Purple Hairstreak. © 2019 Gillian Thompson.
Although this butterfly is described as being quite common in favourable locations, its habit of living high in the tree canopy means it is rarely encountered. You will sometimes see this butterfly feeding on honeydew deposited by aphids lower down, especially during long hot summers and it can be reliably encountered in the morning below Oak trees as the adults emerge from their chrysalis.
Look around the tops of Oak trees (even isolated Oaks may support a small colony) during the flight period where you may see several in flight. Binoculars recommended!!
The Purple Hairstreak is found in woodland where Oak trees occur. It is also possible for a single Oak tree with no other woodland around to support small colonies. Disused railway lines where semi-mature Oaks exist can also support colonies of this small and elusive butterfly.
The larvae of the Purple Hairstreak feed on Oak (Quercus).
See maps below. Distribution text required.