Wednesday, 22 September 2010

Geese 'n Swans.

Whooper Swans. David Cookson.

The geese and swans are coming, in fact in the case of the geese they're already here with c.3,500 - at an early date for such a high number - on Pilling Marsh last Friday 17 September. In the case of the swans perhaps we will be seeing them in two/three weeks time. Thanks for the photograph David....brilliant as ever.

It was great to find c.3,500 Pink-footed Geese on Pilling Marsh last Friday and I look forward to the added interest in these birds with the possibility of finding some with neck collars and - in the case of swans- leg rings along with the associated often frustrating challenge of reading the marks with birds distant, in water, or in long vegetation. Not many winters ago I had already seen and read fifteen Whooper Swan rings just weeks after their arrival but this was exceptional. There is the added interest in seeing the history of these birds with some amazing movements being recorded through observations of marks.

Whooper Swans (WS) breeding in Iceland have a much shorter migration journey of 800km to wintering sites in Britain than do the Bewick's Swans (BS) which fly some 3,200km from breeding grounds in Arctic Russia, as a result the WS usually arrive here about four weeks ahead of the BS in autumn, and conversely leave a similar period of four weeks later the following spring. All these migratory movements are of course related to the weather, if for example there is low pressure over Britain for most of September with winds in a predominantly southerly direction in the latter half of the month, autumn migration from Iceland by the WS can be delayed by up to a couple of weeks. With regard to the BS, movements from summer to winter grounds is also controlled by the weather, for example, if climatic conditions are mild across Northwest Europe throughout October, with winds mainly in the west, the eastward movement of the BS can be slow not only from the continent to Britain, but from Russia to wintering sites in the Netherlands and Germany.

Greylag Geese.   

Since 1998 a total of 1,281 Greylag Geese on Tiree and Coll have been fitted with neck collars as part of a detailed study of the populations and movements of these birds. Some 13,000 sightings to April this year have shown them to be remarkably sedentary, with regular small movements within and between the two islands but very few beyond them. It was therefore with great surprise that Kane Brides reported a neck collared Greylag Goose at Martin Mere WWT Reserve in Lancashire on 27 March this year. This bird had been marked on Tiree as K82 as a first summer male on 4 July 2009 and this subsequent long southerly winter movement of this individual was most surprising and was last seen at Martin Mere on 29 March just two days after its arrival. It will be interesting to see where this bird is next observed.

Of course my personal best ever sighting of marked birds was that of two Bewick's Swans I found on 5 January 2002 at Preesall, and were subsequently found via a history print out to have been two truly remarkable birds.



Colin Bushell said...

Brilliant new header photo Pete.


Pete Woodruff said...

Thanks for your kind comment re the header, the only birder in the 'area' to have found a Lapland Bunting....Great stuff and welcome back to the UK Colin.