19-Aug Moths of a Summer Night

August is an especially good month to see thorns, rustics, wainscots, prominents and hooktips as well as the more typical carpets and pugs. The larger moths seen tend to be the ubiquitous yellow underwings. As there are so many noctuids and geometrids and as they have such similar markings, field identification of these groups is difficult. It is made even more difficult by the endless variants and melanistic forms. However, for anyone interested in different shades of grey, brown and yellow the month is a very exciting one. Other than parks and gardens good places to visit, especially in moonlight, are downland, cemeteries, wasteland areas and the wilder edges of the lower Thames.

Most Londoners have encountered a large, brown moth which, when disturbed, flashed a yellow underwing. This is likely to have been the Large yellow underwing which some say is the most common moth in London. It often runs away rather than flies and if it does take to the wing it tends to fly low and not too far. There are, in fact, four other yellow underwings, all of which are widespread. They all differ in size with the Least yellow underwing being the smallest as well as the least common. The Broad-bordered yellow underwing is probably the easiest to identify due to the broad black band across its yellow hindwings.

The star among this group and one of the most special moths of the month is the Red underwing. This is a very large moth with fine zigzag markings on its forewings and wine red hindwings neatly bordered in black. In the past it was so highly sought after by collectors they were encouraged to buy their specimens from Germany or France to protect our native population. Fortunately, it is now both reasonably common and widely distributed and is occasionally even seen resting on walls during the day or visiting Buddleia bushes at dusk. Underwings cannot be mentioned without including what used to be called the Blue underwing but has now got the extravagant name of the Clifden Nonpareil.

This is about as large and exciting as a noctuid gets with its grey zigzag forewings and violet flash both bordered in black and fringed in white. Sadly it very rarely visits now and if it does is usually seen next month.

Another star of the month is the Black Arches which is again large and with even blacker zigzag markings, this time set off against a snow white background. Being a moth of old oak woodland it is now rare in our area but may still be found in favoured spots such as Ashstead Common.

There are also a number of other handsome or unusual black and white species, most notably the Four-spotted, Scarce dagger, Black-banded, Willow beauty and Lime-speck pug. There are also always moths that have English names that may help slightly in a field identification. This month’s candidates, which are all shades of brown, include the Dotted clay, Nutmeg, Belted chestnut, Dun bar and the Brick. One common moth which is also common across the whole of Europe is the Flame shoulder. This is easily recognised, especially at rest, due to its straw-coloured shoulders or ‘flames’. If disturbed it is well known for having a particularly wild way of flying. Another moth that stands out is the Lace border. As its name suggests it has delicate markings and is the shape of an Elizabethan lace neckpiece when seen at rest. You can sometimes put them up during the day walking along the North downs. Other moths easily disturbed in more grassy areas are the Treble-bar and the Knotgrass.

Rarely, numbers of Vestal moths are seen flying over wheat fields. They have lemon wings, occasionally suffused in pink with a fine pink line across them. The similar Blood vein is seen in gardens. Its pink line crosses cream coloured wings with a pink fringe.