Species Account

Select species and region:



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.

Regional breakdown:

Year first recorded19041883188318831961
Year last recorded20142014201320142014
Number of records601385226467
Number of individuals5414758482114
Unique positions3242247116
Unique locations2943267415
Adult records561324824366
Immature records01000

For the county, we have a total of 581 records from 187 sites. First recorded in 1883.


1915 September Thorn 04
© Damian Money
1915 September Thorn 03
© Nick Lawman
1915 September Thorn 02
© Terry Box, 20 Aug 2012
1915 September Thorn 01
© Terry Box, 7 Sep 2007

Species Account

Sutton & Beaumont, 1989: Quite widely distributed in woodland although it often strays to other habitats and seems to spread to upland areas slightly more than the previous species [Dusky Thorn]. Only seems frequent in the centre of the County and parts of the North York Moors.

2012 (CHF): August and September Thorns can be tricky to separate if you are not familiar with them. One tip is that September Thorn holds its wings at a much steeper angle. The two species have quite different distributions in the county with August Thorn in the east and September Thorn in the middle of the county. The range overlaps a little in the south. Despite the names, the flight times are almost identical. Numbers are doing fairly well in the centre of the county.

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