This butterfly is increasingly believed to be more common than previously thought, and probably quite common. In fact, I have even heard it suggested that it is one of the commonest butterflies in England. It is often missed as it spends much of its time high in the treetops and is most active in late afternoon and early evening when it can be seen (best with binoculars) engaging in aerial skirmishes high in the canopy. In one locality I happened to chance on an area of low shaded shrubbery alongside a dried up river bed in the heat of the afternoon and found I had disturbed a number of quercus that were presumably escaping the heat. In 2009 I chanced upon a low tree in which ten or more were resting in the shade in mid-morning, difficult to spot as they were so inactive. As they were in the shade, photography was rather difficult.

However, as they spend most of their time in the canopy of Oak trees (the larval hostplant), any opportunity for photography is welcome. They feed on aphid secretions ("honeydew") and do not take nectar from flowers nor take salts or moisture from the ground.

The male has extensive purple on both upperside wings and the female has reduced purple patches, mainly in the basal area of the upf. The undersides of both sexes are very similar although H&R says that the unh marginal markings are more distinct in the female. It rarely settles with wings open, which is a shame; the last time I saw this was in 2004. Quercus is not dissimilar to the Spanish Purple Hairstreak (Laeosopis evippus) in this respect.

In the new European taxonomy, this species now has the scientific name Favonius quercus.

observations

a female with limited blue/purple in the basal area of the upf, the male having a more extensive blue/purple patch extending to the margins.

maybe the slightly more distinct marginal marks suggest female.