Yorkshire Status: Rare and local resident.

Sutton & Beaumont, 1989: Only recorded from the west of VC64 in recent years but from Skinner's (1984) account it should be much more frequent.

2012 (CHF): Most of our recent records come from ash woodland in upland calcareous areas in the west of VC64 and 65 where this species is local but not uncommon. It has not been recorded in VC62 or 63 for many years. In 2010 it appeared at Spurn and there were several more records here in 2011. It is likely that these have come from an expanding population in Lincolnshire and it will be interesting to follow the distribution in the next few years.

2020 (CHF): Porritt described Coronet as "local" at the end of the 19th century but was aware of records in all five VCs. The north-west of the county was probably the best area however and he found "larvae common on ash at Leyburn" in 1900. It seems to have hung on in upland parts of VC62 and on the Wolds in VC61 until the 1960s before becoming confined to ash woodland over a wide area in the western half of VC64 and 65 where the population has remained stable for many years.

In other parts of the country, it has a rather patchy distribution but in recent years has been moving into new areas. In the early 2000s, numbers gradually built up in counties to our south and east - Lincolnshire and Nottinghamshire. Then in 2010 single moths were seen at Spurn on three occasions in July. Every year since we have had more records and it has been slowly and gradually extending its range north and west, on average about 5-10 miles per year, though a couple of years showed no increase. This year, numbers of the old native population are stable with 16 records of 18 moths from the usual areas, as far south-east as Burley-in-Wharfedale. Numbers of the new invaders have rocketed - 138 records of 208 moths is by far the most we have received. The range has again inched forward a few miles and new sites on the frontier include the Lower Derwent Valley and Kirk Smeaton. The two populations are now about 25 miles apart at the nearest point. If the rate of advance continues at the same rate, the populations may well join up in about five years. It all rather reminds me of Vikings advancing into Anglo-Saxon territory, or have I been watching too much Vikings on Amazon Prime?

This raises some interesting questions. What is going to happen when the populations meet, if indeed they do? The two populations have been reproductively isolated probably for over 100 years. Will there be genetic differences and what will their effect be? Will the invaders being new diseases or specific parasitoids that the native population will be unable to cope with, or will the opposite be true and the newcomers will succumb? Will interbreeding bring hybrid vigour so that the forces join up and invade new territories? Will the invaders adapt better or worse to ash woods in the Dales? What will be the effect of ash dieback on either population? Are the new invaders adapted to feeding on other trees rather than just ash? In parts of the country Coronet apparently uses alder and hazel. The only two larval records on our database are Porritt's old record from Leyburn and one from Grass Wood many years ago, so are we correct in assuming that it just uses ash here? Will the two populations remain separate so we are left with "upland" Coronets and "lowland" coronets. So many questions!

Recorded in 91 (46%) of 200 10k Squares. First Recorded in 1883. Last Recorded in 2022. Additional Stats

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