Saturday, 12 February 2011

Wknd 12-13 February

Swans circuit in Holyrood on Saturday morning produced a few with the new bright green darvics; Greylag DZC was still alive, right (domestic Greylags history in link right). 12 occupied herons nests at Duddingston; oh yes, the first year Iceland Gull too was unmissable on Dunsapie - was successful in grabbing 2 large bits of bread and actually looked quite bloated with food; not content, I then saw it successfully parasitise a BHG, which dropped its own bread.

Then did the NT47J TTV - this is the tetrad offshore NW from Ferny Ness; arrived early afternoon in hope of some mud at low tide but tide never dropped far enough to reveal any shore, thus had to count sea duck instead - total 689 in the tetrad: 328 Velvets, 151 Eider, 92 LTD, an unprecedented (for me) 90 Goldeneye, 19 RBM, 8 Common Scoter and rarest of all a female Tufted Duck; also 39 Slav Grebes and 3 Razorbill; all minima with birds busy diving to feed. Some reasonable counts for the TTV but poor in comparison with yesterday's 78 Slavs, also the BNG and GND seemed to be absent though had been seen earlier and disappointing to get no other divers (though these all logged for tetrad previously).

Then did WeBS, a day earlier than usual; 160+ Whoopers remained at Muirton; an ad f Scaup and pr RBM were still on Chapel; Mute flock in upper Peffer Valley, south of Dirleton, has reached 39; Grey Wag at East Fortune was the first I remember hearing for a long time, and vocal Wrens in several places was encouraging too.

The taiga Bean Goose was still at Waughton, with a dead swan below wires there (foot measurement suggest Whooper), a very sad sight considering the effort that was expended to get the bird deflectors up on the wires in April 2008 (after at least 15 swans had perished that winter, commuting between the "bean" field and the resr to roost) - photos below. Plastic disks were fitted to the 11kV line and big orange fishing float type (sourced in Leith) on the 33kV line (LBN post). The density of deflectors above where the current bird had fallen was 7 on a span - perhaps more are needed to be effective, but probably it is impossible to make it fully swan-proof given they will often fly to roost after dark. Use of fluorescent markers has been discussed but I have seen no proof advanced that these will work and I suspect they may just confuse the birds which will still not be able to see the wires themselves. For extreme cases it might therefore be better to disperse the swan flock via other means.

[Postscript - have since discovered that more frequent terminology, at least in the US, is bird "diverter", and found a couple of articles demonstrating the successful deployment of deflectors in the UK (at Abberton resr and Rye harbour). Commercial products in the UK here and use of reflective material on deflectors intended for cranes mentioned here].

Sunday had a look at the Seton roost - there was one unringed adult Med Gull on the shore off caravan park entrance, c/o Mike; 3200 small gulls roosted, the last flying onto the sea at 17:40hrs; c. 35 Herring Gulls remained to roost, but still no LBB arrival.

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