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, 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.

Thursday, 19 April 2018

Stop, start migration

This spring has been a very interesting one, so far. For the first few weeks it was definitely running late. Chiffchaff, Blackcap, Sand Martin and other early migrants were 2-3 weeks behind their normal migration pattern. Fast forward to the here and now and it is hard to believe migration is late at all. Those birds that should be arriving right now, including Cuckoo, Nightingale and Hobby, are arriving bang on cue.  In northern Britain some species have arrived early. In the last few days, Fair Isle has had its earliest ever Lesser Whitethroat and Dotterel.

Dotterel by Edmund Fellowes

This all goes to show how weather affects our long-distance migrants and how spring migration is a bit of a lottery; arrive here early and in an early spring the gamble may well pay off, this year it probably hasn’t; arrive here late and you might miss the best breeding territories and the strongest mate, this year you might be OK.

With southerly winds some of our early migrants have caught up and pretty much seem to be back on track, as seen in the BirdTrack Chiffchaff graph below. But what has happened to Wheatears? They are still way behind where they should be for this time of the year; check out its BirdTrack graph. It’s getting to the stage where we might consider something more sinister at play rather than just being delayed. Might there have been a problem in the winter quarters?

Chiffchaff BirdTrack reporting rate

Wheatear BirdTrack reporting rate

The forecast for the next few days is for south and south westerly winds, which will be particularly light over southern and central Europe. This should really open the floodgates for our migrants, both those making their way here and for those leaving. I still have Bramblings in my garden but probably won’t have by the weekend.

Brambling by John Harding

So, if you haven’t already heard a Cuckoo you could well do over the weekend, two of our satellite tagged birds are back, you can find more about them here. Keep an eye out for Hobby, and even an early Swift or two. Amongst these many of our migrants will become more obvious, Reed Warblers, Grasshopper Warblers, Whitethroats and Garden Warblers should all be seen and heard over the next few days. Tern passage will start to build too, with Common, Arctic and Sandwich Terns all on the move.

Black Kite by Jill Pakenham

With lots of birds on the move there is bound to be a few overshoots with them, the most obvious are Hoopoe, Purple Heron, Black Kite and Red-rumped Swallow, but we could also see one or two Sub-alpine Warblers and hopefully Alpine Accentor, one that hangs around for a couple of days allowing lots of birders to catch-up with it.
Paul Stancliffe

Thursday, 12 April 2018

Migration still slow

During the last week there has been an arrival of summer migrants, with most of the early arrivals represented. However, numbers still seem to be quite low. Although spring feels late this year the first Sedge Warblers have arrived bang on cue and Ring Ouzel has pretty much caught up.

BirdTrack reporting rate for Ring Ouzel

With that in mind it will be interesting to see how the next week unfolds. There is a good window in the weather on Friday going into Saturday when winds will be easterly turning southerly and light across the Channel and the southern North Sea. This should allow anything held up to move, at least those birds that have made it north of the Pyrenees. It looks like there will be a blocking weather front just north of the mountains that will probably stop any birds moving in to it in their tracks.

Pied Flycatcher by John Harding

So, what might turn up? Pied Flycatchers, Redstarts and more Ring Ouzels should definitely be a feature; in fact it might well be a Ring Ouzel weekend. We should see more Black Redstarts too and possibly one or two more White-spotted Bluethroats.

Cuckoos seem to pretty much on time too but if you haven’t heard one yet you could well do at the weekend. With any luck we should have our first satellite tagged bird back too, the closest is just over three hundred miles south of his Suffolk territory, so he might well make his move on Friday. You can follow him and four other tagged Cuckoos here.

Whitethroat by Amy Lewis

Right now we should be seeing Whitethroats, Willow Warblers, Yellow Wagtails and Tree Pipits either moving through or singing on territory; this could well be the case on Saturday morning. White Wagtail and Little Gull are classic birds for this time of the year in these conditions too.

Wryneck by Jill Pakenham

With easterlies forecast it is worth keeping an eye out for a Wryneck or two, especially if you plan on visiting the east coast, and who knows? We might be treated to a Pallid Swift too.

Friday, 6 April 2018

Migrants about to flood in

Spring migration has been a bit of a trickle so far, however, this is about to change. The forecast for the next few days, and into next week, is one of southerly and at times fairly light winds, the ideal recipe for migrants that have been held-up to finally arrive.

Chiffchaffs and Blackcaps should really be here in force now but as evidenced by the BirdTrack graphs they are running about two weeks late.

These aren’t the only birds running late as most of the early migrants seem to be held-up further south. The graphs for Swallow and Wheatear are just as revealing.

As we write this, birds are at last beginning to arrive, several Chiffchaffs and a single Willow Warbler are now singing on the BTO’s Nunnery Lakes, and the first singing Blackcap of the spring has just burst into song at the headquarters.

The winds on Friday are forecast to be coming from as far south as North Africa, which will almost certainly provide a window for some of our later arriving visitors to get here a little early; there is already a report of a Common Swift from Lancashire and the winds are only just turning south. During the next couple of days birds such as Cuckoo, Turtle Dove and Hobby should all be on the cards. The trickle of Yellow Wagtails, Tree Pipits and Ring Ouzels should also grow, and we should see the first push of Sedge Warblers.

With winds coming from so far south, overshoots will be inevitable, Alpine Swift, Hoopoe, Red-rumped Swallow and Black Kite are the classics but a showy Great Spotted Cuckoo would be much appreciated.

A flavour of migration further south has been given to us a by a friend who is currently working on a survey ship 8 miles off the North African coast around Agadir, Morocco. He has seen flocks of Pintail heading north, a trickle of Sandwich and Common Terns accompanied by Arctic, Long-tailed and Pomarine Skuas. 

Long-tailed Skua chasing Sandwich Tern
 by Andrew Williams

Swallows have also been on the move but the highlights have included Grey Phalaropes, a Hoopoe being mobbed by several gulls that managed to run the gauntlet and carry on north, and a Purple Heron that tried to land on the ship but failed and too continued north.

 Hoopoe off Agadir by Andrew Williams

Evading capture

Paul Stancliffe
Scott Mayson

Thursday, 15 February 2018

Finches on the move?

The last week has seen the number of Chaffinches, Goldfinches and Siskins build in a few BTO staff member’s gardens here in Thetford. It has been a very quiet winter for all three so we are almost certainly experiencing a movement of these birds through the area. Presumably these are birds that have been wintering south and west of here and are moving north and east in preparation for the forthcoming breeding season. The BirdTrack graphs for Chaffinch and Goldfinch show the upturn of both species well. It is interesting to note that Chaffinch is well below its historical average, probably as a result of fewer birds crossing the North Sea last autumn.

All of the satellite tagged Cuckoos that we are currently following have made a move north; Selborne currently leads the pack and has moved further west in the last couple of days into Guinea. In 2017 he crossed the Sahara on 25 March, having arrived in West Africa on 2 February. It is fascinating to think that along with the Cuckoos many of our summer migrants will already be on their way back too. House Martin and Swallow have already been recorded in southern Europe.
Follow the Cuckoos here as they make their way back.

Closer to home, Red-throated Divers are on the move, with double figure counts past several coastal watchpoints and Wigeon numbers are also beginning to build at east coast sites.

Red-throated Diver by Andy Mason

With lots of birds redistributing around the country now is a great time to look for rarer geese amongst the flocks of commoner species. Flocks of Pink-footed Geese are worth checking for Tundra Bean, and Red-breasted Geese have been known to associate with them too.

Iceland Gull by Scott Mayson

White winged gulls are also on the cards as they too begin to move back north, Iceland and Glaucous Gulls can turn up almost anywhere at this time.

Scott Mayson and Paul Stancliffe

Tuesday, 30 January 2018

Migration underway

It might only be the end of January and the days might still be short but some of our birds have already begun their spring migration. Fieldfare and Redwing have started moving north and east, with numbers beginning to build in eastern Britain. Siskins have started to turn up at garden feeding stations as they too make their way back north, and the first of the BTO satellite-tagged Cuckoos has begun the long journey back to the UK.

Cuckoo PJ spent most of the winter in Angola but since leaving there last week he has travelled 1,600 km (1,000 miles) north and is now in Cameroon. He should head west from here before once again turning north and crossing the mighty Sahara. You can follow him as he makes his way back home during the next couple of months.

Auks are also on the move and Guillemots and Razorbills could be back prospecting on their breeding ledges any day now. Look out for them at coastal watch points.

Guillemot by Sarah Kelman

One of the biggest surprises of the autumn 2017 migration was the unprecedented arrival of Hawfinches into Britain. The exact number is difficult to calculate as the birds are so widespread and mobile, but it is thought in excess of 1,000 birds have arrived here and that the true figure might even be as high as 5,000. The estimated breeding population is only 500 – 1,000 pairs, so this is an incredible increase. The BirdTrack graph shows how spectacular this arrival was compared to the historical average for the species, and they are still being seen across the UK. Some of the largest concentrations are currently to be found in Surrey, Sussex and Shropshire.

Hawfinch BirdTrack reporting rate 2017 almost quadrupled

It’s only a matter of time before the wintering geese and wildfowl begin to head north and east too. February is the peak month for Pintail, Goldeneye and White-fronted Goose all of which will be steadily heading to the breeding grounds in Northern and Eastern Europe. Male Goldeneyes at this time of the year can often be seen performing their display which involves throwing their heads backwards, then forwards – extending the neck as they do so – in readiness for the breeding season ahead. Other wildfowl will be getting in to flocks ready to depart when the weather is favourable, with some heading across Europe whilst others,such as Whooper Swans and Pink-footed Geese, will be heading to Iceland and Greenland for the summer months.

Scott Mayson, BirdTrack Organiser, and Paul Stancliffe, Media Manager