Season (Adult / Immature):
National Status: Local
Local Status: Scarce and local resident.
Local Record: Grade 3 See here for explanation
Flight time: One generation, May-Jul.
Foodplant: Common Reed.
|Year first recorded||1929||1991||1962||1988||2014|
|Year last recorded||2014||2014||2014||2014||2014|
|Number of records||165||9||40||20||1|
|Number of individuals||173||15||122||24||1|
For the county, we have a total of 235 records from 60 sites. First recorded in 1929.
Sutton & Beaumont, 1989: Very local in reed-beds. Until 1970 there were only two known localities for this species, Skipwith Common (VC61) and Thorne Moors (VC63). In the last few years it has been recorded from many new sites. However, it has been suggested (PQW pers. comm.) that people have been searching in more inaccessible areas (in terms of light trapping) and finding already established colonies rather than the species actually spreading.
2012 (CHF): There have been several more sites for this species and it does genuinely appear to have altered its distribution in the county. Records are now very rare in VC63 whereas it has spread in other areas as far north as Teesside - the most northerly site in the country. Numbers in VC61 have increased considerably and since 2006 it has appeared at three sites in the Ripon area. In the last two years numbers of records have shot up to 15 in 2010 and 29 in 2011.
2020 (CHF): What is happening to Obscure Wainscot? It’s another ditherer. It can’t make up its mind what it’s doing. It’s obviously friends with Pine Hawk-moth. Looking at the records/year graph, it looks like the Alps. I don’t like graphs like this. I like a moth that knows if it’s increasing or decreasing. If you try and put a trend line on this sort of data you are in danger of getting a sarcastic message from Excel along the lines of “are you sure you want to do this?” Looking at the Rothamsted web site they don’t comment on it. Perhaps the data froze their computer. The Atlas doesn’t try to tell us if the abundance is going up or down. I don’t blame it in the slightest. In Yorkshire, ten years ago, records had sunk so low it had almost disappeared, then it staged a major revival with good numbers in 2017/8/9. In 2020 it slumped dramatically. Interestingly, another reed-feeder, Silky Wainscot did the same in 2020 so I’ve included the chart for a bit of comparison.
The distribution maps are equally odd. It has increased in range – considerably, but on the other hand it has completely deserted East Anglia. It doesn’t like Lincolnshire either. What’s it all about? Do they have the wrong flavour reeds? There is certainly no lack of reeds in Norfolk so it isn’t loss of habitat. It’s so rare there now that they ask for a photo or specimen to back up any record.
It is a relatively new addition to the Yorkshire fauna. Porritt never saw a Yorkshire specimen. The first one was at Skipwith Common in 1957 where it became fairly common for the next few years. Thorne Moors had moths from 1962 and by 1970 there were records from Muston and a decent colony built up at Spurn. Other sites followed, but Sutton and Beaumont’s comments that it was “very local in reed beds” in 1989 seems a good summary. A decline to no records at all in 2001 and 2002 was followed by an expansion of range and it reached my area in 2006 where it remained very local. It reached Teesside in 2011 and by 2019 it had been seen at lots of widespread sites in the centre and east of the county. It had even got to the south of Northumberland. But in 2020 in Yorkshire, there were a mere 16 records of 45 moths from 11 sites; a huge drop. Apart from 25 in one session at Skerne Wetlands, all the others were of very small numbers.
Obscure Wainscot is capable of appearing in large numbers when it wants to. Blacktoft Sands has regularly attracted counts of 20 to 40. We had never encountered it at Nosterfield NR until 1/7/15 when we put some traps in the reed bed there and caught 81: a total which has never been beaten in the county. There have only been small numbers since. It is meant to be a sedentary inhabitant of reed beds but it does turn up in odd places. I’ve had it in my garden in 2017 and 19 and have yet to plant my extensive reed bed!
So, what is the cause of this odd behaviour. It over-winters as a larva in stems of common reed. Do they manage reed beds differently in the Broads? The way it moves to a new area, rapidly builds up numbers, then falls of a cliff edge can’t be due to habitat or climatic change, so is it parasitoids at work? I get the impression that there is a lot that we don’t know about this species. Noctuidae Europaeae intriguingly says “at times may be common” which suggests to me that population fluctuations have been noticed elsewhere.
I would love to tell you that it’s scientific name obsoleta reflects its tendency to render itself obsolete at times, but I’m afraid it’s the same as the vernacular epithet, “obscure”, referring to its undeveloped markings. I find this one of the easier Wainscots to identify. It’s obviously different when you have one in the hand.