Forester Moth Surveys in Argyll 2014
Introduction
Forester is a UK BAP priority species, being confined in Scotland to the Argyll coast and to
parts of the Solway coast including the Butterfly Conservation reserve at Mabie Forest. Both
South (1980) and Heath & Emmett (1985) mention that its distribution included Invernessshire/Moray but there are no historical records for this area held by the National Moth
Recording scheme.
Forester on Bracken in 2008 and Forester Distribution Map.
1
In Argyll, Forester is found in three main areas: around Oban; the Isle of Seil and Kilmartin
All sites are therefore quite coastal but in England, Forester also occurs inland. Although
there is a good scattering of post 2000 records in England, there has been a large decline
during the 20th century which has been attributed to the loss of un-improved grassland. This
fact is an important indicator of its general habitat requirements which are not well
understood.
Distribution of Forester in the UK showing an inland distribution in England, Wales and Northern Ireland but
coastal distribution in Scotland (gold squares: pre-2000; blue squares: post-2000). Credit: National Moth
Recording Scheme
Heath & Emmett (1985) write of Forester “late May to early July, inhabiting damp meadows,
rides & clearings in woods, sandhills, chalk downs & limestone hills. Moth flies in sunshine,
rests on foliage in dull weather. Both sexes are attracted to and feed at flowers, especially
those of Ragged Robin. Although local, Forester is the commonest and most widely
distributed species of its genus in the UK, its range extending from southern England into
Wales & northward to Argyll & Inverness-shire. Widely distributed in Ireland.”
2
Waring & Townsend (2003) says “flies in sunshine, both sexes spend much time feeding at
flowers such as Ragged Robin, Field & Devil’s-bit Scabious, clovers & Viper’s Bugloss,
even in cloudy weather. Mating pairs are seen in the afternoon and males sometime fly again
an hour or so before sunset on warm evenings. Open habitats, ranging from damp neutral
grassland to limestone grassland, chalk downland, acid and sandy heathland, mature coastal
sand-dunes and woodland rides & clearings.”
Of distribution, Waring & Townsend (2003) writes “Local & well distributed in England &
Wales where many colonies have been lost as a result of intensification. Very local in western
Scotland, in Argyllshire and the islands of Jura, Lismore & Mull. Widespread but local in
Ireland.”
Kate Findlay’s MSc Thesis on Forester’s habitat requirements
During June 2013, an undergraduate, Jack Higgs, and a postgraduate, Kate Findlay, from the
University of Kent visited three areas of the UK to attempt to characterise the habitat
requirements of Forester: chalk and limestone downland in Dorset; heath and woodland rides
in East Anglia; and damp grassland in Argyll. To date, only Kate Findlay’s work has been
written up (Findlay, 2013), and her results are discussed below.
Ten Argyll sites with historical Forester records in the last ten years were visited and Forester
was found at three: Dun Ladain Fort (2); Carnasserie Farm (3); and Barndromin (1). In
England, Forester was found at nine of 23 sites which indicates that a single visit to a
historical Forester site in England has a 39% chance of detection compared with 30% in
Scotland. Both results are good and provide encouragement for further Forester surveys.
A number of habitat variables were determined for each site using data recorded within 30 1
m2 quadrats at 10 m intervals along a structured walk: sward height measured with a drop
disc; sward height variability; percentage disturbance; percentage tree or shrub cover;
Common Sorrel density; Common Sorrel patchiness; and flower density. Management
information was also obtained; presence/absence of mowing and grazing including grazing
spp; and whether or not site was protected with a conservation designation.
Each site was given a score of suitability for Forester based on the presence/absence of
Forester in 2013 and the number of years since the last record of Forester. Multiple regression
was then used to determine the best explanatory variables. Owing to problems with
correlations between explanatory variables, not all variables could be used in these analyses.
The best models were found to be those that included percentage tree or shrub cover alone
and percentage tree or shrub cover and whether or not a site was protected: less tree/shrub
cover favoured suitability as did a conservation designation.
The adverse effects of tree/shrub encroachment on grassland butterflies and Burnet moths has
been documented in Sweden where increased tree cover was associated with decreased
numbers of vascular plants and butterflies (Öckinger et al., 2006). For Forester, lack of
tree/shrub cover is important as it provides open sunny habitats together with abundant nectar
plants.
The importance of Protected sites as a factor favouring Forester offers support for the
hypothesis that suitable habitat is herb-rich as Nature Reserves are generally special herb-rich
3
places associated with high a biodiversity of both plants and animals. One of Kate Findlay’s
explanatory variables was flower density and it is interesting that Carnasserie Farm where
both the author and Findlay found three Foresters was the most flower-rich site of the 33 sites
surveyed at 16.5 flowerheads per m2 while 15 sites had values less than one. As Findlays’s
Flower variable was the mean number of flower heads (of selected known nectar plants of
Forester) per 1 m 2 quadrat averaged across 30 during a structured walk, it is probably not a
good indicator of the presence of herb-rich areas at a site which may comprise small localised
patches. It is possible as was the case with the three sites surveyed by the author that small
areas of herb-rich habitat occurred within a mosaic of habitats at the 33 sites.
Further evidence of the importance of herb-richness to Forester is provided by a study of
specialist moths in the Brecklands (Hearle & Ellis, 2012). The study investigated the effects
of different methods of creating bare ground on a range of specialist moths including
Forester. Forester was attracted to the abundant nectar that appeared on many plots and was
found on 20% of plots created.
The fact that Forester occurs at some Transparent Burnet sites also supports the argument that
Forester needs herb-rich habitats as surveys in 2013 found Transparent Burnet sites on
mainland Argyll to be herb-rich (Masterman, 2013).
Summary of known habitat requirements of Forester
The main conclusion of the author’s research to date is that Forester inhabits herb-rich sites
with abundant nectar plants. What little has been written on Forester does tend to use the
adjective “damp” rather than “wet” to describe its grassland habitat and success in
characterising its habitat might depend on being able to differentiate meadows and other sites
such as lower slopes of escarpments and stream edges which are damp rather than wet.
Common Sorrel and Ragged Robin may be less abundant in such damp habitats than in wet
examples and this characteristic could be key in identifying sites with suitable habitat for
Forester.
Of course, finding larvae would be the ultimate proof of Forester habitat requirements but
this is apparently difficult. The photo below shows a fully-grown Forester caterpillar reared
by Roy Leverton and searches on Common Sorrel in late April/early May could yield similar
caterpillars. A more practical approach is to continue to record site and vegetation data
within a 5m radius of an adult Forester observation to build a database of Forester site
characteristics. The survey pro-forma has been improved to include a soil moisture category
of damp and a score for slope and aspect.
Another approach is to test hypotheses about topographical features favouring Forester by
locating such features near to historical Forester records and searching for Forester at these
sites.

Lower parts of steep escarpments like at Carnasserie Farm and at Transparent Burnet
sites

Edges of streams which tend to be both damp and herb-rich
4

Slightly raised drier herb-rich areas in wet meadows with rank Common Sorrel and
Ragged Robin.
It might be the case that Forester is quite common in coastal Argyll if you know where to
look. It is not very conspicuous like Transparent Burnet and you will have little chance of
noticing it unless you are within a few metres of one. But with an understanding of its habitat
requirements, it might be fairly easy to identify potential new habitats and discover new sites.
Final-instar Forester larva reared by Roy Leverton.
Andrew Masterman
5
5 March 2014
References
Findlay, K., 2013. Habitat requirements of the Forester moth (Adscita statices). Unpublished
MSc Thesis to University of Kent.
Hearle, S and Ellis, S. 2012. Specialist moths in Breckland: creating bare ground habitat on
landscape-scale. Landscape-scale conservation for butterflies and moths. Butterfly
Conservation, Dorset, UK.
Heath, J. and Emmett, A. M., 1985. The Moths and Butterflies of Great Britain and Ireland,
Vol 2. Harley Books.
Masterman, A., 2013. Transparent Burnet Surveys in Argyll in 2013. Unpublished Report to
Butterfly Conservation.
Öckinger, E., Eriksson, A. K. and Smith, H. G., 2006. Effects of grassland abandonment,
restoration and management on butterflies and vascular plants. Biological Conservation
133:291–300
South, R. 1980. The moths of the British Isles. Frederick Warne & Co Ltd.
Waring, P. and Townsend, M., 2003. Field Guide to the Moths of Great Britain and Ireland.
British Wildlife Publishing.
6
Table of all Forester records in the VC98 moth database ordered chronologically
Site
Gridref
Quantity
Date
Recorder
Method
Stage
Argyll>Loch Craignish>Eilean Righ
NM8001
0
1899
Tutt
Unknown
Not recorded
Argyll>Oban>Loch Nell
NM8927
0
1899
Tutt
Unknown
Not recorded
Argyll>Oban>Upper Soroba
NM8627
0
1960
Pelham-Clinton, E.C.
Unknown
Not recorded
Argyll>Seil
NM760180
0
1960
Pelham-Clinton, EC
Field record/ observation
Adult
Argyll>Loch Feochan>Minard>Ardentallan
NM822236
0
1975
Langmaid, Dr J.
Unknown
Not recorded
Argyll>Oban>Minard>Ardentallan
NM8223
0
1978
Langmaid, J. & Agassiz, D.
Field Record
Adult
Argyll>Seil>Ballachuan
NM756146
0
1990
Young, Dr M.
Unknown
Not recorded
Argyll>Seil>Ballachuan
NM761146
0
1995
Christie, I.
Unknown
Not recorded
Argyll>Seil>Ballachuan
NM760148
0
1995
Barbour, Dr D.
Unknown
Not recorded
Argyll>Kilmichael Glen>Creag Bhreac
NR884967
1
2009
Corinne Mills
field observation
Adult
Argyll>Seil
NM760180
0
24-Jun-47
Downes
Field record/ observation
Adult
Argyll>Oban>Kilbride
NM8525
4
15-Jun-57
Pelham-Clinton, E.C.
Daytime observation
Adult
Argyll>Oban>Upper Soroba
NM864270
0
15-Jun-57
Pelham-Clinton, E.C.
Unknown
Not recorded
Argyll>Seil
NM7514
0
14-Jul-63
Pelham-Clinton, EC
Field record/ observation
Adult
Argyll>Seil>Druim Buidhe
NM7518
1
14-Jul-63
Pelham-Clinton, E.C.
Daytime observation
Adult
Argyll>Oban>Kilbride
NM8525 ?
14
24-Jun-78
Clifford Edwards
Field Observation
Adult
Argyll>Oban>Kilbride
NM8525 ?
1
27-Jun-79
Clifford Edwards
Field Observation
Adult
Argyll>Oban>Druim Mor
NM8428
1
08-Jun-82
Clifford Edwards
Field Observation
Adult
Argyll>Kilmartin>Carnassarie
NM8401
0
07-Jun-84
Raymond, J.
Unknown
Not recorded
Argyll>Seil>Loch Seil
NM801198
0
27-Jun-84
Wormell, Mr P.
Unknown
Not recorded
Argyll>Connel>Achnacloich
NM956330
0
01-Jun-86
Barbour, Dr D.
Unknown
Not recorded
Argyll>Connel>Achnacloich
NM956330
0
01-Jul-97
David Barbour
Field record / observation
Not recorded
Argyll>Seil>Loch Seil
NM801199
7
07-Jun-04
John Knowler
Field record / observation
Not recorded
Argyll>Oban>Barndromin
NM842228
1
22-Jun-04
Jamie Mellor
Not recorded
Adult
Argyll>Loch Feochan>Moleigh>Kilmore
NM878262
10
01-Jun-06
Pete Hardy
Not recorded
Adult
Argyll>Connel>Ardnaskie
NM964330
0
01-Jun-06
Bob Black
Not recorded
Adult
Argyll>Seil>Loch Seil
NM801199
8
01-Jun-08
Bill Jackson
Field Observation
Adult
7
Argyll>Oban>Barndromin
NM842226
2
03-Jun-08
Andrew Masterman
8. On vegetation
Adult
Argyll>Scarba
NM730042
1
13-Jun-08
Stephen Mason
Field Observation
Adult
Argyll>Kilmartin
NR84009901
1
23-Jun-08
Carl Farmer
Field Observation
Adult
Argyll>Oban>Kilninver
NM8419
1
13-Jun-10
Clive Craik
Field Observation
Adult
Oban>Druim Mor
NM848286
1
19-Jun-10
Steve Murphy
Field Observation
Adult
Argyll>Seil>Ballachuan
NM76071499
1
20-Jun-10
Carl Farmer & Scottish Wildlife Trust
Field record / observation
Adult
Argyll>Oban>Lochan a'Bhuilg Bhith, nr
NM87632790
1
26-Jun-10
Carl Farmer
Field record / observation
Adult
Argyll>Kilmartin>Carnassarie Farm
NM83870111
2
27-Jun-10
Prescott Tom, Leverton Roy & Huff Amy et al
field observation
Adult
Argyll>Kilmartin>Carnassarie Farm
NM838012
2
27-Jun-10
Prescott Tom, Leverton Roy & Huff Amy et al
field observation
Adult
Argyll>Kilmartin>Carnassarie
NM82790190
1
20-Jul-10
Carl Farmer
Field record / observation
Adult
Argyll>Glen Feochan>Dun Ladain Fort
NM911240
1
06-Jul-11
Zoe Clelland
Field Record
Adult
Argyll>Glen Feochan>Dun Ladain Fort
NM9112524031
2
16-Jun-13
Kate Findley
Field Record
Adult
Argyll>Taynuilt>Ardnaskie Wood
NM9674933030
1
16-Jun-13
Ian McPherson
Field Observation
Adult
Argyll>Ardfern>Craignish Castle
NM768025
1
17-Jun-13
Simon Gregory
Field Observation
Adult
Argyll>Ardfern>Craignish Castle
NM775019
1
17-Jun-13
Simon Gregory
Field Observation
Adult
Argyll>Loch Feochan>Barndromin
NM8441722660
1
19-Jun-13
Kate Findley
Field Record
Adult
Argyll>Kilmartin>Carnasserie Farm
NM8366901122
2
19-Jun-13
Kate Findley
Field Record
Adult
Argyll>Kilmartin>Carnasserie Farm
NM8402601041
1
19-Jun-13
Kate Findley
Field Record
Adult
Argyll>Ardfern>Craignish Castle
NM7757301942
1
24-Jun-13
Andrew Masterman
Field Observation
Adult
Argyll>Ardfern>Craignish Castle
NM7757501944
1
24-Jun-13
Andrew Masterman
Field Observation
Adult
Argyll>Kilmartin>Carnassarie Farm
NM8418101484
1
24-Jun-13
Andrew Masterman
Field Observation
Adult
Argyll>Kilmartin>Carnassarie Farm
NM8418401504
1
24-Jun-13
Andrew Masterman
Field Observation
Adult
Argyll>Kilmartin>Carnassarie Farm
NM8422001478
1
24-Jun-13
Andrew Masterman
Field Observation
Adult
Argyll>Loch Feochan>Barndromin
NM8597223046
1
26-Jun-13
Jamie Mellor
Field Observation
Adult
Argyll>Ardfern>Craignish Castle
NM776022
2
07-Jul-13
Simon Gregory
Field Observation
Adult
8