Wednesday, 21 August 2013

Here be dragons...

So a few people have asked me now where I am downloading my wildlife photos from... the cheek of it!

Close-up of a Downy Emerald dragonfly (Cordulia aenea), Horleyland Wood Pond

It is mostly down to this brilliantly simple digital camera, which my friend gave me after he upgraded to a fancy SLR one. It is awesome for close up stuff but for distance shots it is not so great, hence why my bird and mammal photos are lacking.

My simple Canon point 'n' shoot camera with good macro setting

This year we have really focused our efforts on recording those beautiful winged hunters: the dragonflies and damselflies. We are lucky to have such a variety of wetland habitats about the airport due to its operations and infrastructure; some are quite odd such as water treatment ponds and consistently marshy grasslands.

A few of Gatwick's wetland habitats:


Dog Kennel Pond (water run-off holding area), populated with sedges, Reed, Typha, and Watercress

Compost Field Scrape (caused by tractors churning up the field) with Typha, rushes, Stonewort, Floating Sweet-grass and Brooklime 

A backwater along the River Mole (artificially sculpted in the millennium)
 with Water-plantain, Arrowhead, Starwort and Bur-reeds

I'm pretty keen to set up more intensive aquatic invertebrate surveying next year of these wetland areas as they seem to contain quite an abundance of wildlife. Dragonflies and damselflies are voracious predators of other insects, so can act as good indicators of life and quality of these habitats.

A male Azure Blue damselfly (Coenagrion puella) munching on a chironomid midge, so intent on its breakfast that it didn't mind being picked up

In order to get a good scope of all the different species it pays to do several surveys spread throughout the season. Dragonfly expert David Chelmick was the man for the job, armed with his many-pocketed hunting jacket, keen eyes and a trusty dictaphone (avoiding the age-old problem of scattered pens and pencils in the field). David's avid descriptions of the secret lives of these creatures are of more violent and intriguing stuff than any TV drama (excepting maybe Game of Thrones, but those dragons were not half so colourful).

No need to journey all the way to Westeros; our section of the River Mole is full of dragons

Dragonflies:

An adult male Brown Hawker dragonfly (Aeshna grandis), Goat Meadow.
 I was shown how to carefully handle them by their wings

A recently emerged Four-spotted Chaser dragonfly (Libellula quadrimaculata), Compost Field. 
Their bodies and wings are delicate and easily damaged at this stage so best to avoid netting them

Four-spotted Chaser dragonfly (Libellula quadrimaculata), Compost Field


Male Broad-bodied Chaser (Libellula depressa), Dog Kennel Pond

Female Broad-bodied Chaser (Libellula depressa), River Mole

Downy Emerald dragonfly (Cordulia aenea), Horleyland Wood Pond

The exuvia (the outer skin) of a Common Darter dragonfly (Sympetrum striolatum), River Mole

Brown Hawker dragonfly exuvia (the purple bit is just a flower from Purple Loosestrife), River Mole

All dragonflies and damselflies begin their lives in the water as larvae; hunting and shedding their outer skins as they grow. Eventually they crawl out of the water and shed their skins one final time. Once a dragonfly has emerged and dried out, it opens out its wings and does not close them again over its back. The damselflies however tend to sit with their wings folded back...

Damselflies:

Male Azure Blue damselfly (Coenagrion puella), River Mole

Male White-legged damselfly (Platycnemis pennipes), River Mole

Female White-legged damselfly (Platycnemis pennipes), River Mole

A mating pair of Azure Blue damselflies (Coenagrion puella). The blue male grasps the female behind the head, she then bends her abdomen up to his genital opening to complete fertilisation. Impressive!

Male Banded Demoiselle (Calopteryx splendens), the dark wings patches are a deep iridescent blue. These guys have a lovely courting display for the green females. 

Finally, a list of all the Odonata species which we have recorded around the airport so far:

1. Azure Blue damselfly (Coenagrion puella)
2. Common Blue damselfly (Enallagma cyathigerum)
3. Large Red damselfly (Pyrrhosoma nymphula)
4. Blue-tailed damselfly (Ischnura elegans)
5. White-legged damselfly (Platycnemis pennipes)
6. Red-eyed damselfly (Erythromma najas)
7. Banded Demoiselle (Calopteryx splendens)
8. Beautiful Demoiselle (Calopteryx virgo)

9. Common Darter dragonfly (Sympetrum striolatum)
10. Broad-bodied Chaser dragonfly (Libellula depressa)
11. Four-spotted Chaser dragonfly (Libellula quadrimaculata)
12. Southern Hawker dragonfly (Aeshna cyanea)
13. Brown Hawker dragonfly  (Aeshna grandis)
14. Emperor dragonfly (Anax imperator)
15. Downy Emerald dragonfly  (Cordulia aenea)
16. Brilliant Emerald dragonfly (Somatochlora metallica)