Purple Hairstreak (Favonius quercus)
The Purple Hairstreak (F. quercus) is our commonest hairstreak, and may be located in oak woodland throughout southern Britain, and more locally elsewhere. It is often difficult to locate, due to its habit of flying high in the tree canopy, where it feeds on honeydew; groups of several individuals chasing one another is not an uncommon sight. However, the adults are occasionally seen feeding and basking at lower levels, on various small trees, shrubs and bracken. This butterfly is found across southern England and Wales, with scattered colonies further north. It is also found in parts of Ireland, mainly between Wicklow and South Kerry.
It is primarily found in woodland containing oak trees, the foodplant of the larva. However, the species can be found in any location where oaks occur, including lanes, parks, gardens, and other urban areas. The primary larval foodplants are Pendunculate Oak (Quercus robur), Sessile Oag (Q. petraea) and Turkey Oak (Q. cerris). Evergreen Oak (Q. ilex) is also used.
Eggs are laid singly (or less commonly, in groups of 2 or more), usually at the base of a plump oak bud, or cluster of buds, but can also be found on an adjoining twig and at various heights. They are laid on branches that are sheltered and receive full sunshine - such branches are therefore on the southern side of the tree. There also appears to be a preference for solitary trees, such as those found at the edges of woods, or those that form part of a hedgerow. Eggs are also most-often found on relatively mature trees (since these have the plumpest buds) on branches that are twisted and gnarled. Eggs are relatively easy to find in suitable locations during the winter months before the oak buds burst. Emergence occurs from the last week of June, through July and into August, with adults still being found into September. There is generally a peak at the end of July and early August, or later in Scotland. There is one brood each season.
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