Bird-dropping Tortrix moths of the British Isles. A Field Guide to the Bird-dropping mimics by Jon Clifton and Jim Wheeler

It is somewhat surprising that the burgeoning popularity of mothing, particularly amongst the birding fraternity, has not resulted in a deluge of publications to satisfy the thirst for knowledge of a new generation of enthusiasts.

Waring et al. and Skinner cover most of the bases when it comes to identifying macro moths, but for the micros it is a rather different story. The gold-standard multi-volume treatises are expensive and/or out of print and many people rely heavily on the internet or more experienced contemporaries when trying to put a name to micro moths.

Now, Jon Clifton and Jim Wheeler have produced an attractive and affordable guide that, for the bird-dropping Tortrix mimics at least, provides an excellent starting point for those who want to take their identification skills further and begin to get to grips with this difficult group.

The guide is a good-quality softback in A5 format. An introductory section explains the selection of the species covered — one person's list of what constitutes a bird-dropping mimic likely being different to another's. There is a useful explanation (by means of an interpreted photograph) of the technical terms used to describe the topology of a moth. Unless you are an expert, you will need to refer to this regularly when using the guide. The authors recommend the use of a hand lens in conjunction with the guide and emphasise that care should be used when interpreting the colours in the photographs.

The bulk of the book is taken up by the 59 species accounts, which are set to a standard format, with a photograph of the moth in its natural resting posture alongside that of a set specimen. The photographs are of good quality and sufficient size, though in my copy the resting-posture image of Apotomis lineana is underexposed (presumably a printing issue, as the same photograph on the Norfolk Moths website is much better in this respect).

The pictures of the pinned specimens are not standardised in terms of exposure but are generally taken against a neutral background. They are annotated with labels pointing to a particular diagnostic feature which is discussed in detail in the accompanying text. For me, this is the best aspect of this book — the combination of the two photographs of the moths in different postures alongside a detailed but readily understandable identification commentary.

Other features of the species accounts include details on flight periods, distribution and abundance, length and wingspan, food plants, etc. Confusion species are cross-referenced and key differentiating features explained. There is a handy thumbnail index and bibliography at the end of the guide.

The book is subtitled 'A Field Guide to the Bird-dropping Mimics'. I'm not sure how useful it will prove as a guide for actual field use, but for sitting down with a specimen and hand lens or comparing a good-quality photograph in good light at home, it will surely be useful.

So who will benefit from this guide? While it is unlikely to provide much new information to an experienced lepidopterist, anyone else who is looking to improve their identification skills and attempting to put a name to specimens they have previously sent to others will surely find it valuable. You will not be able to put a name to every bird-dropping Tortrix you come across using this guide, but you will be able to identify some of them and it will certainly help to point you in the right direction as you look to other sources. I look forward to putting it to the test over the coming months!

Clifton and Wheeler are to be congratulated for putting this book together and I for one am hopeful that it will prove successful enough to encourage further similar guides to difficult groups of species.