Butterfly Conservation
Our colleagues in the South Wales Branch of Butterfly Conservation have asked us to watch out for, and protect the Brown Hairstreak. Richard Walker tells us that a BAP priority and Carmarthenshire specialist butterfly, the brown hairstreak, Thecla betualae, is strongly associated with most Carmarthenshire river corridors, below 150m altitude, particularly those with sheltered wooded areas. The butterfly needs young blackthorn growth, either young scrubby areas or unflailed hedges, close to woodland edge, on which to breed. Its range and populations have contracted, largely as a result of widespread practice of annual mechanical hedge flailing, which removes the young blackthorn growth & over-wintering eggs thus perish. With hedges, rotational trimming over several years is to be encouraged. However, leaving sheltered scrubby areas, like river bank "verges" is really helpful.
The Brown Hairstreak is an elusive butterfly that spends most of its life either high in the tree canopy or hidden amongst hedgerows. It is worth looking up at prominent Ash trees along wood edges to see if small clusters of adults may be flitting around a 'master' tree where they congregate to mate and feed on aphid honeydew. Alternatively, adults sometimes feed lower down on flowers such as Hemp-agrimony, Common Fleabane, and Bramble. The females are most frequently seen as they disperse widely along hedgerows where they lay conspicuous white eggs on young Blackthorn.
The butterfly is locally distributed in southern Britain and mid-west Ireland and has undergone a substantial decline due to hedgerow removal and annual flailing, which removes eggs.
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Butterfly Identifier