Cornish Biodiversity Network  -  Supporting Wildlife Recording

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Cornish Red Data (2009)

The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.

Thecla betulae - Brown Hairstreak

Range & Status

Rare and found in southern England, west Wales and mid-west Ireland. There is insufficient data to give population trends. (Fox et a l., 2006). Widely distributed in Europe eastwards through Asia to Korea. Declining in many European countries (Asher et al ., 2001).

Regional Distribution

Found only in north Cornwall. Two recent records from Marsland (2005) remain to be

confirmed and a male and female were recorded at Petherwin Gate in 2004.

Habitat & Ecology

A butterfly of tree canopies, females can be found flying along hedges laying eggs on the young growth of Blackthorn Prunus spinosa . Colonies tend to favour extensive areas of hedges and woodland edge.


The national decline is blamed on the removal and regular flailing of hedges which destroys eggs and larvae. It may be expanding its range from north Devon into Cornwall.


Conservation should be at a landscape level with the reintroduction of traditional hedge management and to encourage landowners, farmers and highway authorities to stop trimming hedges annually. A UK BAP priority species.


I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.

The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.