Monday 11 July 2022

Moth ID - First Steps

Having made the decision to get involved with moths, it has been interesting to embark on an identification journey that is almost from scratch. Presumably I did something similar with birds once, but it is so long ago that I can recall very little of it. With moths though, I've been taking mental notes of the process...

Here is our moth library...

The books at left and top centre we have owned since the 1980s; right and bottom centre are the new additions.

The older books are typical of the day, with colour photos of pinned specimens. Armed with these, we would tackle any new moth that had settled by our porch light, and do the best we could. Leafing through the plates, aiming to match a live moth with a crispy, mounted one became a regular summer morning's pastime. Then there would be reference to the text for additional information, sometimes a useful illustration of diagnostic features on tricky species, etc, before a verdict was reached. We had no impartial verifier to offer advice, to confirm (or refute) the ID, nor any idea of a record's context. We were, in effect, on our own.

Thirty-five years on, things could not be more different...

The new books are amazing. Manley is all photos of moths at rest, usually in similar attitudes for ease of comparison. Waring et al features the astonishing colour illustrations of Richard Lewington; again the moths are at rest, as you would see them in life. Both have been invaluable. So, that's the books. An improvement on Skinner and Goater, certainly as far as leafing through the plates and trying to match a live moth with a picture is concerned anyway.

And that last point is an important consideration, I would say. Because, faced with a new moth, what do you do? You flick through the pictures, looking for a match. Simple. When almost every moth is new, it can take ages. Soon you learn which plates to head for first, which speeds things up a bit, but even now, five or six weeks in, it can seem quite laborious on occasion.

On the up-side, I am building a repertoire of familiar moths, moths that I can do at a glance. And that feels great.

However, the biggest improvement in ID resources has nothing to do with books, and everything to do with digital technology. Photography and the internet have been a game-changer. The ability to punt out a photo on Twitter for example, and get umpteen skilled, experienced moth-ers on the case. Or the many excellent moth web sites out there, filled with superb images and ID tips. And then there is artificial intelligence. The ObsIdentify app will analyse your photo and offer an ID, complete with percentage confidence rating. How it does this I have no idea. It blows my mind...

Personally I dislike needing to ask someone else to ID a moth for me. I would much rather do it myself, and then seek confirmation if appropriate. However, sometimes I am stumped. Like this morning...

Last night, while out with the trap, I potted a pug on the cabin wall. I wrote 'Common Pug?'. For some reason I wasn't happy with it, hence the question mark. This morning I took a pot-shot...

Pug sp.

A couple of things bothered me. Wing shape looked a bit broad, no white spots where there ought to be, etc, etc... Lazily, I decided to try ObsIdentify first. The verdict was rapid: 'Plain Pug', it said, '100%'. No ifs or buts. I checked the books and multiple online photographic resources. No doubt about it, this very un-plain pug was indeed a Plain Pug. Dorset records do not seem to be that numerous (less than a handful in the Bridport area this century) so this is a nice catch. A better photo...

My first Plain Pug

I know from birding that the more familiar you become with everyday species, the more likely it is that you will spot a new one, even when differences are subtle. And with moths, subtle is everywhere.

I wonder if I will look back at this post in a year's time and smile at its naivety? Ah well, when it comes to moths, I am almost as naive as they come. So yes, probably I will.


  1. On my third full year of trapping, plus most of the latter half of 2019. It's surprising how quickly you do learn the regulars - although some are still having to be re-learned each year! Confidence in ID'ing some of those species pairs, or even triples, is a long time coming in some cases. Micros are a whole other game, all those aggs and generic sp. IDs don't really sit well with me. However, I'll live with it for now as I'm not prepared to 'take' a specimen for gen.det. Steep learning curve... and all those Latin names 😯

    1. I've heard about the 're-learning' thing! Aggs etc do go against the grain a bit, but, like you, I'm not so concerned about specific ID that I need to go further than a good, hard look. 😊
      Nice to hear the experiences of others. Thanks for your comment. 👍

  2. I had my first Plain Pug yesterday too Gav, scarce up here...