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.

Wednesday, 27 April 2011

Where are all the migrants?

Migration is usually monitored at coastal watchpoints and bird observatories, where careful daily counts of visible migration, birds flying overhead, and grounded migrants are taken. These counts give the first indication of how our summer visitors have fared over the winter months.
The situation this spring has been very different with many observatory websites reporting very quiet days, in fact looking at the various websites gives the impression that it has been a very poor spring for migrant birds, and by association a bad winter. This couldn't be further from the truth. In the very settled conditions birds have had a relatively easy migration and have flown high over the coast, too high to be seen by observers on the ground, and nocturnal migrants just haven't been grounded.

A walk around my local patch, Lakenheath Fen, on Monday morning confirmed the presence on territory of many summer migrants. Reed and Sedge Warblers were in full song everywhere, as were Whitethroats and seven Grasshopper Warblers. Two Nightingales were singing around the car park, a pair of Common Terns looked settled in on the washland and there was a good number of Swallows, Sand Martins and House Martins feeding over the water, and four Cuckoos were singing for over three hours non-stop. In fact the Fen was alive with summer visitors - a very different picture from the one that coastal observers are getting.

Nightingale by Edmund Fellowes

However, it's not all over yet, we are now coming to the peak migration time and as the winds turn north and north-easterly over the next few days birds could well be forced to fly lower over the coast, and nocturnal migrants could well be grounded. We could see some large counts of hirundines during the day and grounded warblers and chats at first light, particularly on the south and east coasts, and, in the next day or two Swifts should arrive in force, the only thing that might stop them is if the northerly winds become too strong. This is an event that I always look forward to, as it seems that all of the UK's Swifts arrive on the same day, or two.

Black Tern by Lawrence G Baxter
So this weekend enjoy the summer migrants already on territory, look out for the mass arrival of Swifts, which can often be accompanied by Black Terns as they feed over large waterbodies, and if the chance arises, go hunting for grounded migrants at the coast. And, even though the winds have turned northerly it is always worth keeping an eye out for southern overshoots - Black-eared Wheatear could be on the cards.

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