Saturday, 12 January 2013

Wknd 12-13 January

Went out for WWT swan census and WeBS on Saturday. Plenty wildfowl about, over 1500 geese at East Fortune (some of which above), c. 910 Greylags might be another new high for this site (previous peak 817 on 10/12/10). Continuing wildfowl were 1st-win drake Scaup at East Fenton, getting into adult plumage, and ad drake Gadwall at East Fortune. A male Peregrine again flew over Brownrigg.

Grappled with the swans at Prora, some recent exodus with total fallen from c. 235 to c. 206; I estimated 46 juvs (22.3%) but it was hard work with whole flock only visible from Chapel and many juvs now very white so a close view to see beak colour required, many beaks also caked in mud! Only three darvics seen, juv red-AVJ and ads red-BLX and yellow-46I (shown above together). Latter is particular interesting as this bird had been wintering on the River Blackwater in SW Ireland 08/09, 09/10 and 10/11, first seen with us last winter 11/12 - but seems to have returned! Ringed at Jokuldalsheidi in Iceland as a cygnet in August 2003. Nearby 6 Mutes in cereal included green-NLT, below. Checked Ware Road, Lochhouses, New Mains etc for more swans but only found a Mute flock at Preston, by East Linton, including green-NLD. Perhaps there are no Whoopers wintering at Tyninghame?

At dusk tried again at Inch Wood, Binning, for Tawny (still needed for NT58V for atlas); this was 7th attempt, started after sunset walking into wood, encouraged by vigorous Blackbird alarming at two locations; staked out one but no sign and eventually Blackbirds went quiet - but then at 16:47hrs (43 mins after sunset) hooting started nearby, success at last. Departed south and pulled in at Birkhill, with a minute 3 Woodcock flew over, a single then two in tandem - increase count from one.

Sunday - took a walk along the Back Burn past Ustonrigg to Woodside ponds and back via Hopefield and Letham Mains. Highlight was a female Merlin dropping from edge of ponds and streaking off across the field N towards a flock of Linnets, came up through the flock but missed; these were c. 120 Linnets, another 240 were perched a little further along perhaps already alerted to the Merlin. 3 Woodcocks flushed, probably many more in the area if I had covered more ground around ponds. 6+ Jays and 11 Bullfinch, both good counts. Finally there was a gathering of 45+ Waxwings by the A199/B6363 roundabout south of the A1 junction.

BirdTracked all the sightings by tetrad, discovered only the Merlin was new for atlas, increased counts of perhaps 5 others. Additions are expected to be slow at this stage in the project - by the modelled species accumulation curves fit for our 10km (NT47) in the atlas trial (see LBR06 write-up, p. 96) we expect of the order 2% addition to species lists in the 4th hour of fieldwork, which with species lists already of order 50 equates to one addition. Each subsequent hour provides rapidly diminishing returns (in theory), approximately 1/3 of the previous hour. Spent about 2 hours today and each tetrad may already have had 2x2hrs of visits, so one addition is in the right ball park, already well covered. Suspect the theory may be less applicable with various permutations: different observer (goes to different places/sees different things), different date in season - some movements missed, and especially year-on-year variation - mild winter may bring new species, e.g. lots of recent Mute Swan additions, in fields which they could not have occupied with snow cover. Overall now 128 tetrad ticks in East Lothian this final winter, with 7 weeks to go to final termination, these may well represent 100s of hours in the field. We must be getting close to reasonable maps!

On Monday, finally a Tawny Owl at New Winton, kewick calls in response to hooting imitation from New Winton Wood NE of main square, atlas tick for NT47F (after 6 negative visits!).

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