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 20 September 2018

Mixed bag of migrants

With a turbulent run of weather forecast for the coming week it makes predicting what will be migrating rather interesting shall we say. As deepening depressions rattle their way across the Atlantic they bring strong westerlies to our shores and periods of heavy rain. These weather systems cannot only dump large quantities of rain but can also provide us with a smattering of transatlantic vagrants, such as American peeps (or sandpipers as we know them) and maybe a rare 'Yank' warbler. Pectoral Sandpiper and Semipalmated Sandpiper have already made landfall in the UK this year but are likely to be joined by more individuals as well as the possibility of other species such as Least Sandpiper or Killdeer.
Strong westerlies can make for good seawatching conditions along the west coast with species such as Sabine’s Gull and Long-tailed Skua mixed in with the more expected Arctic and Pomarine Skuas and Kittiwakes. Sometimes these species are forced further inland by the strong winds so any reservoirs or large lakes are worth checking.

Sabine's Gull - Moss Taylor

As these weather systems make their way across the UK they will start to draw in a northerly and easterly airflow, opening the door for another suite of birds to arrive. For many birdwatchers this time of year is synonymous with Yellow-browed warbler, once the preserve of twitchers this is now an expected migrant with several hundred birds turning up in a good year. No longer is it just a coastal bird either, with individuals being found with greater regularity at inland sites. At this time of year any wind direction with a hint of east opens the possibility of something ‘off the radar’ turning up from the far east and have include Thick-billed Warbler, Brown Flycatcher and Yellow-browed Bunting.
For those species that arrive here for the winter northerly winds will aid their migration and numbers of Pink-footed Goose should increase and other wildfowl such as Shoveler, Wigeon and Teal should also arrive in ever growing numbers.
Reporting rate for Shoveler from BirdTrack

Waders will also be on the move as this years young, which typically migrate after their parents, start their first migration to wintering grounds, Bar-tailed Godwit, Knot, Turnstone and Sanderling can often form large groups and can turn up anywhere.

Sanderling - Jill Pakenham

Friday 14 September 2018

Migration reaching the peak period

Mid-September to mid-October is peak autumn migration time; this is the period when most birds are on the move, both in and out of the country. It has been estimated that at this time as many as 50 million birds could be on the move.

Meadow Pipit BirdTrack reporting rate

Right now Meadow Pipits and White Wagtails should be moving in force. However, the weather forecast for the next week doesn’t look very conducive to a large movement of any of these birds. We have largely been in westerly airflow for over a week now and it has turned up a few North American birds, White-throated Sparrow on Foula, Shetland, being amongst the highlights. It is difficult to see if this will continue over the next week, Hurricanes Florence, Joyce and Helene are really stirring up the weather in the Atlantic. It does look like the northern half of the country will remain in westerly airflow for longer than the southern half, with air being drawn out of the Labrador Sea bringing the possibility of a few more North American waders, Wilson’s Phalarope and Short-billed Dowitcher could be on the cards.

Whinchat by Mike Weston

In amongst this dynamic weather there will be high-pressure to the south for a little while resulting in fairly calm conditions over the channel, this will allow departing birds to get a move on and we could see hirundines make their last big movement of the year over the weekend, along with a few Yellow Wagtails and Whinchats.

Yellow-browed Warbler by Andy Mason

Even though we have already recorded our first Yellow-browed Warblers (they seem to be getting earlier and earlier) birds wanting to cross the North Sea from the north will have to wait a little longer, and it might be another week or more before we start to see arrivals of Redwings and Chaffinches and movements of Linnets and Redpolls.

Leach's Petrel BirdTrack reporting rate

It looks like the western half of the country will be the place to be. Sabine’s Gulls, Grey Phalaropes and Leach’s Petrels might all put in a performance, along with a few skuas and divers.