Lasiommata megera
The first walls (aka wall browns), named after their habit of basking on walls, were encountered by lepidopterologists in Estonia in 2018. Although the species has a more southern distribution, climate warming is gradually expanding its range further north.
Walls are active during the day, but unlike other diurnal butterflies, which usually spend the day in vegetation and crevices, they find shelter in places like caves and tunnels instead.
The caterpillars of the wall are green, therefore often remaining unnoticed by foraging birds when active on grasses.
The underside of the wings is quite similar to that of the other two butterflies of the same genus found in Estonia. Differences occur on the upper side of the wings – it is more yellow and covered with a network pattern and more conspicuous eye spots.