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.

Friday, 31 August 2018

The first weekend of the autumn is looking good.

The weather forecast for this weekend should provide plenty of opportunity for migrant birds wanting to get moving and for those birdwatchers in search of them.

It isn’t going to be a classic forecast for continental migrants to get drifted here but it does have some promise. High pressure will be over Scandinavia for at least the next day or two, which will bring a hint of easterly airflow towards Britain and, any birds tempted by the good conditions to the north east of us might find themselves over the North Sea and heading towards our shores.

Red-backed Shrike by Neil Calbrade

At this time of the autumn we could be looking at the arrival of Wheatears, Whinchats and Redstarts, and perhaps the first Pink-footed Geese and Fieldfare. Amongst the scarce migrants, Barred Warbler, Icterine Warbler, Red-backed Shrike and Wryneck are all classic early autumn arrivals.
 Whinchat BirdTrack reporting rate

Redstart BirdTrack reporting rate

At sea, terns will also be on the move, Arctic and Common movements can be spectacular right now, and can include the occasional Black and Roseate Terns. These tern movements are inevitably followed by skuas and now is a good time to look out for the odd Long-tailed Skua amongst the Arctics.

Long-tailed Skua by Joe Pender

At least in the southern half of Britain the winds look to be light and at times from the north. This may well be the trigger for a large movement of Swallows and House Martins out of the country and we might all notice fewer of them around during next week.

The northern isles will be blasted by westerlies that have tracked across the Atlantic in the last day or so. These winds might bring something from North America with them, and if they do it might be something very special this early in the season. Of the ten accepted British records of Yellow Warbler half have occurred at the end of August, with the most recent being a two-day bird at Portland, Dorset in 2017.  From the east the only 2 records of Little Whimbrel have been at the end of August, fingers crossed for a third!

Scott Mayson and Paul Stancliffe

Friday, 27 July 2018

Autumn here we come

It seems a shame to mention the autumn whilst we are enjoying an amazing summer but autumn migration is gathering pace already. All of the BTO satellite tagged Cuckoos had left the UK by the end of June but since leaving some of them have had a rapid migration south; five have already successfully crossed the Sahara, you can follow all fourteen tagged birds here.


Swift numbers are beginning to build at coastal migration watchpoints as they too begin the long journey south, along with a few Swallows, House Martins and Sand Martins. The first warblers are also on the move with Willow and Sedge leading the way, and a few Lesser Whitethroats too. Many of these warblers will be this year’s young and will have nice fresh plumage and will stand out from the more worn looking adults.

Swift occurrence falling in BirdTrack

The most obvious migration happening right now is that of the waders and numbers will continue to build over the next few weeks. Early July saw Knot, Redshank, Spotted Redshanks and Bar and Black-tailed Godwits on the move but these have now been joined by Curlew and Green and Common Sandpipers, along with a few Whimbrel. It won’t be long now before the stints and Wood Sandpipers move too. A westerly airflow at this time of year can also produce the occasional American wader such as White-rumped, Pectoral or Baird’s Sandpiper and maybe something rarer like a Wilson’s phalarope!

Wilson's Phalarope by Andy Mason

Balearic Shearwaters, which breed in the Mediterranean, migrate to spend the autumn in the Bay of Biscay and the English Channel. Seawatching along the south coast at this time of year can produce good numbers especially during strong onshore winds. Occasionally birds make it further north and in to the North Sea.  A handful of Great Shearwaters and Wilson’s Petrels have also been seen off southern Ireland and in the southwest approaches, these will be making their way south to breed on remote South Atlantic islands.

Balearic Shearwater by Joe Pender

From the weather forecast it seems that the fairly settled weather will be with us for a little longer yet, however, during the next few days there are a few weak fronts that will cross the Atlantic. This should provide the right conditions for those seabirds that are crossing the Atlantic too and we ought to get a few more records of the large shearwaters and a few more Wilson’s Petrels too. The first Sabine’s Gulls might also put in an appearance as winds straight out of the Labrador Sea head this way too.

Paul Stancliffe and Scott Mayson

Thursday, 12 July 2018

Return migration is under way


July is a fantastic month for birding. Some species will have already finished breeding and will be making their way south with this years offspring to their wintering grounds. This can bring lots of rare and exciting birds to the UK- particularly around the coasts, but also to some inland locations.


Spotted Redshank by John Harding/BTO

The majority of the return migration happening at this time of year involves waders. First come the failed breeders, then the adults that have successfully bred, and then finally the young who have to navigate their way to the wintering grounds with no previous experience. Species whose numbers will increase over the next couple of months include Green Sandpiper, with the BirdTrack reporting rate almost doubling in the last two weeks, Greenshank, and Common and Wood Sandpipers. Numbers of Ruffs reported this week were also higher than average, possibly an indication of a poor breeding season, and are set to increase further until late August. Spotted Redshanks are one of the first waders to return with some birds heading back in late June and throughout July and in to August. Interestingly, the male Spotted Redshanks stay to raise the young in Scandinavia whilst the females set off earlier- a reversal of the typical gender roles in birds. Most of the males and young leave Scandinavia in the second half of July.

BirdTrack Green Sandpiper reporting rate graph

Our Swifts didn’t arrive on time this year, and whilst many of us were concerned that they wouldn’t return, they gradually appeared about two weeks late and increased to near-normal reporting levels compared to recent years, although still a little below the historical average. Mixed groups of Adults and young can be seen gathering over towns and cities before they depart for the winter. It will be a shorter stay this year, but at least they did come eventually!

Little Gulls by Andy Mason

Another species increasing at many coastal sites right now is the Little Gull: this species should be searched for in any gull flock, where its small size makes it stand out. At some regular sites, such as Hornsea Mere in East Yorkshire, triple figures have been noted. This species also has a tendency to occur at inland reservoirs and lakes where it can be seen hawking over the water, often dipping down to take insects from the surface. In July and August, Yellow-legged Gulls from the Mediterranean reach the UK as they disperse around the continent, providing birders with quite an identification challenge. Numbers of UK reports of this species have more than doubled over the last week and they are still rising, so this really is the time to scan gull flocks for these too.

BirdTrack Yellow-legged Gull reporting rate graph

Scarcer birds being noted currently include Spoonbill and Roseate Tern. The Roseate Tern is a scarce breeding bird within the UK and the birds being reported away from the breeding locations at this time of year will be a mixture of failed breeding birds from the UK and those from colonies further afield, soon they will be leaving our coasts for those of West Africa. Although Spoonbills can be seen here in all months of the year, many family groups visit the UK in July, right after breeding, look out for younger birds with pale bills and black wingtips.

It’s also worth mentioning Cuckoos. The adults have left the UK already as they have no parental responsibilities they are able to leave early. Two of the satellite-tagged Cuckoos (Victor and Bowie) have already crossed the Sahara Desert! The other tagged birds are currently in Spain and France, with one on an island in Croatia. The latest to leave the UK, Carlton II, left on the 2 July - this goes to show just how quickly Cuckoos can leave the country after breeding. You can follow them all as they make their way south.

Joshua Carter
BTO Work Experience


Thursday, 31 May 2018

Has the 2018 spring migration come to an end?


There is a general feeling that numbers of some of our long-distance summer migrants are still on
the low side, despite an arrival of birds in the easterly airflow at the weekend. Up until the last few
days birds such as Swift, House Martin and Swallow were indeed running late with numbers
looking poor too, but with suitable conditions during the Bank Holiday weekend they have caught
up somewhat. However, it is looking unlikely that they will reach their historical averages on the
BirdTrack reporting rate graphs.
Reporting rate graph for House Martin

Reporting rate graph for Swift

Reporting rate graph for Swallow

Even though we are at the end of May there is still time for a few migrants to arrive. We could
still see birds such as Spotted Flycatcher on the move, and maybe a last pulse of Swifts, although
if we don’t see the latter in the next week it is difficult to see any more arriving after that and it
might just be a low year for Swifts. Nightjar is one of the last of our migrants to arrive and now is
a good time to come across one at a daytime roost. On migration they don’t always pick the best
site and can be seen almost anywhere.
A day roosting Nightjar. Scott Mayson

Quail is a very hit and miss bird in Britain, with huge variation between years but in some years
we see hardly any at all until the first week of June. On any warm, still evening during the next
couple of weeks it is worth getting out and listening around the edge of cereal fields and listening
out for the distinctive ‘wet my lips’ call of the Quail.
Reporting rate graph for Quail, now is the time of year to listen for them.

The weather looks like it is forecast to be all over the place for at least the next four or five day
but does include a continuation of easterly airflow for the next day or so before a period of light
winds from the north west. For any birds still held up this should provide them with a window of
opportunity, and we might see a small movement of House Martins and Swallows. We could also
see some waders on the move, such as Greenshank and Wood Sandpiper. This is also a great time
for rarer wader, Terek Sandpiper could be on the cards but a Marsh Sandpiper would do nicely.
Paul Stancliffe

Scott Mayson

Friday, 27 April 2018

Mixed spring continues

To say this spring has been a mixed bag is a bit of an understatement with the balmy summer like conditions that spread across much of the country last week adding yet more variety. Temperatures soared well above average as a pulse of warm air, originating from North Africa, pushed up from the south. As would be expected this opened the door for several of our summer migrants to finally reach Britain and Ireland in good numbers.


Nightingale by John Spaull


Many areas recorded their first Nightingales, Cuckoos, Common Terns, and Lesser Whitethroats for the year as clear nights and a tail wind provided the push they needed to continue northwards. Indeed, Lesser Whitethroat arrived in such force that they were recorded way above their historical average, as the BirdTrack graph shows.

Lesser Whitethroat BirdTrack reporting rate


The better weather also meant two of the BTO satellite tracked Cuckoos made it back, with Selborne arriving on the 14th April and PJ back on the 17th April, fine out more here.
However, some traditional early arrivals such as Wheatear, Sand Martin and Little Ringed Plover are still lagging behind as shown in the BirdTrack graph below.

Little Ringed Plover BirdTrack reporting rate

It is probably still too early to draw conclusions as to what is causing this reduction in numbers, could it be that they were caught out by the cold weather that stretched across Europe earlier in the year and succumbed to the elements, or is it they are just taking their time?

Several of our winter visitors, like Redwing and Fieldfare, also took advantage of the southerly wind and clear conditions to depart for the summer months to their breeding grounds in Scandinavia and across Russia, with reports of both species down on previous weeks. By the end of the month the last of the wintering wildfowl, including White-fronted Goose, will also have departed.

Spotted Flycatcher by Edmund Fellowes


Spring migration is a protracted event lasting several weeks as birds head north in waves, now is the time to look for those species that migrate latter, so keep any eye out for Turtle Dove, Spotted Flycatcher, Roseate Tern, and Hobby. This is also the time of year that many species of wader start to pass through Britain and Ireland and species to look out for include Wood Sandpiper, Little Stint, Spotted Redshank and Ruff, many of which will be attaining their fine summer plumage.

Kentish Plover by Scott Mayson


With unsettled weather and a mixed wind direction forecast for the coming week, migration is likely to be curtailed once again with birds remaining further south waiting for the weather to improve before heading northwards again. Any better weather however could see the first arrival of those later migrating species with the added possibility of something more unusual mixed in like Kentish Plover, Golden Oriole, Red-backed Shrike, or Sardinian Warbler.