Darter Days

A characteristic sight of the Northamptonshire countryside during the days of late Summer and Autumn are the two species of darter dragonflies. Although the first individuals can emerge as early as June they do not appear to reach their peak numbers until August. I often struggle to separate the two, particularly at the beginning of the season and thought I would share my meagre store of knowledge just in case you find one and wonder what it is.

Male Ruddy

Male Common. Most of the difference between the species can be seen in the two photographs. The paler red colour of the Common in contrast to the darker red of the Ruddy, the bi-coloured eyes and the paler thorax sides showing stripes. Also note the all black legs on the Ruddy.

Both darters are smaller than the other species of dragonfly, some Ruddy Darters can appear very small indeed while the largest Commons can approach the chasers in size. From my experience there seems to be quite a lot of overlap so although size can be useful, particularly in direct comparison, it is by no means a clincher.

Young male Ruddy, more of a challenge but the black legs are diagnostic.

A young male Common.

Rather fortunately for the would be darter diviner these two species seem very partial to a spot of sun bathing and even the ones that zoom off often return to the same favoured spots. A pair of binoculars can be useful, especially with the females and a digital camera can be a boon. Ruddy males when seen well are quite distinctive, they're a lovely deep shade of red and appear to be rather wasp waisted. Male Commons are a paler red and are only slightly waspish in the waist department. The eyes of male Ruddies are all over red whereas male Commons have two-coloured eyes. Another feature shown by Commons is the stripes on the sides of the thorax which don't appear to show on fully adult Ruddies.

Female Ruddy

Female Common

Females and immature males are even more of a challenge but happily there is one silver bullet that should clinch an I.D. While in normal circumstances it might be considered rude to peer too intently at a lady's legs with the darters it can be essential. Ruddy Darters show all black legs while Commons show some yellow, on younger specimens they can appear very pale. One thing I've noticed though I can't be sure at this stage whether it amounts to much is that mature female can become a dull olive colour with a bluish underside. I have not seen female Ruddies showing this colouration but that doesn't mean that they don't, I'll let you know if the situation changes.

A more mature female Common Darter.

While both species are amongst the last of the dragonflies to disappear it is Commons that linger longest, I've seen them in November while there are December records in more southern counties. If you're out on a sunny day over the next couple of months it's worth sparing a few minutes to look out for them, a last taste of Summer before the winter chills take over!

Of course if you're confident at separating the males then the females can be more straightforward in some circumstances!