Moth Trapping in Wanstead Park

The local Wren Conservation Group held a moth-trapping evening in Wanstead Park on 24th September. It was attended by ten Wren Group members, including myself, and four people with a range of moth-trapping identification skills who brought five moth-traps along.

Tim Harris organised this, with the co-operation of the City of London Corporation, as the event was held in and adjacent to the Temple at Wanstead Park. Forest Keeper Brian Gotts was kind enough to open up the Temple for us to plug in the lamps that attract the moths and to give provisions for those present to try to identify the catch around a table in the Temple.

There are a range of ways that moths can be attracted, and the most well-known of these is by light. Even an electric light and an open window can provide a good supply, as may be well known! However, moths are more attracted to certain wavelengths of light, and the appropriate light source can have a considerable effect on the numbers and even the species attracted. Having been attracted, the traps themselves can vary greatly. The traps used on the evening were Robinson Traps and Skinner Traps, and the lamps were very bright Mercury Vapour types.

It should be emphasised that the moths are trapped live, and can be released unharmed afterwards. The lamps attract them, they make their way into a container - or even simply onto a sheet so that they can be seen - and then can be removed in individual clear plastic containers to be examined and identified. To make things more homely for them whilst they are in the traps, egg-boxes are laid out which they can cling to and hide out in the crevasses.

Hornet

One of our first catches was not a moth but a Hornet. Other creatures are of course attracted to the lights, and these included a Frog-hopper and some Caddis Flies. The Hornet was quite a large one - and one of many that have been around Wanstead Park in recent months. Although they are often feared, this member of the wasp family is actually one of the less aggressive wasps and its sting is said to be not much different from that of the common wasp. Nevertheless...

Very few moths were caught, however, between setting up the traps at about 7.30 and finishing at about 10pm. As with all wildlife, it's not always easy to predict what will happen. The night was relatively clear - with Jupiter and quite a few stars shining - bats were flying, but we noticed the first "huffs" from our breaths of the season. Maybe it could have been just a bit warmer to have produced more of a moth-catch, but it didn't actually feel particularly cold.

Lunar UnderwingA good collection of moth-identification guides were available, brought by the experts and provided by some of the local naturalists, and some moths were available early on, brought from Epping. The guide that I like to use is the "Field Guide to the Moths of Great Britain and Ireland" by Waring, Townsend and Lewington. This has illustrations of all the resident and migrant macro-moths (the larger ones as opposed to the usually tiny "micros"), showing the moths in typical pose and at life-size. This helps a lot in visually identifying species, and reference to the text then can help clarify the identification.

With a bit of help at times from those who were more knowledgeable, all of the macro moths were identified including those that were caught locally. The latter were Lunar Underwing, Willow Beauty, Pale Mottled Willow, Brindled Green and Square-spot Rustic. Two "micros" were taken away for expert identification, and it is hoped that we may find out what these were to supplement local records.

Willow BeautySome years ago I set out a moth trap in my garden by Wanstead Flats. This was a "Heath" type trap, with an Actinic (fluorescent) lamp of much less intensity than the mercury vapour ones. (It's more friendly to the neighbours!). In the course of the two seasons that I set the trap nightly, some175 species were identified. For a review of this exercise, click here

Thanks to Tim Harris for organising this, to the Conservators of Epping Forest for allowing us to use the Temple and Wanstead Park, to Brian Gotts for opening and closing the Temple for us, and to Anthony and Pat Harbott, Grahame Smith, and Martin who gave us their time and expertise.

Paul Ferris, 25th September 2011