A Moth Marathon at Cors Dyfi

With the weather improving and looking even better for the week ahead I decided to throw caution to the wind and do a 3 nights in a row trapping session at Cors Dyfi.

The techy bit – 4 traps in total. One sheet & 125w MV bulb above the Visitor Centre. One 125w MV Skinner in the carpark. One 125w MV Robinson halfway down the boardwalk. One 40w Actinic Funnel Trap at the end of the boardwalk. Start times around 9.30pm, finish times around 4am – I had to finish this early because the birds have learned quick and come down to peck all the moths off the sheet and from around the traps! Highest temperature recorded was 19.7 at start of trapping. Lowest was 11.1 at end of trapping.

The first night, Tuesday 24^th July remained warm and much to my surprise a lot of moths turned up! Just 2 weeks previous I was still getting averages of just 40 to 60 moths in each trap, now they’d shot up to the high hundreds – amazing what a few days of warmth and dry can do!

The second night was even warmer with temperatures out on the reserve staying in the teens, it’s always 2 or 3 degrees cooler out there than up in the carpark so this made a nice change - though of course it did mean that the mozzies were totally merciless and I ended up with several painful and swollen bites. It was worth it though to get over 700 moths recorded in one night, something not achieved since the warm spell at the end of March before temperatures plummeted. Most notable of those caught was a Lime-speck Pug, not seen in the county since 1998, and 2 Clouded Magpies. 

One of the most numerous species caught was the Garden Tiger and, whilst most were the standard dark brown with white patches type, quite a few were mostly white with dark brown, something I'd not personally seen before and which led me to wonder if this species can actually produce a pure white form and what is it that actually distinguishes pigmentation on the wings?

The final night and temperatures dropped considerably, only just over 11 degrees out on the marsh – subsequently moth numbers dropped too, though still very good at around 530 in 4 traps.

Despite the endless mozzie bites, the total exhaustion and the hours spent filling in the spreadsheet afterwards it was a very enjoyable time; over 1700 moths were logged of 134 different species and 11 new species were recorded for the reserve.

Perhaps when I’ve recovered I’ll do it again.....