Tuesday, 16 June 2009

Criticism accepted

Heysham Obs
............re-not enough detail for visiting dragonfly enthusiasts on how to 'connect with' Red-veined Darter.

Here goes on the darters:
The model boat pond is the first on the right after driving into Middleton Industrial Estate/Heysham Business Park. Park in the small car park after going under the height restriction barrier. cSD418590

The western edge of the pond has a small inlet about half way along, just beyond where a line of rushes extends out into the water (rushes, not Reed Mace). Stand on the corner by these rushes and wait and watch the open water and/or check waterside stones for basking individuals. Also check the rippled water in the centre of the pond - these insects can spend quite a lot of time 'in the middle'.

This is where a lot of people go pear-shaped! The best time is not during the late afternoon high temperatures when the species can be very hard, if not impossible, to locate. Time your visit on a sunny day for about 1130-1330hrs. Avoid wind speeds of more than F2 and beware of sunny but chilly north/north-westerly airstreams which may only lead to a temperature high of about 15 C. This is often not enough and 17-18 C minimum seems to be necessary to guarantee this species' activity at this site. Therefore you have about one hour as the conditions in the next few days are not suitable!

Obviously the usual pale-centred pterostigma plus red venations (best seen when insect facing in flight - see photos from two days ago taken by Chris Adams) & all the other stuff as per text (eyes etc). However many people may need to sort out the odd Red-veined from a few additional Common and this is where flight/jizz awareness comes in. These are based on many hours of watching this species at this site:

a) They do not gain height whilst hovering (Common usually do)
b) Whilst patrolling the water invariably keep to the same low height (Common vary)
c) Often change direction far more acutely than Common Darter and this again is done at the same low height (Common vary their height regularly, especially when changing direction)
d) Spend longer over the water than Common

Obviously, jizz is not 100% foolproof, but it may help to get on to likely candidates which can then be carefully checked for "plumage features"

Apologies for the sea buckthorn along the western edge - problems with clearance due to Great-crested Newt legislation

Middleton IE 1120-1145
Red-veined Darter - three on the model boat pond, one very active
Black-tailed Skimmer - 4+ on the model boat pond

Great White Egret still hiding in the main dyke at Leighton Moss. Single Osprey seen at Leighton. ?Returning fsp Spotted Redshank Conder Green. Ad Med Gull Kent Estuary.