Wednesday, 15 May 2019

World Travellers at Farmoor 8th May 2019


Farmoor Reservoir can be a good place to see migrating waders in late April and throughout the month of May and none more so than the diminutive Sanderlings and Dunlins which  appear without fail at Farmoor each year undergoing their phenomenal migration from, in the case of the Sanderling, possibly as far away as South Africa and bound for Greenland and northern and central Siberia to breed.
In the case of the Dunlin, there is the possibility of no less than three different races, arctica, schinzii  and alpina stopping off at Farmoor. Arctica winters in northwest Africa and heads for northeast Greenland to breed. Schinzii also winters in northwest Africa but heads for southern Greenland, Iceland, Great Britain and the Baltic to breed. Alpina can be found in winter in Britain, France and the western Mediterranean and breeds in Norway and northern Russia.

The differences in the Dunlin races  relies on bill length, size and subtle plumage differences such as upperpart colouring and the size of the black belly patch in breeding plumage but differentiating these subtleties between birds at  Farmoor is extremely difficult and there is inevitably a degree of speculation about the racial identification of migrant Dunlins at Farmoor in breeding plumage. Nevertheless it can be fun trying!
Farmoor, with its shoreline of algae encrusted concrete, provides the nearest equivalent to a seashore and a welcome if but brief resting place as the waders cut across central England heading north. These tiny birds do not tarry long as they still have a long way to go and the urgency of Spring makes them eager to press on but rest they must and feed if they are to stand a chance of reaching their final destination.
Dunlins usually outnumber Sanderlings but often a delightful mixed flock of the two species will arrive and spend the day as one, in each others company, before departing. Such a day occurred  on 8th May when a morning and early afternoon of heavy rain showers persuaded a flock of eight Dunlin and two Sanderling to spend the day on the reservoir, running up and down the shoreline feeding on the minute prey they found at the water's edge.

Very often they are quite confiding and it is impossible not to be charmed by their trust and the way they look up at you quizzically and maybe a little apprehensively as you stand nearby on the causeway looking down on them. Sit quietly though, on the low retaining wall of the causeway, and they may lose any remaining fear and approach until right opposite but any sudden movement will put them to flight or cause them to run on twinkling legs in the other direction.

Many of the Sanderling seen at Farmoor are still in the predominantly white plumage of winter (see the bird pictured below) but will slowly moult into a much richer chestnut coloured plumage although the variation in intensity of their breeding plumage is very marked in this species and it is thought that many do not breed until their third year of life and do not attain the really rich rufous colour until then.


A Sanderling in full breeding plumage

Two Sanderling

Eight Dunlin and two Sanderling

Six Dunlin and two Sanderling.Note the small Dunlin fourth from the right

Two Dunlin and one Sanderling

Eight Dunlin and two Sanderling

One Dunlin and two Sanderling

Three Dunlin and two Sanderling
A few days later another flock arrived but this time consisted only of Dunlin. Half a dozen, that kept close but showed little concern about anyone coming near to them. The Dunlin at this time of year are almost invariably in summer plumage and looking ultra smart. Such a transformation from their unremarkable grey winter plumage.

Dunlin. The small bird on the left may well be schinzii or arctica and the two
behind it could well be alpina

Dunlin - possible alpina
I watched this charming little group making its way up and down the concrete but they seemed less interested in feeding but more inclined to grab whatever opportunity they could to sleep even if it was just for seconds. Their way of sleeping is to shut down one half of their brain whilst the other stays alert so they never close both eyes at the same time. Just as well, for danger is all around, especially here since a Sparrowhawk has taken to patrolling the causeway. 
They stand in repose, on one leg and with their long bill tucked snug into their back feathers  twisting their bodies to ensure the open eye is covering all eventualities. For a brief moment in their frenetic lives Farmoor provides an opportunity for them to rest before embarking on a further marathon of flight to their distant breeding grounds.
World travellers par excellence

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