Species Account

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Summary Data

Season (Adult / Immature):

National Status: Common

Local Status: Scarce and thinly distributed or restricted resident.

Local Record: Grade 3   See here for explanation

Flight time: One generation, Jul-Oct.

Forewing: 17-21mm.

Foodplant: Oaks and birches. limes, Beech.

IMPORTANT - Please note that the maps and accounts are provisional, subject to change and further update.  The whole dataset still needs to go through the final verification process and it is likely that a very small number of records will not satisfy the present requirements and there are other records that have not been formally submitted.  The information is for guidance only.

Record breakdown:

Year first recorded196119851961
Year last recorded201120112011
Number of records564531234
Number of individuals1351582818
Unique positions496110
Unique locations446100
Adult records561521226
Immature records000

For the region, we have a total of 1234 records from 100 sites. Earliest record on file is in 1961.


September Thorn 2
© Julian Francis
September Thorn
© Julian Francis
1915 September Thorn 03
© Dave Foot
1915 September Thorn 02
© Tom Morris
1915 September Thorn 01
© Terry Box, 23 Sep 2006

Species Account

Similar species: 1912 Ennomos quercinaria (August Thorn) and 1914 Ennomos fuscantaria (Dusky Thorn).

For further information refer UK Moths.

Davey, P., 2009: A frequent species in southern Britain, more local further north, the larva feeding on oak (Quercus spp.), lime (Tiliae spp.) and birch (Betula spp.). In Dorset, the moth is restricted to old birch and oak woods; it is seldom found in open country. It has also been trapped in suburban areas such as Wimborne, where lime (Tilia platyphyllos x cordata) is likely to the host plant. September Thorns between mid-July and mid-August are smaller and paler than their late-summer/early-autumn counterparts; debate surrounds the possibility that the two forms are in fact two ecologically separate races.

See background to species accounts.  Index of Vernacular names - Search - Random Species