What to look out for in Early August
30/07/2023
Most of our damselfly species will be past their peak in terms of numbers, although the majority will still be found, albeit in smaller numbers. However, August is when two of our damselfly species will be reaching their peak. The first is Small Red-eyed Damselfly, which first occurred in Britain in 1999 and is now found in much of Southern Britain. It is still expanding its range so may well be found at new sites. It is similar to Red-eyed Damselfly, which is a well-established resident, and both species tend to perch on floating or emergent vegetation out on the water and are difficult to find on bankside vegetation. The key to separating the two species is to check the area of blue at the end of the abdomen in the male. Red-eyed Damselfly has a band of blue, while in Small Red-eyed Damselfly has blue sides to the abdomen at both the front and rear. With experience, this can be spotted fairly readily, although binoculars, or a camera, can help, due to the fact that the damselflies tend to be at some distance.
The other damselfly species reaching peak numbers is Willow Emerald Damselfly. This is another new colonist, but first arrived in the country a decade later than Small Red-eyed Damselfly and is still in a rapid range expansion phase. A damselfly hanging vertically from a branch on a tree or shrub is worth a second look and with several species of emerald damselflies now occurring in Britain, the key feature to check is the colour of the pterostigma, the wing spots, which is very pale and outlined with black in this species.
Migrant Hawker is the last of the large hawker dragonflies to emerge and while the first have been seen in July, it is August before large numbers emerge. This is the only one of the Hawkers to congregate together in numbers; other species tend to be territorial and chase off others of their kind, but Migrant Hawkers will fly and roost together and seeing several together is a good pointer towards identification. They are most likely to be found in the same areas as Southern Hawker and can be distinguished by being a little smaller, lacking the very obvious pale stripes on the thorax of Southern Hawker and being blue rather than blue/green in the case of males. Migrant Hawkers tend to hover more frequently than other hawker species and can remain stationary for several seconds, making them a good subject if you want to try for flight photographs of dragonflies.
The darter dragonflies will be around in good numbers and in the case of Common and Ruddy Darter may be found well away from water and particularly along rides in woodland or areas of scrub. Immatures tend to perch on stalks to watch out for passing insects and dart out to catch them before returning to their perch. It is worth being alert to the possibility of Red-veined Darters emerging from ponds alongside the commoner species in August. This species is occurring in Britain more frequently and might be found anywhere; there have already been reports from Scotland this year. Adults arrive from the continent earlier in the year, lay their eggs and the new generation develops rapidly to emerge in the autumn. The immatures tend to be a paler sandy yellow than the commoner species, but the key identification feature is that the lower part of their eyes are blue. This obviously needs a close look to check. They are a migratory species and they seem to depart from breeding ponds soon after emerging and before they gain adult colours, probably migrating south to breed.