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Chris van Swaay

@chrisvanswaay.eurosky.social
1.8K followers 517 following 389 posts

Ecologist and butterfly expert at Vlinderstichting and Butterfly Conservation Europe

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Chris van Swaay @chrisvanswaay.eurosky.social · 03/10/2026
This morning in our moth-trap, Griposia aprilina, in English Merveille du jour (!), in Dutch Diana-uil. We had one last year too. I know it is not that rare, but a spectacular and beautiful moth it is. Would it be living in our oak?
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Jolyon Troscianko @jtroscianko.bsky.social · 30/09/2026
🦋 Butterfly wing patterns create motion illusions that protect them from predators! Our new study (8 years in the making) is out in Nature today doi.org/10.1038/s415... @grahancock.bsky.social @esbriolat.bsky.social @scienceanna.bsky.social @lauraakelley.bsky.social @uniexecec.bsky.social
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Mathijs Bouman @mathijsbouman.nl · 30/09/2026
fd.nl/opinie/16137...
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Chris van Swaay @chrisvanswaay.eurosky.social · 29/09/2026
This comma (gehakkelde aurelia, P c-album) looks like a little dragon with a small c. Both 1st (July) and 2nd generation (>July) on Dutch Butterfly Monitoring transects have moved forward in time, the 2nd gen most, but that also got much smaller over time. Does hot 2026 even produce a 3rd gen now?
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Chris van Swaay @chrisvanswaay.eurosky.social · 28/09/2026
The Essex Skipper (zwartsprietdikkopje, T lineola) had declined by >90% on Dutch Butterfly Monitoring transects since 1995. In N America the species is an invasive, accidentilly introduced around 1910, still expanding. This photo from www.inaturalist.org/observations/231653174 shows it in NW Canada.
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Chris van Swaay @chrisvanswaay.eurosky.social · 25/09/2026
Another poor year for the Purple Hairstreak (eikenpage, F quercus) on Dutch Butterfly Monitoring transects. The species spends most of the time in the canopy of oak trees, and can be hard to find, which makes them difficult to monitor. In some years, as e.g. 2018, they descend in large numbers.
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Chris van Swaay @chrisvanswaay.eurosky.social · 21/09/2026
2026 gave us more butterflies on Dutch Butterfly Monitoring transects than 2023 and 2024 (these years were the worst since 1990), and a little bit more than 2025, especially in August. But beware of shifting baseline, numbers in most years in the 1990s were often twice as high as nowadays.
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Chris van Swaay @chrisvanswaay.eurosky.social · 19/09/2026
The Lesser Purple Emperor (kleine weerschijnvlinder, Apatura ilia) has been expanding north at a speed of ±10km per year and has now started to colonise SE of NL. If this speed continues it might reach me in Wageningen in ten years or so. The expansion is caused by climate warming.
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Emathion 📯 @emathion.bsky.social · 12/09/2026
The French made a short film about what could happen after all immigrants would follow the ‘white, angry old man’s’ advice to go back where they came from.
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Chris van Swaay @chrisvanswaay.eurosky.social · 09/09/2026
Distribution and trend of Dark Green Fritillary (grote parelmoer, S aglaja) in NL in 2026. It is painful to see how rare this species has now become, where it used to occur on semi-natural grasslands, woodlands, heathlands, coastal dunes, almost everywhere.
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Chris van Swaay @chrisvanswaay.eurosky.social · 08/09/2026
Migrant butterflies are having a good year on Dutch Butterfly Monitoring transects, with high numbers of Red Admiral and Painted Lady in summer, and lots of Pale Clouded Yellow now (the best year since the start of monitoring in 1990). Clouded Yellow is having an average year.
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Raoul Beunen @raoulbeunen.bsky.social · 04/09/2026
Verschuivende referentiekaders in beleid en beleidsevaluatie. Voor sommigen is het "ambitieus" als de Rijksoverheid probeert om over 10 jaar een doel te realiseren dat volgens het beleid uit de jaren 90 al in 2010 gerealiseerd had moeten worden. www.nu.nl/stikstof/640...
nu.nl
Stikstofpakket krijgt ruime voldoende: krimp veestapel is onvermijdelijk
De stikstofplannen van het kabinet betekenen een forse stap richting een oplossing van de stikstofcrisis, concludeert het Planbureau voor de Leefomgeving (PBL). Het gevolg is dat de veestapel flink za...
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Chris van Swaay @chrisvanswaay.eurosky.social · 02/09/2026
Since it recolonised NL in 2009, the spread north of the Mallow Skipper (kaasjeskruiddikkopje, C alceae) in the SW has been much faster than in the SE, despite having to cross stretches of water up to 5km regularly. The species prefers the clay-soils in SW and West NL and seems to avoid sandy soil.
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ZanBizar @zanbizar.bsky.social · 28/08/2026
Aaaaaah, wat is dat voor ding😱
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Chris van Swaay @chrisvanswaay.eurosky.social · 26/08/2026
The Pale Clouded Yellow (gele luzerne, C hyale) is having a good year on Dutch Butterfly Monitoring transects. In NL this is a migratory species, usually arriving from the east, now in its 3rd gen. Numbers this year so far resemble earlier top-years 2003, 2006 and 2025.
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Chris van Swaay @chrisvanswaay.eurosky.social · 20/08/2026
After a good 1st generation the Speckled Wood (bont zandoogje, P aegeria) suffers from the drought on Dutch Butterfly Monitoring transects. Numbers this summer are much lower. Still it remains a common and widespread butterfly who will recover once conditions become favourable.
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Chris van Swaay @chrisvanswaay.eurosky.social · 18/08/2026
Density of Ringlet (koevinkje, A hyperantus) per 1000m per 50km square in July 2026 on transects and 15min counts entered with the ButterflyCount app. Highest densities in Baltic, Poland, Czech Rpb and Denmark. A species sensitive to droughts, so numbers next year may be considerably lower.
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Chris van Swaay @chrisvanswaay.eurosky.social · 16/08/2026
Climate change has winners and (more) losers on Dutch Butterfly Monitoring transects, and the Grayling is one of the losers. So far 2026 shows even less butterflies than 2025. Although the species is typical for dry habitats, this used to be in an Atlantic wet climate, which has gone.
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Patrick Jansen 🐾 @patrickjansen.bsky.social · 16/08/2026
Dit spandoek - gezien langs de snelweg - is een leugen. Boeren bevéchten al generaties lang de natuur. En dat ging fout toen boeren gif, krachtvoer, kunstmest en enorme machines gingen gebruiken voor industrialisatie. Rijke boerennatuur en historisch cultuurlandschap zijn op grote schaal vernield.
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Philipp Laeseke @philaes.bsky.social · 02/08/2026
New paper out 😊 besjournals.onlinelibrary.wiley.com/doi/10.1111/...
besjournals.onlinelibrary.wiley.com
Plant species richness is key for restoring grassland butterfly assemblages
The results indicate that successful restoration of grassland vegetation and butterflies is strongly linked. To fully restore target butterfly assemblages, future grassland restoration should aim to ....
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Nature Ecology & Evolution @natecoevo.nature.com · 31/07/2026
Are current species conservation policies enough? New study indicates that common bird and common butterfly species across Europe are set to keep declining in the coming decades. www.nature.com/articles/s41...
nature.com
Predicted decline in common bird and butterfly species even under conservation policy scenarios in Europe - Nature Ecology & Evolution
Projections for 265 common bird and 144 common butterfly species across Europe under multiple sustainability scenarios, including those of existing conservation objectives, find no scenario in which t...
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Chris van Swaay @chrisvanswaay.eurosky.social · 30/07/2026
Lots of Scarce Coppers (morgenrood, Lycaena virgaureae) during today's walk in N Spain
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★ govert schilling @govertschilling.nl · 29/07/2026
lees dit. @sheilas.bsky.social overtreft zichzelf. helaas, gaat het niks uithalen, vrees ik 😢
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Chris van Swaay @chrisvanswaay.eurosky.social · 28/07/2026
European wildcat (Felis silvestris) in N Spain, so far we saw at least one each day on mown haymeadows.
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Chris van Swaay @chrisvanswaay.eurosky.social · 28/07/2026
Two newcomers in NL can cope very well with heatwaves as we have this year on Dutch Butterfly Monitoring transects and both have started their large 3rd generation very quickly after the large 2nd. The Short-tailed Blue colonised NL in 2009, the SSW in 2015.
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Julius-Maximilians-Universität Würzburg @uni-wuerzburg.de · 22/07/2026
#Europe is hindering its own efforts to protect bees, butterflies and other #pollinators, say 135 researchers. @ecoresearchzoo3.bsky.social et al. warn of serious consequences for #biodiversity and food security. ➡️ www.uni-wuerzburg.de/en/news-and-...
Bees make an important contribution to the pollination of wild plants and fruit trees: on the left, a honeybee on the flower of a sweet cherry; on the right, a bumblebee on a chicory. (Photos: Ingolf Steffan-Dewenter / University of Würzburg)
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Chris van Swaay @chrisvanswaay.eurosky.social · 19/07/2026
Kleine parelmoervlinder vandaag op de vlinderstruik in onze voortuin. Een nieuwe tuinsoort voor ons. Queen-of-Spain Fritillary today on the buddleia in our front garden in the centre of NL. A new garden-species.
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Chris van Swaay @chrisvanswaay.eurosky.social · 19/07/2026
The last few weeks we have seen high numbers of Queen of Spain Frit. (kleine parelmoer, I lathonia) on Dutch Butterfly Monitoring transects. The map shows densities per 1000m from 1-18 July. Highest numbers are locally in the coastal dunes and on extensive used fields and new nature in C and S NL.
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Chris van Swaay @chrisvanswaay.eurosky.social · 17/07/2026
The Hummingbird hawk-moth (kolibrievlinder, M stellatarum) has a good year on Dutch Butterfly Monitoring transects, where day-active moths are also counted. The Six-spot Burnet had its peak much earlier than usual, the Mother Shipton (mi-vlinder, C mi) interestingly was later than usual.
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IUCN SSC Butterfly & Moth Specialist Group @iucnbutterflysg.bsky.social · 15/07/2026
📣EUROPEAN RED LIST OF MOTHS PUBLISHED!📣 A m(amm)oth task - huge congratulations to the team! Spoiler: >3000 species assessed at the European level, 704 of them endemic. Ca. 25% are listed as Data Deficient & 11% threatened with extinction. op.europa.eu/en/publicati...
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Chris van Swaay @chrisvanswaay.eurosky.social · 13/07/2026
Where the Red Admiral (V atalanta) has a good year on Dutch Butterfly Monitoring transects, Peacock (dagpauwoog, A io) and Comma (gehakkelde aurelia, P c-album) are only doing so-so. The Small tortoiseshell (kleine vos, A urticae) has been down for the last ten years.
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Chris van Swaay @chrisvanswaay.eurosky.social · 12/07/2026
Just like the Queen of Spain Fritillary (kleine parelmoer, I lathonia) the Swallowtail (koninginnenpage, P machaon) loves hot weather. I found a few in every 15min count I did today in my region in South Veluwe (NL).
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Chris van Swaay @chrisvanswaay.eurosky.social · 11/07/2026
Big numbers of Queen of Spain Fritillary (kleine parelmoer, Issoria lathonia) in my region on South Veluwe. Veel kleine parelmoers vandaag op de Zuid Veluwe.
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Chris van Swaay @chrisvanswaay.eurosky.social · 09/07/2026
A very early Brown hairstreak (Thecla betulae, sleedoornpage) on our transect in the Wageningen Rhine-floodplains. Een heel vroege sleedoornpage op ons transect in the uiterwaarden bij Wageningen.
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Chris van Swaay @chrisvanswaay.eurosky.social · 05/07/2026
In the past the Marbled White (dambordje, M galathea) did several colonisation attempts in NL, but so far all failed and the species never managed to survive 10 years on its own. Vagrants are seen every year, but this year numbers on two sites are much larger. Lets see if this new attempt succeeds.
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Chris van Swaay @chrisvanswaay.eurosky.social · 05/07/2026
Mean number of butterflies per 1000m on Dutch Butterfly Monitoring transects per habitat last week. The high number on heathland comes from Silver-studded Blue (heideblauwtje, P argus), which can be very abundant. Overall Meadow Brown (bruin zandoogje, M jurtina) was the most abundant species.
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Jeroen van der Sluijs @jeroenvandersluijs.bsky.social · 22/06/2026
A new White Paper from eight major EU-funded pollinator projects warns that the resilience of Europe’s vital societal functions and food security are at stake if the EU fails to halt and reverse wild pollinator declines. #pollinators #moths #bees #bumblebees www.eurekalert.org/news-release...
eurekalert.org
Europe risks a crisis if it fails to halt pollinator loss, researchers warn
Eight EU-funded research consortia warn that Europe risks a crisis if it fails to halt pollinator loss. Their solution: a roadmap to reverse wild pollinator decline and protect managed bees.
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Chris van Swaay @chrisvanswaay.eurosky.social · 29/06/2026
The Pieris-whites have a good year on Dutch Butterfly Monitoring transects, esp. Large White (photo), Small White and Southern Small White have higher than average numbers at the end of June. The combination of enough rain a few weeks ago and Sunshine benefits these widespread butterflies.
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Raoul Beunen @raoulbeunen.bsky.social · 26/06/2026
Het kabinet kiest ervoor om oplossingen voor de stikstofproblematiek opnieuw op de lange baan te schuiven. Richting 2035 wordt (misschien) toegewerkt naar doelen die al in 2030 kunnen en moeten worden gerealiseerd. Op korte termijn gebeurt er (te) weinig. www.tweedekamer.nl/kamerstukken...
tweedekamer.nl
Weer ruimte voor boer, natuur en bouw: maatregelpakket voor landbouw, natuur en stikstof | Tweede Kamer der Staten-Generaal
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Chris van Swaay @chrisvanswaay.eurosky.social · 26/06/2026
Good numbers of Red Admirals (V atalanta) on Dutch Butterfly Monitoring transects. The combination of enough rain in spring and hot weather now is clearly positive for this nettle feeder.
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Chris van Swaay @chrisvanswaay.eurosky.social · 25/06/2026
Nederland heeft serieuze opgaven voor art. 10 (bestuivers) en 11 (graslandvlinderindex) van de Natuurherstelverording. Een belangrijke stap daarin zou natuurvriendelijk beheer van bermen zijn (zie www.groeneruimte.nl/nieuws/274011/?b=260624), als bv. kleurkeur (vlinderstichting.nl/kleurkeur).
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Caring Doctors @caringdoctors.bsky.social · 24/06/2026
Wanneer de realiteit fictie overtreft! Boven: fictieve voorspelling voor augustus 2050, uitgezonden door de Franse tv in 2014 om te waarschuwen voor de gevolgen van de opwarming van de aarde. Onderste: echte Franse voorspelling van 22 juni 2026.
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Chris van Swaay @chrisvanswaay.eurosky.social · 24/06/2026
On the Dutch Butterfly Monitoring transects we see a new wave of Painted Ladies (distelvlinder, V cardui) coming in from the south, probably with the hot air from France. This graph compares the mean number per week per 1000m with the top migration years 1996, 2003, 2009 and 2019.
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Chris van Swaay @chrisvanswaay.eurosky.social · 23/06/2026
Second generation of Map (landkaartje, Araschnia levana) is just starting at Dutch Butterfly Monitoring transect. On one or our transects we just spotted 4 fresh ones, this one actually has a lot of orange, as is more usual in the 3rd generation.
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Chris van Swaay @chrisvanswaay.eurosky.social · 16/06/2026
Poor numbers of Peacock (Aglais io, dagpauwoog) this spring on Dutch Butterfly Monitoring transects. We are at the onset of the first generation, though you can still find caterpillars. We hope for good numbers.
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Catalan Butterfly Monitoring Scheme @catalanbms.org · 28/05/2026
🦋📉 14 butterflies disappearing from the Mediterranean landscape #3 Black-eyed Blue (Glaucopsyche melanops) It has a single spring generation and inhabits open scrublands, grasslands and dry orchards, from low elevations up to around 1,000 m. 🔗 More information: catalanbms.org/en/especies/lycgme/
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Chris van Swaay @chrisvanswaay.eurosky.social · 06/06/2026
Occupancy-trend of the Chequered Skipper (bont dikkopje, C palaemon) in NL. After a long period of gradual decline distribution in 2024 and 2025 fell by almost 50%, esp. small populations were abandoned. Helas 2026 showed little recovery as far as we can tell now.
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Chris van Swaay @chrisvanswaay.eurosky.social · 03/06/2026
Enjoy this 5min film (in English) on how a potato field in N NL was transfered into a butterfly haven: vimeo.com/292261901 Geniet van dit filmpje van maar 5min over hoe een aardappelveld is veranderd in een vlinderparadijs door Willem van Hemmen: vimeo.com/292261901
vimeo.com
Insect Guardian - Butterfly paradise
82 year old Willem bought an remote potato farmfield back in 1980 and transformed it into a butterfly paradise. For almost 40 years he works the land with shovel and scythe in order to preserve the bu...
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Chris van Swaay @chrisvanswaay.eurosky.social · 02/06/2026
With numbers of Painted Ladies (distelvlinder, V cardui) rising on Dutch Butterfly Monitoring transects, it's a good moment to put this invasion in perspective. The graph shows a small influx, comparable with 1996 and 2003, and smaller than 2009 and 2019. But lets see how it continues.
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Chris van Swaay @chrisvanswaay.eurosky.social · 27/05/2026
Hornet moth (Sesia apiformis) in Wageningen floodplains (NL). We see them every year, but still fun. Hoornaarvlinder (Sesia apiformis) in Wageningse uiterwaarden. We zien ze elk jaar, maar het blijft leuk.
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