Green-eyed (AKA Norfolk) Hawker, Barrow Lower Lodge. It has been out for a while, with a faded isoceles triangle and some wear on its wing tips (Mike Watson)
DRAGONFLY EXCITEMENT IN THE RIBBLE VALLEY CONTINUES! Earlier this week, Mark Breaks found four Green-eyed (AKA Norfolk) Hawkers Isoaeshna isoceles at Barrow Lower Lodge, near Clitheroe. Lucky for me, one of them was still present on my local patch when I got home from Serbia today. It was interesting that it was a late riser, and was not flying when I arrived at 0830. Emperors Anax imperator dominated the scene early in the morning, when it was already over 20 degrees Celsius; the Green-eyed Hawker got going later at 1100 and was still flying at 1430. Patrolling up and down over the reeds on the south side of the lodge (it is a male), but taking photos of it was far from easy. There is so much pond weed and algae at the moment that an uncomplicated background to allow the autofocus to lock on for long enough is almost impossible. However, it eventually perched in view several times. I checked Barrow Upper Lodge too but only saw Emperors there. It was great to share the sighting with Phil and Brenda Larkin for a while, it was hard work following its movements in the heat but the effort was worthwhile in the end. There was a total of 11 species flying at Barrow Lower Lodge today, quite exceptional for such a small site in East Lancs. Common Blue Damselfly Enallagma cyathigerum, Azure Damselfly Coenagrion puella, Blue-tailed Damselfly Ishnura elegans, Large Red Damselfly Pyrrhosoma nymphula, Red-eyed Damselfly Erythromma najas, Banded Demoiselle Calopteryx splendens, Common Darter Sympetrum striolatum (teneral), Emperor Anax imperator, Brown Hawker Aeshna grandis, Green-eyed Hawker Isoaeshna isoceles & Four-spotted Chaser Libellula quadrimaculata.
Green-eyed (AKA Norfolk) Hawker, Barrow Lower Lodge (Mike Watson)
Green-eyed (AKA Norfolk) Hawker, Barrow Lower Lodge (Mike Watson)
When I first began studying dragonflies in the 1980s, the Norfolk Hawker—as it was universally known then (or simply isoceles among some older enthusiasts)—was regarded as a great East Anglian speciality. It was known only from Norfolk and a tiny area of north Suffolk bordering the Broads. During the 1990s, I regularly saw it at Upton Fen and at Strumpshaw RSPB Reserve. By 2008, however, the revised Collins New Naturalist volume Dragonflies by Corbet and Brooks was already reporting “some evidence for recent expansion into Suffolk, Lincolnshire, North Kent, West Norfolk and Cambridgeshire”. Interestingly, the species had in fact first been recorded in Britain at Whittlesey Mere, Cambridgeshire, as long ago as 1818, although the mere was drained in 1850. There was even a record from Spurn, East Yorkshire, in 2003. The expansion has continued apace. Today the Norfolk Hawker can be found across much of southern England, extending through the Home Counties into Somerset and Devon. There is then a gap before its more recent colonisation of the north-west, where it is now established around Greater Manchester and Blackpool. Given this steady spread, its arrival in East Lancashire has seemed only a matter of time—and I have certainly been keeping an eye out for it. So what comes next? Which species will reach East Lancashire first: the Southern Migrant Hawker (Aeshna affinis) or the Vagrant Emperor (Anax ephippiger)? One final thought. The threats once listed for the Norfolk Hawker included “the impact of global climate change and fluctuations in water levels”. There is a certain irony in the fact that climate change itself is presumably one of the key factors behind the species’ remarkable expansion and population increase in Britain.
Green-eyed Hawker habitat, Barrow Lower Lodge, Clitheroe (Mike Watson)