For all who more or less know the butterflies of NW Europe, but find the diversity of the Balkans overwhelming, there is a masterclass on "Eastern continental and Balkan butterfly species" by Rudi Verovnik on 11th February at 15h CET. For more details see butterfly-monitoring.net/epic-butterfly

The Small Heath (hooibeestje, C pamphilus) experienced a huge crash in 1991 on Dutch Butterfly Monitoring transects, maybe caused by extreme cold nights (-8C) in April. Though numbers are slowly going up, the species never fully recovered. #vlindermaand

Brown Hairstreak (sleedoornpage, Thecla betulae) is a local species in NL, and can be found in the centre of the country where sandy soils meet clay, often in urban areas, as well as in S Limburg (SE NL). This distribution has been more or less unchanged for the last 30 years. #vlindermaand

The Green-veined White (klein geaderd witje, P napi) is still widespread and common in NL, but numbers have halved since 1990 on Dutch Butterfly Monitoring transects. With the species preferring moist circumstances, the increasing number of droughts by climatechange surely have effect. #vlindermaand

The Sooty Copper (L tityrus, bruine vuurvlinder) has shown serious declines, esp. in the north of NL. Only on the Veluwe (centre) the situation is better. This species is vulnerable to N deposition (fartmann.net/downloads/ar...).

The Gatekeeper (P tithonus, oranje zandoogje) is doing well in de coastal dune-transects of the Dutch Butterfly Monitoring Scheme, but shows declines in the Agricultural area (where most transects are in verges) and esp. woodland. We don't know why the trend on woodland is so negative. #vlindermaand

Large and Small tortoiseshell (grote en kleine vos, N polychloros and A urticae) show opposite trends in their distribution in NL. The Large T used to be rare, and is now widespread, esp. in the eastern half. The Small T is now rare outside the W and N. #vlindermaand

As NL is at the NW-edge of the distribution of the Swallowtail (koninginnenpage, P machaon) we see periods of expansion (2009-2013 and 2018-2025) alternate with periods of retraction (2014-2017). #vlindermaand

Camouflage: Green Hairstreak - Groentje - Callophryx rubi. #vlindermaand

Around 1990 the Queen of Spain Fritillary (I lathonia, kleine parelmoer) in NL was restricted to the coastal dunes. After 2000 the inland was colonised, but not from the coast, but from the southeast (B and D). In 2024 the species crashed, some recovery in 2025. #vlindermaand

www.trouw.nl/duurzaamheid... Mooi interview met @dickvanhoffen.bsky.social. Onderbouwd tegewicht tegen de mantra ‘Alles moet dood’ uit de BBB-gelederen…

Even though the Meadow Brown (M jurtina, bruin zandoogje) is the most abundant butterfly on Dutch Butterfly Monitoring transects, it is missing or rare in some parts of the country. #vlindermaand

In the 1990s the Comma (P c-album, gehakkelde aurelia) would have a large extra Sept generation. However this Sept generation became smaller and smaller and nowadays only a few butterflies are present in Sept and most of the summer butterflies go straight into hibernation. #vlindermaand

Before 1990 Brimstones (G rhamni, citroenvlinder) would be more abundant in summer than in spring, but this has shifted over time. The only explanation I can think of is that they go into hibernation sooner after appearing in summer, maybe to avoid summer heat. Other ideas welcome. #vlindermaand

The Orangetip (A cardamines, oranjetipje) expanded its range in NL in W and N direction and now covers the whole country, though numbers in new colonised areas still low. The color of the dot shows the first year with a record after 1990. #vlindermaand #oranjetipje

Losses of specialist and expansion of thermophilic generalist macro-moths in nature reserves of Central Europe: www.sciencedirect.com/science/arti...

The slow expansion of the Marbled Fritillary (braamparelmoer, Brenthis daphne) in NL has surprised me, in B and D it easily moves 10-20km per year. Even in de SE the density is still relatively low. Apparently the quality of the habitat in NL is not good enough to move further north.

Distribution- (occupancy-) trend tells a different story than the population trend. The distribution of the Gatekeeper (P tithonus, oranje zandoogje) in NL is stable, where the populationsize has declined with 70% between 1992 and 2010.

The Large Skipper (Ochlodes sylvanus, groot dikkopje) is not only declining in NL but in the whole EU, where we can see a reduction in populationsize with appr 50%. www.butterfly-monitoring.eu #eBMS

The small Eastern Baton Blue (Pseudophilotes vicrama) declined in most of N and C Europe, but is still widespread in SE Europe. It occurs on dry grasslands on sandy or stony soils, south-facing slopes with grassy vegetation, on steep slopes, in rocky gullies, on railway embankments, on road verges

Female Meleager's Blue (Polyommatus daphnis, getand blauwtje) are really beautiful butterflies. In S and SE Europe they are widespread, in C Europe local.

Northern Chequered Skipper (C silvicola, geelbont dikkopje): Vulnerable (A2b) in EU (www.bc-europe.eu/webpage.php?...) because of population declines on European Butterfly Monitoring transects in eBMS (www.butterfly-monitoring.net).

Really nice paper from @tiff-ki.bsky.social & co. shows no overall decline in butterfly species richness in Sulawesi over 166 yrs, but changing communities with endemics & forest specialists declining. Short-term trends unreliable measures of long term. royalsocietypublishing.org/doi/10.1098/... 🌏

We are also deeply saddened that the Madeiran Large White, Pieris wollastoni, is now officially extinct: it was last seen in 1986. The full report can be downloaded here www.bc-europe.eu/documents/68...

The new European Butterfly Red List is published today, with worrying findings. Over 1/4 (28%) of Europe’s 442 species are threatened with extinction or are close to being so. The situation is far worse for our 148 endemic species, 40% are now threatened or nearly so www.bc-europe.eu/webpage.php?...

The new European Butterfly Red List shows that butterflies are under increasing threat across Europe, with the number of species at risk of extinction up from 37 to 65 (73%) in the last 10 years. See our Press Release www.bc-europe.eu/documents/68...

Ecoloog over het teveel aan stikstof: ‘De zieke heide kan worden hersteld, maar elk medicijn heeft bijwerkingen’

Crazy but well worth 4 minutes of your day.

Now the 2025 field season for butterflies has come to an end, it is a good moment to look back at the great work of the recorders of Dutch Butterfly Monitoring transects. Almost 400,000 butterflies counted in 2025 on 1372 locations, 8,5 million since 1990 on 212,327 km. Thanks for all hard work!

2025 will mark another bad year for the Dark Green Frit (grote parelmoer, S aglaja) with numbers comparable to 2023 and 2024 in NL (=low). Once widespread throughout the country, and numbers ten years ago still good, now reasonable numbers only on Vlieland and N-Texel (the islands in the NW).

2025 marks a very bad year for the Glanville Frit (veldparelmoer, M cinxia) in NL. Only the coastal population had >10 butterflies, on the inland ones the species almost vanished. Poor weather in 2024 made few larvae enter last winter.

The Painted Lady (distelvlinder, V cardui) was only seen in low numbers on Dutch Butterfly Monitoring transects this year. It is a migrant species, and the graphs show that 1996, 2003, 2009 and 2019 had large invasions, the other years just a few managed their way to NL.

Veel meer natuur nodig om nuttige insecten voor de landbouw te behouden

The Swallowtail (koninginnenpage, P machaon) had a good year on Dutch Butterfly Monitoring transects, clearly better than 2024 (though we have had better years). Exceptional was the large 3rd generation, which is usually small in NL.

The addition of flexcounts, as eg 15min counts, to Dutch Butterfly Monitoring transects, makes it possible to produce detailed flight curves. Although 2025 was warmer, the White Admiral (kleine ijsvogel, L camilla) had an earlier start in 2024. Also watch the small 2nd gen.

An interesting pattern for the abundance of the Common Blue (icarusblauwtje, P icarus) on Dutch Butterfly Monitoring transects: a large and early 1st gen, followed by a smaller 2nd gen (which is normally larger than the 1st gen) and a small 3rd gen right now. Food quality in summer has been poor.

Semi-natural grasslands as a nature-based solution for climate change mitigation: An assessment of carbon and plant communities across age gradients... www.sciencedirect.com/science/arti...

The Hummingbird hawk-moth (kolibrievlinder, Macroglossum stellatarum) is a climate opportunist from the south, and they love warm weather. Numbers on Dutch Butterfly Monitoring transects were high this summer, and the next generation just started. So watch out for these 'hummingbirds' in your garden

It's been a while since we had a good migration year for the Pale Clouded Yellow (gele luzernevlinder, C hyale) on Dutch Butterfly Monitoring transects, but finally numbers are comparable to 1992, 2003, 2006 and 2017. The species declined in C Europe, the origin of our butterflies.

After a great start this spring the Peacock (dagpauwoog, A io) had a poor 1st gen in July, and the 2nd gen is more or less absent on Dutch Butterfly Monitoring transects. Numbers are now much lower than in 2024.

Yesterday I bumped into this fresh male Sooty Copper (bruine vuurvlinder, L tityrus), of what will probably become a 3rd gen. Also a new site for me on S Veluwe. This species shows a large decline, esp. in the north of NL, since I started butterflying.

Not that long ago in August Buddleia's could be covered with Small Tortoiseshells (A urticae, kleine vos). On eBMS transects and 15min counts (www.butterfly-monitoring.net) this butterfly is now restricted to higher elevations or latitudes. Open squares=counted in that period.

An update of the Pieris-whites on Dutch Butterfly Monitoring transects show they all have a relatively poor 3rd gen this year. The reason recorders feel they 'only count Whites' is because all other species are doing even worse, maybe except for C hyale and C argiades in the SE.

Clouded and Pale Clouded Yellow (C hyale+crocea, gele en oranje luzernevlinder) are migrants in NL and show large year-year fluctuations in density on Dutch Butterfly Monitoring transects. Before 1980 C hyale was considered more abundant, now it is C croceus. Numbers for 2025 up to now.

Up to July numbers of Red Admiral (Vanessa atalanta) were good on Dutch Butterfly Monitoring transects, but since then they plumeted and now mid-August we have a negative record, as never before there were so few of them counted. This is most probably linked to poor nettle quality.

We had a large 1st gen of the Common Blue (P icarus, icarusblauwtje) on Dutch Butterfly Monitoring transects. But where the 2nd gen is usually twice as big, in 2025 it was even smaller, probably because of poor foodplant quality as a result of dry conditions in spring. Will we have a 3rd gen?

As a true climate opportunist the Short-tailed Blue (C argiades, staartblauwtje), which arrived in NL in 2009, profits from hot and dry summers caused by climate change. Numbers on Dutch Butterfly Monitoring transects now higher than ever.

The mean number of butterflies on Dutch Butterfly Monitoring transects is now very low as compared to other years since 1990 (though 2024 was worse). With such low numbers flowers in gardens also stay empty: there are simply no butterflies around to visit them.