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.

Friday, 22 May 2015

Migration slowing down – or is it?

The weather has been such a mixed bag during the last couple of weeks it has been difficult to disentangle and work out what effect it has had on migrant birds. The almost autumn-like westerly fronts that have been tracking across the Atlantic do seem to have brought some Nearctic birds with them – Great Blue Heron, Hudsonian Godwit and Dark-eyed Junco are all incredible spring birds.

As the fronts have passed over Britain they have introduced sporadic southerly and south-easterly airflow, which at times has been quite productive. Spring 2015 will go down as a ‘southern herons’ spring, particularly in the south-west. If you were on the Isles of Scilly last week it was possible to see up to five Night Herons, two Little Bitterns, a Squacco Heron and a Purple Heron! It must have felt a little like being in southern Europe.

Squacco Heron by Derek Belsey

So, migration has continued apace but there are signs that it is slowing down; counts at coastal watchpoints are returning diminishing numbers. However, it does seem like some of the common migrants are still a little thin on the ground and that there are still plenty more to arrive. Perhaps we are in need of some warm southerly winds to test this out. Certainly here in East Anglia there seems to be fewer Cuckoos than were around last year and the BirdTrack reporting rate seems to reflect this nationally. Willow Warbler and Whitethroat are showing similar reporting rates, and if Spotted Flycatcher is to get anywhere near the BirdTrack historical reporting rate there are a lot more to arrive yet.

BirdTrack reporting rate for Cuckoo

Skuas have been on the move past the Outer Hebrides during the last couple of weeks; the highest count has been of 1,307 Long-tailed Skuas flying past  Aird an Runair, North Uist on 12 May, and accompanied by 353 Pomarine Skuas must have been an amazing sight.

Pomarine Skua by Joe Pender

Quail have begun to turn-up in small numbers. These enigmatic little birds can be quite common in some years and almost absent in others. As Quail can still turn up in early June, it is still a little too early to tell whether this will be a Quail year, or not.

So, what might we expect this weekend? Initially it looks like we will have light northerly winds at least on Saturday into Sunday morning, and again on Monday. At this time of the year these conditions can be quite productive. Migrants birds can and do migrate into light northerlies and if there is going to be a late push, Saturday and Sunday morning look good. On the rarity front, something from the south east is always on the cards this late in May – Red-footed Falcon is the obvious candidate but a spring male White-throated Robin would really set pulses racing.

No comments:

Post a Comment

Note: only a member of this blog may post a comment.