Tuesday 12 September 2017

Grimsbury Grey Phalarope 12th September 2017

Grimsbury Reservoir lies on the outskirts of Banbury, just in Oxfordshire. It can hardly be called attractive as it is a small rectangular body of water surrounded by mainly concrete  with the town of Banbury, industrial estates and the ever busy M40 Motorway close by its perimeters. There is a constant background roar of traffic noise from the roads and occasionally interesting and not unpleasant smells come from the former Kraft Foods factory nearby, if the wind is coming from that direction.

Yesterday, however, a little bit of avian glamour and foreign mystique came to grace the reservoir's unforgiving concrete shores in the form of a juvenile Grey Phalarope. Strong, gale force south westerlies brought quite a number of storm driven Grey Phalaropes to various inland waterbodies yesterday, places they would not normally frequent. Usually when this occurs in Oxfordshire it is Farmoor Reservoir, a much larger body of water, which receives them but this time it was Grimsbury's turn and a just reward for the almost constant watch kept on it by Gareth and John.

These storm driven phalaropes, so far inland, must be glad of a suitable place to put down and rest. Although they are miles off course from their normal oceanic habitat, the next best thing are large and open bodies of water such as Grimsbury and Farmoor Reservoirs. Normally they should be heading far out to sea where they will lead a pelagic existence  in tropical seas off West and South Africa, not coming to land until they return to their breeding grounds in the Arctic regions of Eurasia and North America. 

Storm driven Grey Phalaropes in Oxfordshire and elsewhere are usually ridiculously tame and allow one to approach them closely. Although these storm driven birds are generally encountered singly Grey Phalaropes are gregarious for most of the year and often migrate in flocks.

Knowing that I had a golden opportunity to see another confiding Grey Phalarope in Oxfordshire and only thirty minutes drive from my home, it was too good an opportunity to pass up, so I made the short journey to Grimsbury Reservoir this morning and parking the car just off the busy ring road, walked along the edge of the reservoir to find it. There was only one other birder present this morning, while yesterday its arrival managed to attract as many as eighteen people. This was quite a good number for Grimsbury and I am sure others will visit, if as they often do, it remains for some days or even weeks.

Grimsbury Reservoir - Kraft Foods in the background!
I found the phalarope feeding along the shoreline at the far end of the reservoir and doing what all Grey Phalaropes do, swimming close to the shore and picking items from the surface of the water. However, unlike most other Grey Phalaropes I have encountered locally it also showed a predilection for walking on the concrete edge where it met the water. This was unusual as mainly they prefer to swim when looking for food.

Note the lobed toes

It was an opportune chance to study its highly adapted feet which have grey toes each fringed with a number of lobes, somewhat similar to those of a Coot and doubtless an adaptation to allow it to swim freely when out at sea. It did feel extraordinary to see the lobed grey feet so well as it alternated between feeding on land and feeding on the water and at one point it stopped to rest, squatting with its head sunk into its shoulders and facing out over the water. Could it still be tired or unwell from having to deal with the strong winds that had blown it so far off course?

The adapted feet and toes can be seen through the clear water

The plumage of this bird was very well advanced into its first winter plumage of all grey upperparts and white underparts with a white head sporting a square black patch behind the eye. Often they do not reach this advanced stage until late October. Evidence of its age were the presence on its wings of at least one un-moulted brown tertial, possibly more and some brown wing coverts, which was the sum of all that remained of its juvenile plumage. 

I watched it for almost an hour as it fed along the shoreline and then left it in the sun, still actively feeding on the water.

Grey Phalaropes are, along with their close cousin the Red necked Phalarope, the most oceanic of all three phalarope species, migrating via sea routes to their winter quarters. They only occur inland when blown there by very strong winds. There is some uncertainty about where exactly they winter at sea but it is becoming evident that major concentrations occur where ocean currents converge, causing upwellings of plankton off western Africa and western South America. They also often feed around groups of whales. There is evidence that North American populations also head for the seas off Western Africa to spend the winter. When North Atlantic populations are migrating from their breeding areas they usually by-pass the North Sea heading out into the Atlantic but gales coming in from the Atlantic can drive numbers onto the coasts of Britain and Ireland and a number end up far inland. 

This was undoubtedly the fate of this Grey Phalarope. Let us hope it survives and remains at Grimsbury Reservoir for a few more days. Looking at the weather forecast for tonight and tomorrow it would be wise to do so!

The exceptionally high winds of the night of 12/13th September resulted in another two Grey Phalaropes being found in Oxfordshire the following day, the 13th September. One at Sonning Eye and the other, unsurprisingly, at Farmoor Reservoir. In fact storm driven Grey Phalaropes were being reported from all over England with an amazing eight at Abbotsbury in Dorset.

A fourth Grey Phalarope was found at Bicester Wetlands Reserve on 18th September.

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