Common Blue Polyommatus icarus


The Common Blue is the most widely distributed of the British blues and is commonly seen in a wide range of grassy habitats, including meadows, dunes, heaths, roadside verges and gardens.


The male is violet-blue with a fine black edge and white wing margins. Females also have white wing borders, and vary from the usual brown form with a hint of blue to those which are extensively blue varieties, all with orange marginal spots. The underside of the hind wings lacks the vertical twin spots of the Brown Argus.

Flight times

Generally double-brooded, it is on the wing in May and June, and again in August and September.

Food plants

Eggs are laid singly on a variety of leguminous plants, but it favours Bird's-foot-trefoil, Restharrow and Black Medick.

Common Blue
Common Blue - © Simon Jenkins.

Distribution Maps

Common Blue distribution map 2005-09
Common Blue distribution map 2010-14
Common Blue distribution map 2015-19
Common Blue distribution map 2015
2015 Summary
No of tetrads 492
First sighting 28/03/2015
Last sighting 11/10/2015
Common Blue distribution map 2016
2016 Summary
No of tetrads 353
First sighting 05/05/2016
Last sighting 23/10/2016
Common Blue distribution map 2017
2017 Summary
No of tetrads 360
First sighting 29/04/2017
Last sighting 25/09/2017
Common Blue distribution map 2018
2018 Summary
No of tetrads 592
First sighting 01/05/2018
Last sighting 26/10/2018
Common Blue distribution map 2019
2019 Summary
No of tetrads 560
First sighting 01/04/2019
Last sighting 28/09/2019
Common Blue distribution map 2020
2020 Summary
No of tetrads 536
First sighting 11/04/2020
Last sighting 20/10/2020
Common Blue distribution map 2021
2021 Summary
No of tetrads 471
First sighting 22/04/2021
Last sighting 07/10/2021

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