Friday, 30 August 2013

Brown Hairstreaks near Oxford

August 28, 2013:
The Brown Hairstreak (Thecla betulae) is only found in a quite restricted region of Britain, mainly in Oxfordshire and neighbouring counties. Like its close relative, the Black Hairstreak, it only occurs in close proximity to its larval food-plant, the Sloe.

Brown Hairstreaks are very elusive butterflies and spend most of the time high up in the trees but when the weather conditions are favourable they can come down to nectar on flowers whilst the females also descend to lay their eggs on the sloe.

Larval food-plant: the Sloe

They mainly occur in quite small, scattered populations so sightings rarely consist of  more than just a few individuals.

The morning was spent at Otmoor under ideal conditions but no sightings were made (although a female had been seen and photographed here earlier in the day). A second well-known locality, Whitecross Green Wood, was visited next but again none were seen. Other people also searching had no luck either (although there were two probables very high up in a master Ash tree). So, a return was made to Otmoor for one last attempt and this was rewarded with a male perched on bramble in dense vegetation. After making such a long trip it was pleasing to have success at last although it had taken four hours of almost constant searching.

A Red Kite circling over the site at Otmoor

Friday, 16 August 2013

Purple Hairstreaks near Newby Bridge, Cumbria

August 3: At an extensive oak wood near here, there are several  places where oak trees come down below road level. The elusive Purple Hairstreak (Neozephyrus quercus) butterfly, which spends most of the time high in oak trees feeding on the aphid honeydew on the leaves, can sometimes be seen to advantage from such a viewpoint.

In flight, the underside of the wings flash pale grey as distinct from the pale brown colour of their relative the White-letter Hairstreak (usually found in elms) and this helps to identify them. The upper side of the wing is usually shot with blue-purple and can especially show to advantage when the angle of the light is favourable. Seen at other angles the upper-side may appear dull brown. Photos below show some colour effects.

Monday, 5 August 2013

White-letter Hairstreaks at Boilton Wood, Preston

August 25-30. 2013:
In contrast to last year, White-letter Hairstreaks (Satyrium w-album) have been seen frequently in at least two places in these woods. Individual colonies are likely to be small but there are probably several of them scattered over the area.

The butterflies are most visible when they come down from the trees above (elms being the food plant) for nectar on flowers below; thistles and brambles seem to be their preferred choice. Often when feeding, they will stay on a single flower for a long time and become engrossed. They can then be approached closely.