BTO migration blog
Monday 26 September 2011
Tuesday 13 September 2011
Strong westerlies, particularly those associated with fast tracking storms that cross the Atlantic in a day or so often bring North American birds with them, and this weekend’s storm did just that; over thirty Buff-breasted Sandpipers arrived in the UK during the weekend. This high Arctic breeding wader leaves its breeding grounds in Alaska and western Canada during August and September, heading for the Paraguayan and Argentinian pampas. The eastern breeding birds complete this huge migration in one long flight over the sea from New England to Paraguay and Argentina, so are often prone to getting caught up in these fast tracking storms. The winds also brought the first American passerine to our shores, a Red-eyed Vireo, to the Isles of Scilly. This bird would have been making its way to northern South America or Cuba.
Monday 12 September 2011
Manx Shearwater by Joe Pender
All four species of Skua were also involved in this movement, with Arctic being the most numerous, again the BirdTrack reporting rate shows this increase.
As was to be expected, the fast tracking Atlantic gales brought North American Waders with them and over a dozen Buff-Breasted Sandpipers arrived on our shores, with the Isles of Scilly hosting five of them, again the west received the lion’s share but birds have been found at Rye Harbour in East Sussex and Titchwell in Norfolk.
Buff-breasted Sandpiper by Joe Pender
Despite the windy conditions Swallows and Meadow Pipits have been a feature of visible migration watches. Over 12,500 Swallows were counted heading south at Spurn Point last Saturday, with almost 8,000 Meadow Pipits heading in the same direction on Thursday.
Swallows gathering by Paul Stancliffe/BTO
The first large finch movement was also observed here on Thursday with over 600 Siskins also heading south.
With the wind set to increase again from the west yesterday, observers on the west coast should have been in for another weekend seabird fest, whilst in the east, finches and pipits should make the most of any lull in the windy conditions.
Question of the week - How do birds cope with the risks of migration?The very act of long-distance migration has to be one of the most arduous and dangerous activities that a bird undertakes, so what can they, and indeed do they do to minimise the risks associated with long-distance migration?
For those migrants that undertake long sea or desert crossings, it is essential to store enough fat deposits to fuel these flights and many of our smaller birds spend up to three weeks feeding up and accumulating fat reserves before their departure, some will have more than doubled their normal weight.
Setting off in optimum conditions also helps to minimise the risk of being downed or blown off-course and also maximises the stored fat reserves. If birds encounter worsening conditions, many will make landfall and rest-up and feed-up until conditions improve.
Some birds migrate primarily at night, reducing the risk of predation by diurnal raptors. Flying in the cooler night air also reduces drag and minimises the use of the stored fat reserves.