Sunday, 13 May 2012

More nocturnals

On Monday took a detour en route home to look for atlas nocturnals, specifically Woodcock, in Midlothian (where current map suggests major decline, but likely just under-recorded). First stopped at the bridge by Lions Lodge near Oxenfoord Castle at about 21:00hrs, immediate clues there were owls around with Blackbirds persistently alarming; after listening for half an hour two Tawnys had confirmed their presence in wailing and kewick calls, perhaps two more based on centres of alarm calls but no young heard, neither any Woodcock.

Went on to woods along B6367 east of Preston Hall which I thought looked good for Woodcock when driving past a couple of weeks ago - within a minute a sneeze call heard, then a few minutes later a roding bird went over, fortunately traversing from NT46D into NT46C and NT36X, all new atlas tetrads.

Tawny also heard there and was just about to go when I spotted a freshly dead owl on verge just in front of car, sadly an adult Tawny (but see below). Considering I'd pulled up at random and may not have seen the bird otherwise goodness knows how many more there are, certainly this species still seems to be thriving locally despite the two bitter winters. Our local atlas map still needs a lot of work, the suspicion is that most of the "losses" are simply lack of monitoring.

Finally pulled up just south of Gladsmuir 22:00hrs, wailing Tawny calls could be heard emanating from Butterdean Wood, several within a minute. Will need to return to confirm breeding here!

Looking more closely at this Tawny specimen age confirmed as 2nd-summer, based on replaced outer primaries p5-p9 (right wing shown, same apparent on left underwing); thus the inner primaries are all retained juvenile feathers, though on this bird they have a more solid looking sub-terminal band than on many.

The most useful info on ageing these birds is the chart c/o Henk Van Konig displayed in this blog post. Whilst BWP indicates that: "primaries start with p1, p2, p3, or p4, halting with p8, p9, or p10" clearly they have not started with p4 on this bird, Henk's chart shows that p4 is replaced only on c. 67% versus 95% moulting p5. This bird is also very similar to the 2nd-summer female in this post c/o South Notts Ringing Group (photo). That one had moulted some secondaries (s8-9), the current bird had s6 missing so was already in moult (in adults, flight-feather moult starts early May to late June, suspended early September to late November, per BWP), and seemed to have replaced s8-10 last year (secondaries numbered from primary junction inwards).

Another example showing a 2nd-winter (slightly younger) also has p1 replaced, which is a bit unusual per Henk's chart. Final lesson here is these moults can vary considerably, thus perhaps some merit in documenting.

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