What with it being increasingly howlingly windy, overnight moth-trapping conditions weren't exactly propitious; however, the arrival of considerably milder air as the night went on brought with it a nice migrant moth highlight in the form of the island's tenth Silver-striped Hawkmoth © Martin Cade:
Talking of moths brings us on to another interesting subject, that of belated news of a first for Britain from the Obs garden moth-traps back in 2022. October of that year was tremendous for moth migration, with our records already including the first British mainland Southern Brindled Green (the only previous records had been from the Channel Islands) and the first British wild-caught Robust Tabby (the few previous records had all been from warehouses/shops); to these we can now add the first record of the pyralid, Evergestis isatidalis, that was trapped in the Obs garden on the night of 22nd/23rd October. At the time we'd identified the moth as the similar Cornifrons ulceratalis and it was seen alive by a good many moth twitchers and photographs were posted on the blog and reposted on various social media sites; since it was a first for Portland as well as being a good national rarity we eventually set the moth and it had languished in a store box until last weekend when Mark Parsons and Phil Sterling paid us a visit to check out some other specimens they had an interest in. With previous experience of ulceratalis, Mark spotted that our specimen didn't look right and photographed it for further investigation - this revealed it was in fact Evergestis isatidalis, a moth hitherto known only from countries bordering the Mediterranean Sea and from the Canary Islands:
At rest these two species are very variable and can look alarmingly similar: for example, check out the Lepiforum pages for each - isatidalis and ulceratalis. However, isatidalis is considerably larger than ulceratalis and, seemingly diagnostically, it always has a curved sub-median row of dark dots in the hindwing that's absent in ulceratalis. Many thanks to Mark and Phil for their help - both they and us have been extremely busy in recent years and we have literally years worth of set specimens of tentatively identified or wholly unidentified moths in store boxes for them to work through - watch this space for some more surprises like this! Photos @ Martin Cade.
The nets @portlandbirdobs.bsky.social remained firmly furled today as Storm Amy hit us with rain and gusts up to 48mph by evening.A good time to reflect on 12 brilliant days of ringing, good numbers and variety. Autumn Chiffchaffs always reflect a change of seasons and Wrynecks confirm the feeling.
— Peter J Morgan (@pbo61.bsky.social) October 3, 2025 at 7:55 PM
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