Sunday, 7 May 2017

Another busy day, with an astoundingly unlikely highlight. To get one PALLAS'S WARBLER in a spring is pretty remarkable. Find a second, and it starts to beggar belief. 

Pallas's Wabler breeds in mountain forests from southern Siberia east to northern Mongolia and northeastern China. It is named for German zoologist Peter Simon Pallas, who first formally described it. It is strongly migratory, wintering mainly in southern China and adjacent areas of southeast Asia, although in recent decades increasing numbers have been found in Europe in autumn.

The record on 18 April this year was the first spring record for Bardsey and for Wales. So when another arrived here today, we began to wonder what was happening!

Phylloscopus proregulus
(Pallas, 1811)
Phylloscopus proregulus map2.png
  Breeding summer visitor
  Winter visitor
For today's individual to have, against absolutely minute odds, already been ringed prior to its arrival on Bardsey makes this a good candidate for the most exciting and unusual recovery Bardsey has ever had! When it was first observed that this bird had a ring, the common sense assumption was that it was the same one ringed here on 18 April, and had somehow remained hidden for a very long time (I'd postulated, half jokingly, that it realised Scotland wasn't much of a breeding location and was retracing its steps South!). But stellar fieldwork and photography allowed for five out of six of the digits on the ring to be clearly read in the field (and the other one was suspected), which confirmed it definitely wasn't our bird! A little bit of detective work from Mark Grantham at the BTO and it was confirmed that JKV435 was one ringed at Spurn Bird Observatory on 11 October 2016. We had clear images of all the digits except the K, but that was enough for Mark to be able to confirm the bird was this one below from Spurn!

Pallas's Warbler taken from SBO website - photo Dan Branch

A fantastic recovery, but the one question we all want to know is where it spent the intervening seven months! Presumably wintering somewhere in Southern Europe or North-west Africa. This is undoubtedly our most exciting bird of the year so far, and a great illustration of the fact most spring Sibes surely are returning North having successfully overwintered. Will Pallas's Warbler one day be nothing more than a scarce winter visitor and spring migrant through Europe, with a secondary migration route to its breeding grounds established? This recovery posed many, many more questions than it can possibly answer, but it will be fascinating to monitor the occurrences of this and other eastern rarities over the coming years.

It was a fine day to be out, even without a cracking rarity. A good scattering of migrants featured highlights of a Wood Warbler, two Pied Flycatchers, singles of Whinchat and Ring Ouzel and an excellent five Lesser Whitethroats. Also noted were 83 Willow Warblers, 36 Wheatears, 20 Whitethroats, 18 Lesser Redpolls, 14 Chiffchaffs, 11 Sedge Warblers, eight Spotted Flycatchers, seven Blackcaps, three Garden Warblers, three Redstarts, two Yellow Wagtails, two White Wagtails, two Rooks, two Collared Doves and singles of Siskin and Grasshopper Warbler.
Pied Flycatcher
Lesser Whitethroat

Overhead, 393 Swallows moved through, as did 35 each of Sand and House Martins, five Swifts, three Tree Pipits and two unseasonal Skylarks. Another fine wader day featured 21 Dunlins, 19 Whimbrels, 15 Ringed Plovers, 13 Turnstones, 12 Sanderlings, six Purple Sandpipers, five Curlews and lingering singles of Grey Plover and Bar-tailed Godwit.

Out to sea, an early morning burst of 218 Guillemots were on the move in the first two hours of daylight. There were also 96 Kittiwakes, 56 Manx Shearwaters, 39 Gannets, two Puffins and singles of Black-headed Gull and Great Northern Diver.

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