A visit to Amwell on Thursday June 25th 2015 led Graham Canny to the discovery of yet another new species of Odonata for the county - a Norfolk Hawker, also known as the Green-eyed Hawker, Anaciaeshna isosceles.
As if this wasn't enough, Graham then immediately followed this by photographing the second Scarce Chaser, Libellula fulva, to be recorded in Hertfordshire this year, a male this time.
Graham found both species in the area known as Tumbling Bay, north of the main pit overlooked by the main viewpoint on the reserve. The gravel pit here contains a wide variety of aquatic and emergent vegetation with two areas of open water separated by a band of reeds.
Neither species was identified at the time that they were seen, but the photographs that Graham took at the time left no doubt about the identifications.
Graham describes the circumstances as follows:
"The Norfolk Hawker was seen on the left-hand lagoon, initially flying back and forth, interacting with a couple of Four-spotted Chasers. There was also a Hairy dragon nearby on patrol, while an Emperor was closer, ovipositing. At first, from the colouration (yellowish-reddish), I actually thought it might be the Common Darter that Darren [Darren Bast] had seen a few days earlier. Then it landed on a reed on the opposite bank, just over from the lily-pad area. I managed to take a few shots of it, before it then took off, where I lost sight of it.
A few minutes later I moved over to the right-hand lagoon. There was only one dragon in the vicinity, which I thought was a Black-tailed Skimmer, but was, in fact, the Scarce Chaser. I managed to take loads of shots of this, as it was perched up between me and another set of lily-pads. The only other odonata about were Red-eyed, Blue-tailed and Common Blue damsels.
The weather at the time was clear-ish, sunny skies, with just a hint of a breeze. Very humid. Unfortunately, no-one else was around, apart from a woman and her bathing dog.
It was only when I arrived home and checked the photos on my laptop that I realised that my assumption of a Darter and a Skimmer was incorrect."
The following day (June 26th), at least three Norfolk Hawkers have been seen in the same area, including a mating pair, but there has not yet been any further sign of the Scarce Chaser (a mature male so, a different individual from the one photographed by Barry Reed on June 5th, which was an immature female).
Roy Woodward, Hertfordshire Dragonfly Recorder, added
"Like the Scarce Chaser, the Norfolk Hawker has been increasing found in new areas in England during recent years.
At the end of the 20th century Norfolk Hawkers in the UK were confined to east Norfolk and adjacent parts of Suffolk,but since the turn of the century they have spread further south in Suffolk and into parts of west Norfolk. At the same time populations have been established in Cambridgeshire and Kent, and wandering individuals have been seen elsewhere. Sightings at coastal localities provide good evidence that immigrants from the continent, where the species is widespread, are reaching the UK, and this is the most likely source of the very Kent population which has been establishing itself at a few site during the last few years.
We can do little more than speculate where the Amwell individuals came from, especially as the recent weather conditions have been accompanied by very little wind. It is possible that they have come from populations elsewhere in the UK, but equally possible that they are new immigrants from the continent."