Big Butterfly Count 2021 : Update
BC have published and overview of the Big Butterfly Count HERE shows despite record participation in this very popular citizen science project individual insect count per record were the lowest recorded in its 12 year history. The average count in 2021 was down to 9 while in 2020 it was 11 and 2019 16. It discusses how much of this was due to weather in the recording period, and of course the diabolic effects of this year cold wet spring compared to recent warm dry springs of 2018-20. The very weak Jetstream this year has a lot to answer for but will it continue? The overwhelming effects were on double brooded species which will likely take a further year to recover. Highlights were Small Tortoiseshell remains poor although we buck this trend in Yorkshire with a boom. Red admiral had a good year in the south but Peacock had its worst year since 2012 and this certainly true in Yorkshire. The 3 week time slot of BBC and the delay in the second broods are really the take away story with some of grassland species actually having a good year and some species enjoying the damp.
September highlights : A very warm month but numbers still lag
Photo of the month By Chris Cox
The season has ended suddenly with numbers tumbling on our transect walks in the last week of the month, despite the good weather. The only significant nectar presently is Ivy , however our gardens are oasis with Sedums and Michaelmas Daisy drawing in Red Admiral and sometimes Comma. September temperatures have been well over average by near 3'C after the mid month mini heatwave hitting 27'C and more September records being broken! It has been quite sunny as well as dry but counts on our transects have often been single figures from mid month and rather disappointing overall. However, the Whites did have a better month and numbers have recovered well in the second generation. The Small Tortoiseshell boom continues and have often been the most abundant species in our gardens along with Small White. The main beneficiary of August damp has been Speckled Wood on its third generation reflecting the lush grass growth throughout August with counts on woodland transects having been large. It has earned its place as Butterfly of the month. There has been a small peak with the second generation Comma later in the month while Peacock has been mostly disappointing. A third generation of Small Copper was also evident in the middle of the month. Good numbers of migrant moths have been seen in the middle of the month. Quite a few moth traps yielded the rare migrant Clifdon NonPariel (Blue Underwing) and even Stripped Hawk Moth plus a Camberwell Beauty was spotted at Scarborough Mere. This is the last update of 2021 and we would like to thank all of you for your contributions with 300 records in September and 3000 so far this season. We ask our transect walkers to complete entering their data so we can bring you a timely analysis of 2021 soon. Please do keep entering your sightings.
Big Butterfly Count 2021: The Results are in!
Photo by Gavin Ashworth at Ribblehead on 12th August
August Highlights: The Tortoiseshell boom continues
Picture of the Month
Photo by Martin Roberts on 25th August at Huntington, York
As the end of the season approaches, a question I've been asked is "Did we have a summer?" Its easy to forget the July heatwave and while in Europe it continued well into August with some of the highest temperatures ever experienced, and devastating wildfires, our heatwave broke up in late July to a procession of rainy days and sunny intervals. August had average temperatures but has been, in large part, cloudy with mists and drizzle and any sun quickly extinguished with convective cloud bubbling up in minutes. Good sunny spells have been days apart and opportunities have been scarce to get out and explore and our transect walkers have struggled to find a suitable 'slot' to walk in, although the north of the county it has been significantly sunnier A blocking high pressure just west of Scotland established in the last 2 weeks drawing down cool NW winds from Scandinavia and the forecast into September is to remain dry but murky.
The August highlight has to be the continuing boom of Small Tortoiseshell's which in our fields and gardens is our most abundant butterfly even beating the whites. On August 7th in a local field with a broad flowering stewardship belt I noticed webbing, and, on closer inspection, the cause was large numbers of Small Tortoiseshell caterpillar webs. Over the next few days what must have been thousands of hungry mouths marched the full length of the field stripping every nettle back to a stump. Now they are emerging and Tortoiseshells numbers have boomed in the last few days with wide scale reports of huge numbers On my Buddleia they was certainly no 'social distancing'!
In contrast Peacock and Comma numbers remain low possibly because of the cold spring. You can speculate that weather conditions were not conducive to egg laying and by the time they were there, later in June, there were few surviving females. In fact Peacock webs were not seen until well into July, many weeks late, and adult emergence has been late, poor and extended. Red Admiral certainly shone as having a boom year on the Big Butterfly Count but only in the south of England however some made their way to Yorkshire supplementing earlier arrivals offspring and good numbers have been seen towards the end of the month.
Early August also saw a very large peak in Gatekeeper after a very good July for the brown family but by the third week they were about finished along with the Skippers. In contrast Meadow Brown continue with fresh specimens being reported till the end of the month . The woodland Hairstreaks survived well past the middle of the month and it was nice to see Holy Blue in good numbers mid month. Small Copper numbers also grew through the month and second generation Common Blue presently. The Scotch Argus was plentiful in its Wharfedale locations and was on the wing throughout the month. The migratory lowland Brown Argus are presently being seen on their second generation but as is usual with this sub species its hit and miss whether you see it. Wall did well in its normal haunts along the coast and uplands but was also seen in low numbers well distributed across the lowlands. Silver-washed Fritillary might just make it into to September and has had a stunning season being the most abundant butterfly In Bishop Wood for the last five weeks. Brimstone are settling into their woodland hibernation quarters where numbers are quite good feeding up on nectar nearby. Red Admirals and Painted Ladies will now start heading off on their homeward journeys gathering on the coast. Individuals will travel 100km a day but on this leg of their migration they are travelling at height waiting for the upper air streams to be south before commencing their perilous journey. Twice as many will leave than arrived originally.
August 13th UPDATE While many parts of Europe are recording some of their highest temperatures ever experienced, and devastating wildfires rage the UK sits largely under cool and cloudy Jetstream with an occasional high pressures systems creating a few dry days, but mostly its been very showery. Out in the fields spring sown crops are late but are gradually being harvested. Crop yields are good where they avoided the worst floods and the seasonal vagaries but overall its an average farming year. Plant growth has been abundant this summer and we have all had to cut our lawn very much more frequently. This has had a knock on in the abundance of most of our species and although our memory will always be of the 2021 as the spring with no butterflies, high summer has certainly redeemed itself . The Whites and Browns have been abundant with Small White now catching up. Gatekeepers are having a particularly abundant year and are maintained their numbers presently. There has certainly been a influx of Red Admirals reflected in the Big Butterfly count but Peacocks still lag well behind as do Comma and we are currently in a dip waiting the next generation of Tortoiseshells. Small Copper are now emerging in numbers and Holy Blue in large numbers and is at a peak. Second generation Wall are appearing presently in pleasing numbers. Scotch Argus still showing in Wharfedale. White-letter and Purple Hairstreak remain strong. Today, just 10 miles over the border in Derbyshire the first Brown Hairstreak was seen at Pleasley Pit transect, Mansfield where it has been present in good numbers for a few years now.
August 4th UPDATE As we pass the peak of the season with cooler showery weather prevailing this last week we have had some record counts form our transects. Meadow Brown numbers are past their peak but remain good and we have had a surge in Gatekeeper which are currently at their peak. The Whites are also at long last getting going with Large White leading the charge and Green-veined now emerging in good numbers, giving more hope that our species are making up for so much lost ground this spring. Only the Small white remains in the doldrums. Brimstones are emerging in numbers now and transect counts are rising. Silver-washed Fritillary is being reported from gardens more and more and is having a good year returning to places where it was seen for the very first time in 2019 and numbers remain at a record high in Bishop Wood. I've even had a report from a York man holidaying on the Scottish west coast that he had seen one there after seeing his very first in Bishop Wood a few days before. The Vanessids are at long last showing signs of getting going these last week with Peacock numbers rising fast and should continue to do so for at least another 2 weeks in an extended season because of the late start. Comma and Red Admirals are also having an emergence plus a few fresh Painted Ladies are being seen. Small Skipper have gone past their peak but Essex Skipper is about at its peak currently. Ringlet, Marbled Whites and Dark-green Fritillary are declining quite quickly. Speckled Wood are at a low although we can expect the next generation very soon in our woodlands . The next generation Common Blue on the lowlands are gathering numbers as are 2nd generation Small Copper and Brown Argus . Small Tortoiseshell numbers are falling as we await the next generation which should build up over the next fortnight. Holy Blue is approaching its peak presently. White-letter Hairstreak are just past their peak but Purple Hairstreak is still strong. If you have a large Oak tree near you, even stood on its own, stand underneath it between 5.30-7pm and watch on the lea side ( they hate wind) and count how many you see and pop it on our sighting page ; dedicated recorders are finding remarkable numbers of this much under recorded species.
Picture of the Month
Silver-washed Fritillary by Ian Brookes Pickering Woods 17th July
The heat wave reverses the fortunes of our summer species
Despite being one of the 5 warmest July's on record with the mid-month heatwave peaking near 30'C it was also wet. Rain was very local with some parts suffering flash floods, mighty thunderstorms and huge hailstones, others nothing . Global weather continues to be driven by weak and undulating Jetstream bringing heatwaves and floods in equal measure. It caused not only our heatwave but also that of the Western U.S, Middle East and China with sweltering temperatures. Northern Ireland had three record breaking hottest ever days in a row and Death valley recording the highest ever recorded temperature on earth of 54.4'C. At the same time the Jetstream dragged warm moist air up from the tropics as very slow moving fronts causing catastrophic rain events in the low countries, China and New Zealand. It was July 14th when the Jetstream moved north and a large high pressure anchored itself over top of the UK. This gave us the the heatwave which lasted over 10 days with our busiest day ever on our casual sightings page on Friday 16th as the mercury climbed above 25'C. The following days were some the hottest of the summer and actually drove some of our casual recorders inside!! even so we had welll over 700 sightings in July and nearly 3000 so far this year.
July: Winners and Losers
Our stoic transect walkers carried on regardless with counts recovering back to near normal during the first week of July . The hot weather coincided with the main emergence of many of our brown family leading to very high scores of Meadow Brown, 40% over last year, with over 1000 recorded on the Thorpe Marsh transect. Over a 1000 Ringlets were recorded on Forest of Flowers, York again 40% above last year It also rapidly turned into a 'Gatekeeper' Summer with more than double last years counts. Other species in July showing big gains were Small Heath at an amazing 260% over 2020. Speckled Wood were also double last year while Silver-washed Fritillary at its stronghold in Selby tripled! Dark Green Fritillary also had a good July with counts up a half and the spread through the county continues. Large Skipper also doubled but there are some loosers. Small Skipper is down to 75% of last year. The Large and Small White were halved continuing the trend of the bad start to the season but there is still some time in August for them to recover more. The big losers were our Nymphalids with Peacock counts only a tenth of last year, so far, and Comma and Red Admiral a half. In contrast Small Tortoiseshell has retained its massive increases of last year and is slightly up. Analysis table is presented below:
July 20th UPDATE 5 days of near 30'C and we are wilting but not the butterflies !! Few of us are venturing out to spot after our busiest day ever last Friday to near zero today. However transect counts continue at very high levels with many exceeding 200. Silver-washed Fritillary have seemingly exploded at its favourite site of Bishop Wood with more than double previous years counts. So, it is a great time to see mating pairs and lots of courtship dances. Female emergence has begun so male activity is feverish but in the hot weather they are stopping to take salts from the road frequently. The courtship dance is a most elaborate and unique and has never been filmed or photographed! Recent work by Ray Cannon from Scarborough has found that the insects actually touch during the loop the loop dance. The male passes under the female and then darts immediately upward so her antenna are drawn over the very evident sex brands of the male forewing. He then stalls so she overtakes and then he swoops back down underneath her and so the loop goes on lasting 1-2 seconds per loop. All this time she is going in a straight line down the ride. New season Peacock have now emerged and numbers are rising and also new season Brimstone and second generation Holly Blue. Ringlets and Meadow Brown remain at their peak but are joined in large numbers by Small Skippers and some fresh Essex . Large skippers are now declining quite fast as are Speckled Woods. A large peak in Large White and Green-vein white and good numbers of Hutchinsoni Comma . This summer form of the species will breed but not hibernate while the regular form will remain unmated till next spring and will go in and out of hibernation for the remainder of summer. Tortoiseshells numbers have dipped somewhat but Marbled White remain strong and Dark-green Fritillary are holding up but well past their peak now. We are also in the peak of the Purple and White-letters Hairstreaks. The Purple Emperor season started the middle of last week the latest season for many years by over three weeks but in Sherwood and North Notts numbers are strong and groups of us have been visiting to get familiar with this rapidly expanding species. Let me know if you want to see them and i can forward more details.
June Highlights: Why have there been so few butterflies?
Why have there been so few butterflies ? You might be forgiven to thinking this since the short burst of butterfly activity in the final days of May when the ghastly spring finally gave way to sunshine and warmth. This was promptly followed by the traditional June lull that has proven to be exceptionally deep and long because of the cold wet spring causing species to emerge two weeks late in many cases despite June being largely sunny , dry and warm . The disastrously low butterfly counts of May have continued till the third week of June when our summer species began to really take off, but, much slower to build than normal.
Picture of the Month by Chris Cox of Marbled White at Kiplingcotes Chalk Pit on the 26th June
Total counts were half those of 2020 over June from all our transects Apart from a short flush of Large White at the beginning of the month almost no whites have been seen flying throughout the month! Large Skipper were the first summer species to appear quite slowly then Meadow Browns and Dark Green Fritillary in the middle of the month with Ringlet a week later. Dark Green Fritillary continues to make progress with new colonies appearing northwards up the limestone ridge. Orange Tips, Green Hairstreak and Dingy Skipper continued flying to the middle of the month while they normally are all gone by the beginning of June. Marbled Whites also appeared in the third week of the month and as I write numbers are still going up, but, still no significant Small Skippers seen. Large Heath emerged on 9th , 2 weeks behind schedule, and have now peaked . The highlight of the month has to be the really good emergence of the first generation of Small Tortoiseshells with some recorders getting over 30 and a continuation of the good numbers carried over in hibernation from last year, in many cases they are the most common species seen this month. In addition reasonable numbers of migrant Painted Ladies appeared at the beginning of the month followed by Red Admiral later . The first White-letter Hairstreak on the 26th followed by Silver-washed Fritillary on the 29th, actually on time . Thank you for near 600 sightings this month despite the dearth and resultant waning enthusiasm.
Its is also possible that after 3 good summers for our butterflies that 2021 is an 'adjustment' in their trajectory which we should not be too surprised about.
Picture of the Month
Photo by Trevor Walton on May 12th at Hawnby
From Bad to much Worse! Is there Hope?
Could it get any worse than April? Well Yes! Nothing seen in the garden, transect walkers grounded or walks abandoned half way due to thunder, sleet or rain. Moth traps empty night after night. We are feeling the effects of 'La Nino' the cooling cycle linked to the 11 year cycle of sun spots. The result is a weak Jetstream which has sunk further south and west in an even more convoluted path than April, picking up low pressures and with cold arctic air still streaming into the north sea dumping their rain on the UK. It could prove to be the wettest May in 100 years and certainly in Yorkshire nearly 2-3 months rain has fallen. Average temperatures are down by over 2'C. Effectively we have had April in May. The grasses have flourished but flowering plants have been held back almost frozen in time at the beginning of May and are now at least two weeks behind. Peak daily temperatures have been 11-13'C and insufficient for flight and only Orange Tips seen in the brief sunny intervals. Transect walkers who managed to get out in marginal conditions saw very little with number less than half. Brimstone eggs laid on Buckthorn died in frosts or were predated by hungry birds . The weather finally broke on Friday 28th and a high pressure established over the UK and the long range forecast is for a good June. As I write Brimstones and even Small Tortoiseshell's, that had gone back into hibernation these last 7 weeks have reappeared. Yes , things can bounce back if the survivors get some flight time in the next 10 days. We have had more than 100 sightings come in in the last 3 days of May bringing the total for the month to near 400 although there has been many days of zero through this miserable month. We have had a run of nearly three good years for our butterflies and a disastrous spring is here to test that improvement's resilience. As always with butterflies, we should expect surprises!
This month best picture goes to Jessica Bone, taken in York on 25th April
Old Man Winter delivered icy kisses throughout the month which was dominated by northerly air streams and high pressure anchored over Greenland. Mereologically a weak polar vortex has lead to our jet stream being not only weak but undulating resulting in cold air being sucked out of the Arctic on all three northern hemisphere continents. Greece and Spain have suffered the largest snowfall for many years and the situation is mirrored in North America and Asia with crops ruined. Here our tender plants and blossom and even stinging nettles have been burnt. There was frost somewhere in the UK everyday of the month and Yorkshire had snow flurries for 10 days in a row over the Easter holiday. April was the driest, coldest, and sunniest almost ever recorded. Butterfly sighting however were good even with the cold and 300 sightings came into the website. Species continued to emerge illustrating its not just air temperature but the ground level microclimate warmed by the very sunny conditions led to Dingy Skipper being a day earlier than last year. Duke of Burgundy have appeared on time on the 26th. Orange Tip numbers have built up as have the Whites However the weather has seriously disrupted transect walking with some only achieving 1 walk so far this season. Thank you all those trying.
NB To have a chance of winning Picture of the month please do make entries in our sighting system of your latest pics.
Picture of the Month
This months best photo goes to Chris Cox taken on the Rail Trail at Keyingham VC61
The 2020 UKBMs results were published this month with Small Tortoiseshell being the stand out winner with some sites showing 300% increase in numbers. large and Small Whites, Brimstone, Holly Blue, Marbled White and Meadow Brown did well but even with this third good butterfly year in a row more species did badly than well. More on Yorkshire results HERE
It's been a long wait for the butterfly season to really start in Yorkshire taking till mid March for some sunny weather. This was followed by a 'Spanish plume' of warm air on 20-21st and then Saharan winds from North Africa on the 29th brought us our best spell with temperatures in the 20's and nearly 70 sighting records coming in during the last 3 days of the month. Its great to have 135 records in March into the new sightings system and over 200 so far this year from 33 recorders; see HERE. Thank you. The picture of the month goes to Chris Cox; see opposite. There have been very good numbers of our hibernators and some fantastic Brimstone counts from Bishop Wood and Brockadale plus a battered Painted Lady in Scarborough and a Hummingbird Hawk moth also seen. The first Holy Blue and Orange Tip have been seen and we can expect Speckled Woods, Wall, Small Heath and Green Hairstreaks any day. Nationally 2021 sees both the Large Tortoiseshell and the Clouded Yellow successfully overwinter on the Dorset coast, yet again indicating that they really want to become UK residents.
March saw the launch of our interactive Butterfly Atlas for Yorkshire which has won some international admiration as a first of its kind. Its a great tool to explore our countryside. It would be great if we can add our moth records as the next big challenge. Watch the demo video HERE and explore HERE
We also launched our online events and You tube channel to mark our progression to a new medium HERE. It has already allowed so much more interaction with our membership and brought people together throughout the county which was never practical before. We have used the opportunity to reinvigorate our formal recording which lags well behind our tremendous casual recording effort with training on UKBMS and species identification. There will be a number of transect restarting and some new ones this year including two of our best sites at Brockadale and Fordon Banks but we still need more interested volunteers with lots of spare time to repair the damage of the pandemic and staff losses from our charities.