Monday, 3 October 2016

Spryte Fever

Yellow-browed Warblers, the six striped Siberian spryte, have reached the critical mass to have become not just a frequent migrant through September and October along the coat but now an annual and expected occurrence within the Ely10.  This is due to the success of mutations along strands of DNA sequences that code for a pioneering reverse migration.  Where this is of benefit to an individual it may survive to pass this code on to some of the next generation of offspring, particularly likely if the mate has also survived a reverse migration.  Somewhere out in Siberia there is a zone where a chunk of the Yellow-browed Warblers are now migrating to Europe for the winter, surviving and returning to breed with success and conceivably a breeding advantage leading to increasing numbers year on year.  What doe this mean for the future of these Sprytes in the UK?  Well in the short term we may expect finding even more Yellow-browed Warblers on the coast and inland during the autumn and in significant numbers in the right conditions for drift migration of birds already arriving in Scandinavia.  Other likely occurences will be a distinct increase in wintering birds, due to the difficulty of finding these unobtrusive birds inland, records may not fully reflect actual numbers until they become more common, in the vein of wintering Chiff-chaff or Blackcap.  Intriguingly the possibility of genetic mutation within a growing population of reverse migrant Sprytes increases and could lead to a bird or two remaining to hold territory where the midge-ridden birch woodlands of Scotland could provide a suitable niche for them to occupy.  Of course the current trend could falter and Sprytes may return to their previous rarity status.  Hypothesising aside, the increasing frequency of Spryte's as a feature on a birding daylist is a joy. 

In the past fortnight there have been four Sprytes found in the Ely10, amazing stuff.  This bird found it's way in to Tony Martin's nets at Dunkirk.  A belter, I've snipped the pic from the Cambridge Bird Club photos page and hope that I'm causing no offence by doing this.

Others have been seen and heard at Soham (a hotspot with 3 records) and along the Washes at Fortrey's Hall found by Spryte diviner, David Hopkins, who finds them near enough annually now and must have found more than any other birder in the county.

Yesterday a twitchable Spryte finally settled at, Ben's nab tip site, Thistle Corner.  Mark Welch and his son Luke have been working this site with frequency and diligence  for awhile now but mostly focused upon Diptera and with plenty of success.  A calling Yellow-brow is an arresting sound to a birder, and Mark is a particularly avid sonophile, so when he heard that vibrant and zesty tezveeet  I'm sure his heart did a little flutter of excitement.  I'm looking forward to exchanging a celebratory Southwold Bitter for the story in detail next week.

So over several visits I saw this Spryte plenty.  It was a skulker and canopy tied.  Most views were obtained by following the movement of the bird into gaps in the Maple and Ash tangle it favoured, cumulative views of stripes tantalised. 

Like this.......


and this......

Eventually the bird spent a bit of time in a sun drenched Horse Chestnut.  Ben's camera fired off like a machine gun and he should have a few better shots but these give a flavour of this beguiling and tricky bundle.

Mostly it though it was a game of Where's Wally????

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