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 25 October 2013

West might be best

The southerly airflow of the last week or so resulted in a small influx of Pallid Swifts and Hoopoes, and during the periods when the wind was light the first large movement of Starlings across the North Sea, accompanied by smaller numbers of Chaffinches, Bramblings and thrushes.

Brambling by Tommy Holden

This week things are going to be very different indeed. A fast moving low pressure system is due to hit us on Monday, bringing very stormy weather with it. This will firmly put the brakes on any movement across the North Sea, and indeed anything trying to leave the UK too.

Upland Sandpiper by Joe Pender

So, it will be all eyes to the west this weekend and into the early part of next week, with the chances of North American birds turning up being high. Chimney Swift, Cliff Swallow, Yellow-billed Cuckoo and Upland Sandpiper are all possible. We may see something even more exciting from that direction, with Britain’s second ever Cape May Warbler currently on the Shetland, perhaps we might see Britain’s second ever Yellow-throated Vireo too.

Golden Plover by Tommy Holden

Once the storm leaves our shores the north of the UK will for a short while be bathed in a north-westerly airflow. This could result in the first large arrival of Whooper Swans, Icelandic Redwings and any laggardly Golden Plovers that are still left that far north.

Friday 18 October 2013

Look to the south, and the south-west, and possibly the north and north-east!

The weather forecast over the next few days puts us largely in warm air from the south, from as far south as central Spain, and so we might expect one or two birds from that direction. During the last few days there has already been a Pallid Swift in Cleveland, a new Purple Heron in Shetland and a Hoopoe on the Farnes, and more of this is on the cards. We could see one or two more Hoopoes, Woodchat Shrike and maybe a Red-rumped Swallow.

Swainson's Thrush by Bryan Thomas

The weather forecast is a little more complicated than it seems; as the next couple of days unfold a low pressure system will cross the Atlantic bringing south westerlies with it and, although it isn’t a very deep low, or particularly fast moving, it could bring a North American bird or two to the Isles of Scilly; my money would be on a thrush, possibly Swainson’s. As the low spins across the UK, Shetland and the north-east will be bathed in an easterly airflow, just as high-pressure begins to build over Scandinavia. This should definitely result in a fresh arrival of birds; although for Shetland we are now quite late in the season, easterlies at this time of the year have the capacity to bring something very rare with them – Rufous-tailed Robin, Yellow-browed Bunting sort of rare!

Reed Bunting by John Harding

What will this mean for the common migrants still making their way south and west? In between this mix of weather there will be times when the winds become light, from whichever direction they originate. During these spells of lighter winds, migrants will move and we could see finches (mainly Linnet and Goldfinch but Redpoll should also feature), Reed Buntings, Skylarks and thrushes (mainly Redwing, Song Thrush and Blackbird), and Starlings moving in good numbers. Now would be a great time to start the BTO Winter Thrush Survey to help us find out where they go and what these birds do, when they get here.

Brent Geese on the move by Andy Mason

Offshore, the number of Brent Geese on the move will increase and we should also see Red-throated Divers too, and, if we look at the BirdTrack reporting rate, the Whooper Swan arrival should peak in the next week.

Whooper Swan BirdTrack reporting rate

So, even though the weather doesn’t look ideal for a large arrival of birds from the east, or the west, or even the north, there should definitely be birds of a southern flavour, and there ought to be something for everyone this weekend.

Paul Stancliffe

Friday 11 October 2013

What a difference a week makes

I spent last weekend with BTO’s Head of Membership & Volunteering Ieuan Evans, at the Dorset Birdfair, in the spectacular setting of Durlston Country Park. As we left our accommodation there was light drizzle in the air and lowish cloud and a light, warm south-westerly breeze blowing but on arrival at the park, the ‘rain’ had stopped and the cloud lifted and the day turned very summer-like. Setting up our stand, overlooking the sea, hundreds of Swallows were pouring over our heads, interspersed with flocks of Goldfinches.

Linnets by Martin Cade, Portland Bird Observatory

As the morning progressed the Swallows continued to move and were joined by smaller numbers of House Martins and a few Sand Martins. The finches became more varied with flocks of Chaffinches and Linnets joining the Goldfinches. During the early afternoon, Skylarks began to move, in flocks 20-30 birds strong, and three Woodlarks arrived from the east. The movement continued all day, and involved around 2-3,000 Swallows, 3-400 House Martins, 500 Goldfinches, 100 Linnets and 2-300 Chaffinches. A small number of Mediterranean Gulls were  moving offshore. 

We were also treated to some fantastic southern insects, the highlight of which had to be nine Convolvulus Hawkmoths, two Crimson-speckled Footmen and a Bloxworth Snout. The bonus was that one of the BTO guided walks  coincided with a swim-past by a pod of Bottle-nosed Dolphins that were moving east close inshore.

Ieuan photographing Convolvulus Hawkmoths

Fast forward a week and we are back in Norfolk, the temperature has dropped around 10 degrees, the wind is storm-force and coming from the north-east. With high-pressure over Scandinavia and easterly airflow across the North Sea, Redwings have begun to move in force – over 33,000 were counted moving over the Pinnacle, Sandy, Beds during the morning of the 10th. The high-pressure is forecast to settle over Scandinavia for the next few days, so this figure could be eclipsed as more Redwings make the move south. It is estimated that around three-quarters of a million Redwings spend the winter here, so there are plenty more to come. Blackbirds and Starlings should also begin to arrive in number, along with the first real flush of Fieldfares. The finches will continue to move but there could be some good sized flocks of Brambling and Siskin to count.

Little Auk by Andy Mason

Along the east coast a seawatch should also prove fruitful. Skuas; Great, Arctic and the odd Pomarine should weigh-in, and we could see an arrival of Little Auks in the north-east. On the duck front, Wigeon and Teal could put on an impressive show this weekend as they arrive from the continent.
If I were to predict a rarity, Red-flanked Bluetail would be favourite, although nowadays it is more a scarcity than a rarity. There could be one-or-two Radde’s Warblers found and although it is a little early, Pallas’s Warblers could put in reasonable showing. Ieuan has suggested Nutcracker, and he is definitely in with a shout. 

Paul Stancliffe

Friday 4 October 2013

It's all happening out there!

Sitting behind a desk, gazing at a computer screen, it can be hard to get a handle on what's happening outside the window, let alone further afield! However, having immediate access to the powerful combination of BirdTrack, Twitter, the bird news services and a range of weather websites – not to mention the plethora of BTO staff 'bird brains' and thousands of volunteers ready to share their observations – does have its advantages. This week's news has been as interesting and varied as ever, ranging from tales of House Martin chicks still in the nest in north Cumbria and Ireland to the first Radde's Warbler of the autumn, on the Isle of May in Fife.

House Martin chicks still in a nest in Co. Fermanagh, Ireland on 2 October
David Morrow

High pressure was settled over the continent to the east and north of Britain into the early part of this week, with light easterly winds continuing to drift scarce passage migrants like Yellow-browed Warbler and Red-breasted Flycatcher in our direction. Conditions were also reasonable for the departure of hirundines, warblers and other small passerines at the start of the week, though the wind increased in strength as the week wore on and is forecast to swing to the southwest, offering less conducive conditions for birds departing across the Channel. However, as the high pressure to the east meets the low pressure from the west and creates more unsettled weather, it may ground any migrants that have left the continent onto the east coast of UK, and the conditions may still be good enough for some slightly bigger Redwing arrivals.

BirdTrack reporting rate for Redwing... due any day now!

It is worth looking out for White Wagtail too; they should also be on the move and can often migrate with thrushes. With Song Thrush and Redwing already beginning to appear and Fieldfare not too far behind, now is a great time to plan your first BTO Winter Thrushes Survey visit of the autumn.

A couple of low pressure systems are moving east across the Atlantic over the weekend and whilst they aren't particularly deep, could still bring a nearctic vagrant or two with them. Friday saw the discovery of a mega-rarity on Shetland, a Thick-billed Warbler, a species that breeds no nearer than the banks of the river Ob' in Russia, along with belated news of an equally rare species from at least as far to the west, a Cedar Waxwing that spent the last week of September in a garden on Tiree. On the basis that predictions are only remembered if they come true – and spurred on by Shetland's rare warbler (not to mention Norfolk's false alarm about a Rufous-tailed Robin) – I'll stick my neck out and say Siberian Blue Robin on Spurn and on the back of those low pressure systems crossing the Atlantic, a Least Sandpiper (or two) in Cornwall.