25/07/2017 Devils Dyke, Cambridgeshire

Chalkhill Blue: (male) One of the perks of getting sent away to survey in Norfolk is the ability to stop at some great places to see some great wildlife!
Chalkhill Blue: (female) So when I got asked to assist in some invertebrate surveys in Norfolk I made plans to visit the famous Devils Dyke right opposite Newmarket Racecourse.
Devils Dyke is an ancient monument that stretches for seven and a half miles, and reaches a daunting 10m (33ft) in height.

This archaeological treasure is also a Site of Special Scientific Interest (SSSI) as it is a haven for wildflowers, butterflies and a range of grassland insects come spring and summer.
(female underwing) The area sits between two very different ecosystems, one a rich peaty fenland and the other a chalk escarpment. The chalk and clay earth make a unique habitat for wildlife, including flowers, birds and butterflies, including the Chalkhill Blue.
(male underwing) Almost as soon as I arrived on the ridge I was confronted by dozens of blues of which almost all were Chalkhill Blues fluttering about the wildflowers.

These butterflies are part of the genus (Lycaenidas) which includes the Blues, Coppers, Hairstreaks of which the blues are particularly difficult to identify at times especially as the females tend to be brown!

Here is a classic textbook specimen with the pale blue wings going to black just before the white fringes. These can almost look white or chalky blue in bright sunlight when they are fresh which gives these stunning little butterflies their name.....the Chalkhill Blue.

Common Blue: (male) Another blue butterfly which was fluttering about on the ridge was the Common Blue.

(common blue male underwing) Although these butterflies are similar to the Chalkhill Blue you can see the darker blue of the common in flight, which catches your eye.

Once settled and sowing it's underwing you can see that the Common Blue as darker underwing, more pearls and a darker spot inside its underside forwing cell.

Chalkhill Blue: As I left the site and the sun came out and temperatures went up, even more blues were on the wing and I saw plenty of Chalkhill Blues mating on the tops of the flowers and grasses that carpet this ancient and excellent little place to visit.