Species Account

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Summary Data

Season (Adult / Immature):

National Status: Local

Local Status: Scarce and local resident.

Local Record: Grade 3   See here for explanation

Flight time: One generation, Aug-Sep.

Forewing: 13-17mm.

Foodplant: Wavy Hair-grass and Tufted Hair-grass.

Regional breakdown:

Year first recorded20101900187719451927
Year last recorded20142014201220142007
Number of records510939774
Number of individuals61861932002
Unique positions25013444
Unique locations25113424
Adult records510620743
Immature records001700

For the county, we have a total of 234 records from 112 sites. First recorded in 1877.


73.061 Anomalous 2020 map
© C H Fletcher
73.061 Anomalous 02
© Damian Money
73.061 Anomalous 01
© Terry Box, 2 Sep 2011

Species Account

Sutton & Beaumont, 1989: A mainly northern and western species associated with moorland, or at least, moorland edge. This moth is very local in the centre and east of the country. In Yorkshire it has recently become more frequent.

Argus 50, 2005:
VC64. Headingley, 21.7.2003 (JKB). NEW VICE-COUNTY RECORD.

2012 (CHF): We now have records from all five five counties. This moorland moth is found in the western uplands of the county and eastern areas of VC62 extending down into the north of VC61. There have been increasing records in the last few years.

2020 (CHF):Anomalous was a rare moth in Porritt’s time. He noted “I have only seen one Yorkshire specimen; it was taken by JW Carter at Bradford on August 9th, 1877. He subsequently documented moths from Great Ayton in 1903, Ingleby Greenhow in 1900, and said it was taken “commonly near Saltaire”. By the time of Sutton and Beaumont (1989) it was “very local in the centre and east of the county and has recently become more frequent”. A slightly curious statement as records were from western areas and the north east. Since the turn of the century, we have had a steady trickle of records from western upland parts of the county and from the east of VC62, and seem to have healthy populations in these areas. Since 2010, VC62 records have spilled over into the very north of VC61 and it has become regular at Hunmanby Gap. The rogue dot in the south of VC63 is an odd record from Rotherham in 1976.

This is a moth of upland grassland and moorland where the larva feed on Deschampsia species, Tufted and Wavy Hair-grass. Tufted Hair-grass is common over much of the county but Wavy Hair-grass is much less common in the south-east of the county as it is more of an upland grass. I wonder if this is the main food plant as its distribution appears to mirror the distribution of the moth better. Moth'ers in Calderdale are particularly proficient in finding larvae and these have nearly all been on Wavy Hair-grass though there is one mention of Purple Moor-grass Molinia.

There have been fairly small numbers of records in recent years but 2020 was far more interesting. We received 23 records from 16 sites which is a very healthy total. In addition to moths from the usual areas, there were two extremely unusual records. Firstly, a moth was caught at light at Kilnwick in the middle of VC61 on 6th August. This is almost 20 miles from the nearest record. Was this just a wandering moth? Does it really occur somewhere in the area? Is there some suitable habitat we are not aware of in the vicinity? It is not usually thought of as being a migrant so it is not likely to have come too far. Secondly another moth was caught at Haxby on 15th August. This site regularly attracts wandering moths from Strensall Common which is not too far away. In some parts of its range for example Dorset, it occurs on lowland heaths. Do we have an undiscovered population at Strensall or indeed on any of our other lowland heaths? Perhaps after all, it is an unknown migrant and this is analogous to the odd influx of Light Knot-grass to lowland areas in 2019. The situation in Yorkshire shows stable numbers since at least as far back as 1995 so is at variance with comments in the recent Atlas which notes “Since 1970 it has undergone severe, ongoing decreases in abundance and distribution”. What is happening in Yorkshire? Wait for next year’s exciting episode.

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