Climate change brings more migratory butterflies to Austria

Climate change and more frequent dry, warm years are bringing increasing numbers of migratory butterflies to Austria, according to data from a citizen-science project reported by ORF. The project, “Butterflies of Austria,” marks its 10th anniversary in Tulln on Friday.

Since the project began in 2016, more than 31,000 volunteer researchers have submitted over 1.2 million butterfly sightings through an app, scientific director Helmut Höttinger told the Austria Press Agency. He cited the cardinal, the large and small wandering blues, and the pelargonium blue as species increasingly recorded in Austria despite being relatively rare there. The app has enabled the first records of the pelargonium blue in Vorarlberg, Carinthia, Lower Austria and Vienna.

The project is supported by the Blühendes Österreich foundation and the environmental movement Natur im Garten. Users can upload photos of butterflies for identification. A beta version of artificial intelligence has suggested species identifications since last year, while other users can also help identify sightings, discuss results and rate photographs.

The app includes profiles for 189 species, based on features such as colour, shape, flight period and location. It focuses mainly on butterflies active by day: profiles cover 157 of the roughly 215 day-flying species found in Austria. At users’ request, the app also includes 32 moth species, out of nearly 4,000 found in the country.

More than 29,000 people submitted nearly 138,000 sightings in 2025, giving researchers a broad picture of butterfly distribution across Austria. The peacock butterfly was the most frequently reported, with 6,415 sightings, followed by the meadow brown with 5,091 and the red admiral with 4,345. In total, users have reported 181 different day-flying species, or 84 percent of those recorded in Austria. Sightings of rare and highly endangered species can also help inform red lists.

The records show changes in butterfly flight times, Höttinger said. Butterflies are appearing earlier in the year, remaining visible later and producing more generations. The white-banded heath, which typically has one generation a year, is increasingly being seen in September and October as a partial second generation. Those butterflies cannot survive the winter, however, and do not contribute to the next generation.

Höttinger said much of the observation data, including many reports of moths, has yet to be analysed.