Admiral butterfly becomes annual visitor in Finland due to climate change

The admiral butterfly has become an annual visitor in Finland as a result of climate change. Jari Kaitila, director of the Finnish Butterfly Research Society, explains that just a few decades ago, sightings of this species were rare, occurring only every few years. Now, it is observed annually along the southern coastline. This year, there have been increased sightings from farther north, and areas near Pori have reported significant populations. The butterflies are often seen gathering nourishment from garden flowers and trees for their sap.

Originally from southern regions, the admiral butterfly is large and easily identifiable, with its northern wintering boundary reaching Germany. Kaitila notes that as recently as the 1970s, the species did not winter north of the Alps, but it now commonly winters in southern Germany. The admirals seen in Finland are mainly of the second generation that emerged from southern migrants.

In the autumn, some of these butterflies will migrate south. While there are occasional reports of wintering within Finland, cold conditions generally do not favor their survival through the winter.

The butterfly population in Finland is undergoing changes. Kaitila mentions differing opinions among enthusiasts regarding this summer’s sightings; some consider it poor, while he has noted several new species in his monitored sites. As climate change progresses, Finland’s butterfly species will likely continue to evolve, with some traditional species moving further north while new species migrate in from the south.

Kaitila emphasizes the importance of maintaining habitats for caterpillars, as the preservation of biodiversity is crucial for butterflies. He suggests that homeowners can support butterflies by leaving parts of their lawn uncut, creating suitable environments for various life stages of the insects, which also benefits other wildlife.