Saturday, 29 July 2017

Sanday Sunday

The 2nd day of National Dragonfly Week saw the the OrkOdo team (Our Lass, the Admiral and me) catching the mid-morning boat from Kirkwall on mainland Orkney to the low-lying island of Sanday. We were to meet up with Emma, the Island Ranger, and her husband Russell, at the community hub, Heilsa Fjold. The forecast was for bright and breezy weather, with the threat of showers later. Not ideal, but if you set the bar too high in Orkney, you'd never leave the house!

As well as Emma and Russ, a local mum and her son, Leanne and Luca, came along too, and we set off in two vehicles to explore the myriad water bodies of Sanday. First port of call was a small pool near the western tip of the island. It was on a hillside in rough pasture and, at the time of our visit, was facing the oncoming wind. Undaunted, we stared and stared at the water's edge, the floating water weeds and any emergent vegetation, until one of us 'got our eye in' and the Admiral yelled "Blue-tailed Damsel!" Sure enough, sat on the water's surface, a few feet out from the bank, was a (probably) immature male, his green thorax not yet the same blue colour as his 'tail light'.

Soon, Russ was finding exuviae, the shed larval skins of the emerging adult insects, on vegetation at the water's edge, although trying to transfer these delicate, ephemeral items to a sample pot in a strong wind was interesting!

However, we did manage a few, so everyone was able to see these at close quarters, as well as an adult damselfly that I managed to coax into a larger pot with a magnifying lid.

The next few water bodies, as we headed back east along the island, looked promising but failed to give up their odonatological secrets, if they had any, so after lunch we decided that we definitely needed to find damselflies at our next port of call.

Nothing seen here
Fortuitously, this was at Whitemill, a part of the island I had not previously visited, and although it was only separated from the sea by a bank of tall sand dunes, we struck odo gold straight away. The breeze was blowing across this pool towards us, which meant that the intervening flag (iris) bed was providing some shelter from the wind on its lee side, nearest to us. Also here was a lower stane dyke, whose upper stones were warmed by the afternoon sun. It was damselfly heaven: shelter from the breeze, a warm loafing area, and food on tap, as countless midges were falling into the slack air behind the tall flag irises.

There's at least 7 damsels in this shot

We could even watch the more adventuresome Blue-tailed Damselflies manoeuvring in and out of the flag bed, chasing other insects. Searching for this phenomenon on other islands during the week became known as the Sanday Flag Technique.

By the time we had also visited a site on the north east end of the island, we had seen about 70 Bluetails for the day, as well as being shown some excellent dragon/damsel habitat. My grateful thanks went to Emma and Russ for their tour, and to Leanne and Luca for turning out to help look for matchstick-sized insects on a big (for Orkney) island.

Apart from the stone wall shot, all photos courtesy of Alan Nelson.

No comments: