Odonata. Odo- what? In ancient Greek it means 'toothed jaw', and this is the name under which dragonflies and damselflies are grouped and the name comes from the fact that their mouth parts are serated.
Dragonflies and damselflies are on the wing from May to September with a small number of species on the wing into October and November. In the UK 52 species of odonata have been recorded with 38 of these breeding in the UK. The rest of the records are of species which have either become extinct in the UK in the last 50 years or are migrant species such as the Vagrant Emperor. Many species with a primarily Mediterranean distribution in Europe are known to now be advancing northwards, possibly related to climate change. And there's one species, the Highland Darter, which is thought not to be a seperate species at all but a dark morph of the Common Darter.
Southern Migrant Hawker
Identifying dragonflies in the field can take some practice, particularly with something like the hawkers which settle infrequently. Taking in fight style, habitat, colour and markings can help. Males tend to be more brightly coloured then the females - it all sounds a bit like birds. Damselflies and dragonflies are fairly obviously told apart with damselflies generally being smaller with a weaker flight. At rest, dragonflies will hold their wings open whilst damselflies usually hold their wings shut. Another difference is that damselfly eyes are proportionally much smaller than dragonflies, which have massive compound eyes, giving them 360 degree vision that enables them to detect the smallest of movements from a distance.
Common Hawker, photo courtesy of Ken Gartside
That's nothing compared to their flight. These are insects that can beat their two sets of wings out of phase, hover and fly backwards and sideways. And they can fly fast - the maximum speed of large species like the hawkers is around 25-30 mph, although average cruising speed is probably about 10 mph. Dragonflies can make rapid changes of direction, making them fantastic aerial predators, feeding on everything from small midges to butterflies. A dragonfly's legs have rows of sharp spines which help trap prey, often consuming it in flight. And dragonflies themselves are prey for birds such as Hobby and Tern. I recently watched a fantastic aerial chase between a Common Tern and a dragonfly with the tern finally catching the dragonfly.
The British Dragonfly Society says that over a third of the UK's breeding dragonfly and damselfly species are in decline. Some of this is due to changes in agriculture through, for example, the loss of ponds that were once used to water livestock. As much as 95% of the life cycle of a dragonfly is spent under water, so garden ponds can be important habitat for dragonflies and it's just one reason why we create ponds as part of our woodland management work at Dove Stone.
Broad bodied chaser photo courtesy of Ken Gartside
So what of dragonflies at Dove Stone ? With hawkers we've seen recently Brown Hawker, Common Hawker (including ones egg laying ) and Southern Hawker, whose distribution is more lowland and southern, which makes this a good spot ! There's also been Broad Bodied Chasers at our woodland pools. With damselflies we've recent sightings of Large Reds, Azure damselfly, Blue tailed damselfly and Common blue. Thanks to Ken for keeping the records and photos coming. However, some of the UK's dragonflies aren't doing so well due to habitat loss and, here's the link, this is particularly affecting bog-loving dragonflies such as the White-faced darter.
Blue tailed damselflies, photo courtesy of Ken Gartside.
The White-faced darter is one of Britain's rarest dragonflies and has been found to breed at only five sites in England, including upland bogs, and it certainly used to be found in the north-west. It's habitat is one of acidic water ( which doesn't support predators such as fish ) and the larvae of the White-faced darter live amongst Sphagnum moss. Re-colonising Sphagnum moss is a big element of our blanket bog restoration work at Dove Stone. Who knows, maybe one day we'll have White-faced darter to add to our records !
More soon with an update of Dove Stone's 2013 bird list and a bit about moths, ahead of this weekend's National Moth Night.