Common Blue

Polyommatus icarus

The common blue butterfly or European common blue is a butterfly in the family Lycaenidae and subfamily Polyommatinae. The butterfly is found throughout the Palearctic and has been introduced to North America. Butterflies in the Polyommatinae are collectively called blues, from the coloring of the wings. Common blue males usually have wings that are blue above with a black-brown border and a white fringe. The females are usually brown above with a blue dusting and orange spots. Source

Where it is now

In the last 8 weeks this insect was recorded 675 times across 21 areas (each area is a 5 degree square).

See the Common Blue on the live map

Movement and weather

Each season it is first heard regularly where daytime highs are around 16°C (typically 11 to 18°C, from 10 areas).

Over the weeks it was present in the past year, its centre in Europe ranged from 43°N in April to 58°N in June, about 1,700 km apart.

Arrival dates

The week it was first heard regularly in each region, after at least six weeks away. Dates differ from south to north, so a region has a range.

Download every area as CSV

Figures are effort corrected and come from automatic sound identification, which makes mistakes. How this is measured and how it compares with human observers.