Common blue butterfly Polyommatus icarus

As its name implies, the common blue is the commonest blue butterfly found in Norfolk, though in some years holly blues can also be very numerous. Its name only applies to the male, as the female common blue is dark brown with a variable blue blush at the base of her wings. In Norfolk the common blue has two adult generations each year and is an archetypal grassland butterfly, nectaring on grassland wildflowers and laying its eggs on bird’s-foot-trefoil.

Conservation status

The common blue is happily still abundant in Norfolk. However, since its habitat – floristically diverse, unimproved grassland – declined enormously in the twentieth century with the arrival of mechanised agriculture and chemical fertilisers, this beautiful butterfly has also doubtless declined enormously in recent decades. This is why the protection of its remaining sites is very important.

Related questions & advice

What is the difference between moths and butterflies?


Did you know? In bad weather and at night the common blue roosts, head down, on a grass stem. Often several of these little butterflies may be see together on a single stem of grass.
How to recognise
Where to see
When to see
How to help
Share this