Dusky Thorn       Early Thorn
70.236 BF1915  –  Geometridae –  Larrentiinae – Ennomos erosaria – September Thorn – ([Denis & Schiffermüller], 1775) Adult Macro:  CAT 2 – Can be confused with other species – Can be confused with other species       PDF Icon – click for Adult Macro Verification Guidelines
Green –  Rare / Uncommon / Scarce   
Taxonomy:   Macro   >>  Geometridae  >> Larrentiinae
ID Difficulty:  amber  – care required in the identification process, as confusion with similar species is likely – quality photographs required.
ID pointers: Although similar to a few other species of “Thorns”, this one is generally plainer in appearance. September Thorn has orange “Leg Socks” – August Thorn has white “Leg Socks”.
Distribution:  (Last record: 29 July 2025 at Mickleover )  –  A resident that is locally distributed and uncommon in Derbyshire. Most records come from the south and east of the county. Easily confused with the rarer August Thorn.
General Comment: None Flight Period: August /  September /  October –  On the wing August – October – one generation Moth Activity: Nocturnal   – and is attracted to light Photographed: Yes –  Photographed By: Stephen Plant, Martin Roome, Christian Heintzen, Brian Hallam, Christine Maughan  © All Rights Reserved
*** Last updated on 7 November 2025 by RP ***
Wingspan: 30-35mm
Forewing: 17-21mm Food Plant: Oak (Quercus), birch (Betula) or lime (Tilia).
Last Recorded Year: 2025
Last Recorded By – Christine Maughan
Last Recorded General Area – Mickleover
Selected Images:  Allestree, Derby August 2021 – image by Stephen Plant ©  /  Chaddesden, Derby – August 2024 – Martin Roome © / Charlesworth – September 2024 – Christian Heintzen©/ Findern 29/6/2025 – Brian Hallam© / Mickleover ( 2025) Christine Maughan©

September Thorn - Geometridae - Ennomos erosaria - Stephen Plant
September Thorn – Ennomos erosaria – Stephen Plant
September Thorn - Martin Roome
September Thorn – Martin Roome
70.236 BF1915 - September Thorn - Christian Heintzen
70.236 BF1915 – September Thorn – Christian Heintzen
70.236 BF1915 - September Thorn - Christian Heintzen
70.236 BF1915 – September Thorn – Christian Heintzen
September Thorn - 29th June 2025 - Findern - Brian Hallam
September Thorn – 29th June 2025 – Findern – Brian Hallam
September Thorn - 29th July 2025 - Mickleover - Christine Maughan
September Thorn – 29th July 2025 – Mickleover – Christine Maughan
September Thorn - Geometridae - Ennomos erosaria - Stephen Plant
September Thorn - Martin Roome
70.236 BF1915 - September Thorn - Christian Heintzen
70.236 BF1915 - September Thorn - Christian Heintzen
September Thorn - 29th June 2025 - Findern - Brian Hallam
September Thorn - 29th July 2025 - Mickleover - Christine Maughan


Image Gallery

September Thorn - 28th June 2024 - Charlesworth - Christian Heintzen September Thorn - 28th June 2024 - Charlesworth - Christian Heintzen

Distribution Map for Ennomos erosaria

Found 119 records
    ↳ 16 from After 2025
    ↳ 50 from 2020 - 2024
    ↳ 53 from Before 2020
Flying
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

If the Map Layers function fails, just refresh the page and it should be OK after. Use the +- zoom on the top left, or on a tablet, use two fingers to zoom. Remember, the last layer you ticked is the one which displays the popup information - they sit on top of each other - de-select then re-select, to see the popup values.

Bedrock Geology ** indirectly affects moth distribution by influencing the type of habitat and food plants available in an area. In turn, this may affect the types of moths that can thrive, or where they can most likely be found.


NBN Atlas UK Distribution for – Ennomos erosaria

⚠️ Please wait for the map to load fully – do not click the link shown.


Note – the NBN Atlas datasets are listed in the map below and vary in their currency (uptodateness) – however, the map does give a general indication of the moth's distribution across the UK.

Visit NBN Site


Monthly Records By Year: Ennomos erosaria
( data includes both Larvae and Adult Stages )

Monthly Counts By Year: Ennomos erosaria
( data is based on 'Adult' stage records only. )


First/Last Recorded Dates: Ennomos erosaria
Adult-only & Anything [Larvae, Pupae, Adult, Mines]

Shading shows moth presence between dates

Click the colour discs below to Select/De-select as Required

Recordings By Year: Ennomos erosaria
( All data includes both Larvae and Adult Stages )
Annual Growth Rate (AGR): Ennomos erosaria
AGR: 1.44%   |   Total % Change: 31.3%


CUSUM Analysis: Ennomos erosaria
About this chart: CUSUM (Cumulative Sum) charts track long-term trends in moth populations [ filtered by 'Adult' and 'Mine' life stages ] by showing whether each year’s counts are above or below the historical average. Even small shifts build up over time, making trends of growth, stability, or decline easier to see. CUSUM highlights trend-consistency — asking: “Across the years, have moth counts mostly stayed above or below average?”
The data sample has 16 gap year/s here (zero records) between 2000 and 2025. The moth may have been present in those gap years, but no data was available. Too many year-gaps may exaggerate or skew the chart.

Counts for the current year (2025) are pro-rated based on data available up to month 10 (October) to provide a full-year equivalent.

ⓘ Purple line rises = years better than average; falls = years worse than average.
Peak (best year) Trough (worst year) Growth periods Decline periods
Population peaked around 2025, reaching above average levels. The lowest population point occurred near 2011, showing a significant decline.

What the Y-axis "Cumulative Deviation" means: Cumulative Deviation shows the running total of how each year’s moth population count differs from the long-term average. i

Hectad (10kmx10km) Coverage: Ennomos erosaria
( data includes both Larvae and Adult Stages )

Flight Periods – Indicative –vs– Recorded Data
Ennomos erosaria
( data includes Adult Stage only )

Flight Period chart – the grey hatched area above, which can cross one or more months, pictorially represents the best guess we have for this moth's flight periods [month/s]. The coloured lines represent the actual months seen in flight, from site observation records received between 2020-2025.

Records Behind the Map and Charts - Ennomos erosaria – 119 records available

Listed by Year - descending - scroll across to see all table columns

Site NameTetradDateCountStageSource
Walton ChesterfieldSK36U23/08/20251adultvc57_irecords_extract
Findern, DerbyshireSK33A15/08/20251adultvc57_irecords_extract
MellorSJ98Z14/08/20251adultvc57_irecords_extract
Shaw Farm, New Mills VCSJ98Y12/08/20252adultvc57_irecords_extract
Mickleover gardenSK33C11/08/20251adultvc57_irecords_extract
Glossop SK, UKSK09C07/08/20251Adultvc57_irecords_extract
Glossop SK, UKSK09C07/08/20251Adultvc57_irecords_extract
Dinting Nature ReserveSK09C06/08/20255adultvc57_irecords_extract
Findern, DerbyshireSK33A03/08/20251adultvc57_irecords_extract
Mickleover gardenSK33C29/07/20251adultvc57_irecords_extract
MellorSJ98Z17/07/20251adultvc57_irecords_extract
MellorSJ98Z16/07/20251adultvc57_irecords_extract
LittleoverSK33G12/07/20251adultvc57_irecords_extract
Chaddesden, DerbySK33T11/07/20251adultvc57_irecords_extract
Derby DESK33I05/07/20251adultvc57_irecords_extract
Findern, DerbyshireSK33A30/06/20251adultvc57_irecords_extract
MellorSJ98Z14/09/20241adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A06/09/20241adultvc57_irecords_extract
Charlesworth, Cown Edge LandslideSK09A02/09/20242adultvc57_irecords_extract
Park Haed, CrichSK35M01/09/20242adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A27/08/20241adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A23/08/20241adultvc57_irecords_extract
Ilkeston, DerbyshireSK44K17/08/20241adultvc57_irecords_extract
Chaddesden, DerbySK33T12/08/20242adultvc57_irecords_extract
Mickleover gardenSK33C11/08/20241adultvc57_irecords_extract
SandiacreSK43S09/08/20241adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A05/08/20241adultvc57_irecords_extract
Midway, Derbys.SK32A03/08/20241adultvc57_irecords_extract
Ilkeston, DerbyshireSK44K02/08/20241adultvc57_irecords_extract
Chaddesden, DerbySK33T31/07/20241adultvc57_irecords_extract
BelperSK34N29/07/20241adultvc57_irecords_extract
Allestree, DerbySK33P21/07/20241adultvc57_irecords_extract
Allestree, DerbySK33P21/07/20241adultvc57_irecords_extract
Ilkeston, DerbyshireSK44K19/07/20241adultvc57_irecords_extract
Allestree, Derby, Elm GroveSK34K15/09/20231adultvc57_irecords_extract
MellorSJ98Z09/09/20231adultvc57_irecords_extract
Garden, WaltonSK36U09/09/20231adultvc57_irecords_extract
MellorSJ98Z08/09/20231adultvc57_irecords_extract
Park Head, CrichSK35M20/08/20231not recordedvc57_irecords_extract
MellorSJ98Z19/08/20231adultvc57_irecords_extract
Findern GardenSK33A18/08/20231Adultvc57_irecords_extract
Findern GardenSK33A16/08/20234Adultvc57_irecords_extract
Findern GardenSK33A11/08/20232Adultvc57_irecords_extract
BelperSK34U10/08/20231adultvc57_irecords_extract
Findern GardenSK33A31/07/20231Adultvc57_irecords_extract
Findern GardenSK33A28/07/20231Adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A14/08/20221adultvc57_irecords_extract
Kirk Hallam, IlkestonSK44K22/07/20221adultvc57_irecords_extract
EA depotSK43G19/07/20221adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A18/07/20221adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A17/07/20221adultvc57_irecords_extract
Ninelands RoadSK28F16/09/20211adultvc57_irecords_extract
Birch ValeSK08I05/09/20211Adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A26/08/20211adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A20/08/20211adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A06/08/20211adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A02/08/20211adultvc57_irecords_extract
Longhurst Lane, MellorSJ98Z23/08/20201adultDanes_2019-2021
Findern, Derbyshire, DEAZSK33A17/08/20201adultvc57_irecords_extract
Longhurst Lane, MellorSJ98Z14/08/20201adultDanes_2019-2021
Findern, Derbyshire, DEAZSK33A11/08/20201adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A10/08/20201adultvc57_irecords_extract
Brook Road, ThulstonSK43B09/08/20201adultvc57_irecords_extract
Ninelands RoadSK28F07/08/20205adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A30/07/20202adultvc57_irecords_extract
Longhurst Lane, MellorSJ98Z28/07/20201adultDanes_2019-2021
Findern, Derbyshire, DEAZSK33A02/08/20192adultvc57_irecords_extract
Findern, Derbyshire, DEAZSK33A26/07/20191adultvc57_irecords_extract
Oaks Barn Cottage, Monyash Rd, Over Haddon, BakewellSK26D30/07/20111Adultvc57_danes_bc_data
Kedleston Park,DerbySK34F11/08/20071Adultvc57_danes_bc_data
Church St,Holloway,MatlockSK35I18/09/20061Adultvc57_danes_bc_data
Stocksmoor Farm, Ashover Rd, Old TuptonSK36S19/08/19981Adultvc57_danes_bc_data
Calke Park (Betty's Pool),TicknallSK32R10/08/19981Adultvc57_danes_bc_data
South Wood, Calke, TicknallSK32R25/07/19971Adultvc57_danes_bc_data
The Field,Shipley,IlkestonSK44M26/09/19961Adultvc57_danes_bc_data
The Field,Shipley,IlkestonSK44M26/09/19961Adultvc57_danes_bc_data
Stevens Rd, SandiacreSK43T27/08/19961Adultvc57_danes_bc_data
Stevens Rd, SandiacreSK43T19/08/19962Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G10/09/19921Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G10/09/19921Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G13/08/19921Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G13/08/19921Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G11/09/19902Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G11/09/19902Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G22/07/19891Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G22/07/19891Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G19/08/19883Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G19/08/19883Adultvc57_danes_bc_data
Pond House, Mapperley Res, IlkestonSK44G15/08/19862Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F11/09/19841Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F11/09/19841Adultvc57_danes_bc_data
Shipley Wood, Shipley ParkSK44L17/08/19843Adultvc57_danes_bc_data
Shipley Wood, Shipley ParkSK44L27/08/19821Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F22/08/19821Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F22/08/19821Adultvc57_danes_bc_data
Drummond Rd, IlkestonSK44R08/08/19822Adultvc57_danes_bc_data
Shipley Wood, Shipley ParkSK44L06/08/19824Adultvc57_danes_bc_data
Shipley Wood, Shipley ParkSK44L30/07/19821Adultvc57_danes_bc_data
Shipley Wood, Shipley ParkSK44L23/07/19822Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F19/09/19811Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F19/09/19811Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F16/09/19811Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F16/09/19811Adultvc57_danes_bc_data
Askew Grove, ReptonSK32D26/08/19811Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F18/09/19801Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F18/09/19801Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F18/09/19791Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F18/09/19791Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F14/09/19791Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F14/09/19791Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F31/08/19791Adultvc57_danes_bc_data
Shardlow Hall, Shardlow, Long EatonSK43F31/08/19791Adultvc57_danes_bc_data
Field Close, Hilton, Burton on TrentSK23K24/08/19761Adultvc57_danes_bc_data
Field Close, Hilton, Burton on TrentSK23K20/08/19761Adultvc57_danes_bc_data
Field Close, Hilton, Burton on TrentSK23K18/08/19761Adultvc57_danes_bc_data
Field Close, Hilton, Burton on TrentSK23K12/08/19751Adultvc57_danes_bc_data
The Old Manse, Ault Hucknall, GlapwellSK46S04/09/19681Adultvc57_danes_bc_data
Moorend, Beeley, MatlockSK26T10/09/19591Adultvc57_danes_bc_data
Moorend, BeeleySK26T10/09/19591Adultvc57_danes_bc_data

Dusky Thorn       Early Thorn

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