the weather is wet (actually raining), cold (below 16C) or windy (more than 30km/hour) it is not worth doing even in the middle of summer. Luc Manil, who co-ordinates the project from the Museum National de l'Histoire Naturelle (MNHN) announced quite early on that it was the worst year for butterflies since 2006. My observation for this year is that now that I look back and compare this year and last year it is obvious how much cooler, windier and cloudier this year has been in comparison. Whenever STERFists go out to survey their transects they first note the temperature, level of wind and percentage of cloud cover. This year my survey days have been about 10 degrees cooler (generally in the low 20s rather than the low 30s). Last year I mostly had a light breeze, this year it has been moderately breezy. Last year it was sunny, this year it has been cloudy or very cloudy.

Ilex Hairstreak Satyrium ilicis, ovipositing on Downy Oak Quercus pubescens.
This year all but a few species did fairly badly. Two of the most noticeable exceptions were the Map Araschinia levana and the Peacock Inachis io. Both were unusually abundant all season. The species that was most noticeable by its absence was the Small Heath Coenonympha pamphilus. This small brown grassland butterfly is normally so common you disturb one with every step, but this year the most I recorded in a single transect was 9. Mostly I saw just a single individual in each transect. Other brown grassland butterflies, such as Meadow Brown Maniola jurtina, normally the most abundant species in France, were also quite scarce.

Brown Argus Aricia agestis on Yorkshire Fog.grass
Nevertheless, I did manage to take some very nice photos of butterflies, and I include some of them in this post. Overall I recorded 696 individual butterflies and 41 different species. Last year I saw more than twice as many individuals, and 4 more species. The most abundant species this year was the Marbled White Melanargia galatea, with 289 individuals, all but 5 of which were seen in June. No other species even came close to this level of abundance, not even the usual suspects, Meadow Brown (last year's winner) and Gatekeeper Pyronia tithonus.

Essex Skipper Thymelicus lineola on Field Scabious Knautia arvensis.
You can read my May report here, June report here. For comparison, here is the 2011 overview.

Essex Skipper on Red Clover Trifolium pratense.

Knapweed Fritillary Melitaea phoebe on Ribwort Plantain Plantago lanceolata.

Large Skipper Ochlodes venatus.

Marbled Fritillary Brenthis daphne on Blackberry Rubus agg.

Marbled White male, on Field Scabious.

Short-tailed Blue Everes argiades, male.

Scarce Swallowtail Iphiclides podalirius on Knapweed Centaurea sp.

Small Skipper Thymelicus sylvestris on Yorkshire Fog Holcus lanatus.

Violet Fritillary Clossiana dia.

17 comments:

Colin and Elizabeth said...

Gorgeous photos, Susan. You should be congratulated on them! How on earth do you manage to count so accurately? I'm afraid most of my entries include a 'best guess' element as they are far too flighty and just won't stop on command to be counted. A beautiful post.

SweetpeainFrance said...

I've arrived to make the same comment that I marvel at your photographs and how you can capture such accuracy and beauty.

Tim said...

Interesting... as usual... Susan.
Not counting the Peacocks and Red Admirals [all those nettles, donchaknow], both still around, our most noticeable butterflies here were Holly Blue, Small Heath, Meadow Brown and Gatekeeper... in that order... the Hollies being the most abundant all the time, the others seemed to be most abundant here when the drought was on... we also noticed more Marbled Whites this year... but very few Clouded Yellow... last year, they were the other way round.
Very few Swallowtails... Scarce or
otherwise... a goodly number of Great Banded Grayling... but only one spot of Lesser Purple Emperor.
Having read your comments above, I am now wondering whether the 'moistland' meadow of ours played a part in the numbers here? If such, another string in the bow against the destruction of the weir.

[This from the laptop... although I read your report from the tiny Archos screen... which doesn't do justice to the pictures!]

Susan said...

Elizabeth: My transects are all fairly short and I walk very slowly. The main problem I have is with double counting of the sneaky ones that wheel round while you are not watching -- I'm sure that happens nearly every transect. I do the count and then on the way back I do photos -- sometimes I confirm an ID later using the photos, but the survey sheet will just say * Hairstreak, for example.

Glad you and Sweetpea like the photos.

Tim: Your observations are almost the exact opposite of mine (again) so there must be something about la Forge this year. Last year my north facing wooded sites did significantly better than others, and that was because they coped with the drought better. Something along those lines must be going on at your place. In a normal year you should get Meadow Brown, Gatekeeper and Small Heath in that order, but the fact that you have them in good numbers this year is bucking the national trend and my observations. I didn't record a single Holly Blue for the survey, and hardly saw one during the year. I suspect your Hollies are one or both of the Short-tails Everes spp. Your meadow is exactly the sort of habitat they thrive in and they were the one group of blues that did well this year.

It was a bumper year nation wide for Marbled Whites, but they had a good year last year too. My observation is that it was a good year for Swallowtails too (both sorts), but whereas last year I had GBGs leaping out of every bush in late summer, this year, far fewer. Clouded Yellows often only get underway late, and there are still quite a few around in the orchard.

I haven't seen a single Lesser Purp this year, and far fewer Southern White and White Admirals -- they had an exceptional year last year, as woodland species were a bit more buffered against the drought.

Tim said...

Susan, they were definitely Hollies... no orange visible on the underwing edge at all when settled... overall very pale blue... I've only got E.argiades in my book [R & R Gooden - Butterflies of Britain and Europe]... so E. alcetas is new to me... I've just written a reference to this blog entry in the book.
But they were nothing like either of the Everes... don't forget, I am now looking at them at 'real' size thanks to the "Macronoculars".
I actually don't "think" I've ever seen either of the Everes spp.

When I brave the elements, I will send you a link to a picture on my flickr space which I think is a Black 'Airsreak... hopefully you'll be able to confirm... the person who gave us the nod said they were White-letter... but they definately ain't!

Ken Broadhurst said...

I agree about the beautiful photos. Chapeau !

Susan said...

Tim: well, there ya go -- there's something about la Forge, for sure. Also for sure are your Black Hairstreaks - good record!

Ken: Merci beaucoup.

GaynorB said...

fantastic pics, Susan. They really are wonderful. Bravo!

Keep up the good work.

Tim said...

Susan... thought from Pauline...could it be that the land here forms an 'accessible' island amidst a monoculture.. there are 'flight paths' that can be followed from the woods on the ridges either side... and if you include Richard's etang and his grazing field beyond that, up to Moulin de Favier... quite a large island. By 'flight paths' I am thinking of not just the odd tree line, but also the weedy ditches.

They are good pictures... especially the shallow depth of field shots that really isolate the butterfly [Skipper shots, and Marbledwight and Glandular Frit are all super.]

Susan said...

Gaynor: many thanks :-)

Tim: yes, anything that allows metapopulations to be mobile and find sanctuary can be very significant in difficult years. It does seem that the Aigronne valley is a very important pathway locally.

I'm really please with these shots. I like the Marbled Frit too -- which was a lucky single shot -- those two grass stems crossing in the foreground -- grrr! I've been reading Ted MacRae and Alex Wild lately, who give really good tips on insect photography, post-production and even cover the differences between point-and-shoot v DSLR (so much of what is written is for DSLR, and it is a different ballgame...) I'm learning a lot.

ladyjustine said...

Such wonderful photographs. The marbled white is beautiful.

Susan said...

LJ: Marble White's are very photogenic because of their smart black and white, but actually I'm disappointed that the scabious burnt out. For me, the skipper photo is much better.

Nicole said...

Gorgeous photo's...I am no expert on butterflies (just love to see plent of them about!) but can report we regularly saw swallowtails (can't confirm which sort...) this summer in the flowerbeds and we (girls and I) had commented there seemd to be more of these than usual this year...
Do not recall seeing any of the small blue butterfly in your photo that I have forgotten the name of already this year..have definitely noticed them in previous years.

chm said...

I've been coming late to this post and I wholeheartedly agree with any one who says it's a great one, with wonderful photos and beautiful butterflies.

I do agree also with Ken's hat!

Susan said...

Nicole: my records show more swallowtails than usual this year too, and the last 2 years have been very bad for almost all the blues.

chm: thanks!

Tim said...

Nicole's observations from the top edge of the valley are also very interesting.... they had all the Swallowtails and we only had a few sightings... and there's only about two kilometres between the two houses... but about 40mtrs height difference.... ?

Susan said...

Tim: yep, they are much higher and dryer than you. Swallowtails hilltop, so they may just ignore your place.