Friday 5 April 2013

Wader ringing weekend Pt2: Cannon netting.

Our morning started at 03:00 hours when we awoke to get prepared for a 04:00 departure with Nigel Clark the softly spoken figurehead of the group, and some of the team. We arrived at the trapping area in the dark and started to walk along the pathway behind the sea wall hidden from the beach, there were six of us in total. Two people were left at the netting site and four off us moved on further up the beach, there was Nigel, Elis, me and Danni,  who was given a walkie-talkie and instructed to continue up the beach for 150 yards to be 'long-stop´ preventing dog walkers, joggers and even birders from walking along the beach and scaring off all the birds.

A swirling flock of Red Knot on the beach.
The hide in which we remaining three were to wait and observe was a rather small hessian clad structure, no more than four feet in height, and all thoughts of cushy numbers and luxury were soon dispelled. Nigel informed us that we did not have to crawl across the beach (I was stunned that he had even considered it possible that I could) but that we should creep forward crouched down to the back of the hide and then crawl under the back to get in. It took some effort for me to achieve this manoeuvre, but achieve it I did. 

Red Knot on the beach

Nigel talked us through what was going to happen. He would wait for the birds to be pushed far enough up the beach by the tide and then give the order to fire, counting down from three. Elis and I fiddled with our cameras to prepare for the event which we knew may not even happen if the birds didn’t go to the right area or if a single bird were to be in what was called the safety area, which perversely was anything but safe for it. If a bird were to find itself in this area when the canons were fired, it would be blown to smitherines and shredded by the net. If just one bird is in this area, even if the opportunity to catch a thousand birds were missed, the canons would not be fired, as with all ringers, the birds’ welfare is paramount and takes precedence over any other consideration. In order to try and persuade the bird in the safety zone to move, the observer had a 'jiggler' available. This hi-tech piece of equipment was a piece of string that led from the hide to the net that could be pulled. The hope bring that the movement would startle the bird in the zone sufficiently for it to move, but not so much that it springs into the air setting the whole flock off.

A flock takes wing
There were three nets set. Nigel would occasionally inform the firing team of the situation.
          “Arm all three nets, there are some 500 Knot approaching the firing zone.”
          A pause and then,
          “Disarm net one, there is a Grey Plover in safety!”
          So it went on for an hour or so, nets being armed and disarmed, bird approaching and then disappearing from the capture zone, then out of the blue with no warning Nigel said,
          “Three, two, one, fire!” Elis captured a series of rare shots of the cannon net flying through the air. 

As the smoke from the canons faded away a crowd of people rushed down the beach to the nets like an army going ‘over the top’ into battle.

The birds were then put into plastic 'keeping boxes' to be taken to the processing area off the beach behind the sea wall.

There they were transferred into 'keeping cages' which were made of material to stop the birds from harming themselves if they struggled to get out. 

The birds caught were four Common Gulls, fifty-four Eurasian Oystercatchers and three Bar-tailed Godwits.

Two stations were set up, the ringing station and the processing station. The ringing station was led by Aron, a veteran ringer who oversaw, advised and checked on the ringing of every bird, training being given where necessary, great care was taken at all times to ensure no harm came to the birds over and above the minimum that was inevitable by being caught and handled that is.

The ringing station.
Oystercatcher being ringed.
Job done.
Elis and I were offered the chance to ring a bird, but although we did hold a bird in order to get a photo to record our presence and involvement, we decided that as we didn’t know what we were doing it was a stress too far for the birds. Nigel did point out that if the handler was relaxed, then the bird seemed to sense this and relax too, and for my part I actually experienced this. When I was first passed an oystercatcher, I was tense, I didn’t want to crush the bird by being clumsy, nor did I want to let it struggle free. As soon as the bird was firmly in my hand and I realised that it wasn't as difficult as it seemed, I relaxed and the bird stopped struggling, apparently resigned to its fate whatever that may be.

It was very interesting to see the birds close up we were able to compare adults with younger birds and listened to Nigel explaining the ages and moult sequences and we were pleased to note that all birds seemed to be in top notch condition despite the recent cold weather, all moults seemed to have gone through with no apparent problems and the birds looked healthy and smart.

Age comparison of oystercatchers: Adult bird behind in breeding plumage
with a sub-adult still with a winter white collar. Note the  orbital ring and bill
colour plus the colouration of the mantle.
Once the birds had been aged and ringed they were then passed to the processing team who started by confirming the age and taking a wing measurement, next came the combined head and bill measurement and then the bill depth, this was followed with the bird being weighed and then placed back onto a keeping box. Once five birds were completely dealt with and in the box, the box was then transported back to the beach and the birds released.
The processing station.
The bird is aged for a second time to ensure accuracy...
... combined bill and head measurements were taken...
... the bird was weighed...
... and then released back on the beach.
The godwits were given slightly different treatment as they were to receive colour rings and individual identification flags in addition to their metal rings.

Male Bar-tailed Godwit being prepared for ringing, note the snow!

Ringing the godwit

A full compliment of leg accessories!
After the ringing the godwits were reassessed for age, measured and weighed in the same way as the oystercatchers before release.

Inspecting the bird for moult and ageing.

Bill measurements are taken.

Preparing to weigh a female godwit.
The moment of release.
On release some were more reluctant than others to depart...

... taking their time to look around first...
... then they are off...

... and away!

The four Common Gulls looked like a trial to ring, fingers were being bitten and the backs of hands stabbed by these feisty little devils, I was not offered the chance to hold one, nor would I have accepted had I been, that did not look like fun at all.

Common Gull taking a chunk out of one of the ringers, rather her than me!
The oystercatchers and the elegant godwits on the other hand were much more docile and would lie quietly in the ringers hands. Nigel demonstrated an amazing feature of these and indeed probably of many birds and that was their ability to hold their head completely still while their bodies twisted and turned this way and that. This being an adaptation to keep their heads still when flying. He held the bird horizontally and then gently rotated the body through 45° and back, the head did not move a millimetre, he then moved the body up and down vertically just a little to simulate flight, again the head did not move, and nor did it when it was even moved from side to side, quite remarkable to think of the myriad muscle actions that are taking place to achieve this making birds even more remarkable and interesting by the day.

Once all the birds had been ringed, processed and released, the gear was packed up and we returned to base for a much anticipated breakfast.

Packing up the nets after drying.

No comments:

Post a Comment