Saturday, 19 October 2013

Sardinian Survivor?

Tuesday I needed a change of scenery after two weeks of Yellow-browed Warblers and little else on my usual patch. I took the opportunity to head up to one of my favourite birding sites - Mire Loch at St.Abbs Head NNR (Borders) - to catch up with the male Sardinian Warbler that reappeared on 25th September after first being present in June.

Sardinian Warbler, Mire Loch 27.09.2013 Bruce Kerr

Active and showing well as it fed in the low canopy just above the main path, I watched it for a while before moving off through the scrub to search for migrants. A couple of Yellow-browed Warblers, a Mealy Redpoll and rear end views of an elusive Red-breasted Flycatcher later it was time to go.

On the drive back south I began to wonder about its prospects if it stayed and what was the latest date for previous Sardinian Warblers, so resolved to dig out some details when the opportunity arose. 

The BirdGuides ORB Archive was a good place to start. Delving into the records revealed that by the end of the 20th century none had made it past 11th November; an adult male in Shetland in 1992 holding the prize for staying power.

Perhaps the best indication of whether a Sardinian Warbler could make it through a British winter came in 2002/03 when a male first found in Norfolk at Old Hunstanton between 27th September and 15th October 2002 was thought to be the same individual that reappeared over 16th-24th Marsh 2003.

Again in 2003, a male and female in Skegness, Lincolnshire made it through to 4th January and 11th January respectively. Was it a coincidence that all three of the longest-staying individuals recorded in Britain happened in the same year? What seems apparent is that winter 2002/03 was fairly tame, perhaps on the dry side with little by way of prolonged snowfall or rain after the Autumn, at least on the east coast (see here for one summary). The second half of winter, the first three months of 2003 provided the sunniest start to a year since 1893 (source).

Hardly a revelation that mild winters help might increase the chances of one of these Mediterranean warblers getting through a whole winter. So the prospects for the St. Abbs Sardinian, in its location sheltered from the worst of the gales to the east, are probably not brilliant, but given a mild winter it might at least make it into 2014.

1 comment:

Graham Catley said...

Sardinians in Southern France seem to survive well enough through some pretty severe January weather; we have been in Provence when day time temps seldom get above freezing and night temps down to -10C so Sards are maybe a bit more hardy then some of the other sylvias more akin to Dartfords and even Cetti's -- the 2003 Skeggy birds were in a mix of scrub with a lot of sea buckthorn that offered berries as an alternative food supply through to about the time when they disappeared when the berries typically rot and drop ff if they have not been eaten