BTO migration blog

Spring and autumn are exciting times for anyone who watches birds. Here on this blog we will make predictions about when to expect migrant arrivals and departures, so that you know when and where to see these well-travelled birds.

Thursday, 6 February 2014

Spring migration getting underway – or not

There are signs that birds are on the move. During the last week, Bramblings have moved into my garden, and I know from previous years that I may well see them on a daily basis from now until early April. I also know that I get a large turnover of birds during that time – some days there are more females than males, and on other days young birds in their 1st winter dominate. Over the course of the next couple of months over a hundred different individuals could move through the garden, almost certainly on their way to the east coast and, at some stage crossing the North Sea. So, for me, this is one of the first signs I get that spring migration is underway.

Brambling by Jill Pakenham 

In a couple of weeks time, Siskins will be doing the same; moving through the garden. I only ever see a maximum of a dozen or so birds but a couple of years ago, over a three week period in March, almost two-hundred Siskins were trapped and ringed in my garden, proving that there was a large turnover of birds.

Siskin by

But what about the Sora on St Mary’s, Isles of Scilly? It was seen for the first time this year on Saturday 1 February. I say this year because it may well be the bird that was at the same site in mid-October last year. Or, could this be a bird on the move? There is a chance that it could be a new arrival – it was seen just ahead of a deep low pressure system that tracked across the Atlantic at great speed and, although it seems a little early for a Sora to be on the move, the first ones start to appear in southern USA in early March, it wouldn’t be outrageous to think that it could be an early migrant; would it?

I have seen Wheatear, Swallow and House Martin in mid-February on the Isles of Scilly, and those birds must have been on the move in early February and prone to getting caught-up in bad weather. The fact that at the time there was a warm southerly airflow that also brought my earliest ever Hoopoe to the islands obviously helped them on their way, but what if it had been a fast tracking low out of the Mediterranean that crossed the Atlantic to North America in a couple of days, unlikely I know, but in those conditions those birds could have arrived in a very different place indeed.

So, has spring migration already begun? Almost certainly. Is the Scilly Sora a freshly arrived trans-Atlantic vagrant? Who knows? It’s not impossible.

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