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, 5 February 2016

Storm driven birds

After a short cold spell in mid to late January, which brought frost and some snow to most areas, Atlantic weather patterns have reasserted themselves. A procession of storms has affected Britain and temperatures have reached double figures again. It feels much more like autumn than winter.

At this time of year many birds are settled on a winter site, with the largest movements undertaken being those from roosting site to feeding site. However, the storms have stirred a few birds up. Here in Thetford, Norfolk, there has been an obvious passage of Common Gulls during the last couple of days, presumably storm driven birds. There have also been several records of Kittiwakes in inland counties, including Surrey and Northamptonshire.

Kittiwake by Edwyn Anderton

In general, it has been a very good winter for gulls, with more than 20 species recorded, including the likes of Ross's Gull and Glaucous-winged Gull. It has also been a good winter for Caspian Gulls, with the reporting rate on BirdTrack well above average so far. The two large "white-winged" gulls, Iceland and Glaucous Gull, have also been noted on more complete lists submitted to BirdTrack in 2016. 

Reporting rate of Caspian Gull on BirdTrack
Intriguingly, two Franklin's Gulls have been found in our area in the last ten days. The species winters in the Caribbean and South America and is only rarely recorded north of Florida in winter. Have "our" two Franklin's Gull been swept across the Atlantic by one of the recent storms or have they been hiding unseen in gull flocks since the autumn and only now been discovered by birders?

The stormy conditions appear to have displaced divers in the North Sea, with some good counts of Red-throated Divers passing Spurn, East Yorks. Auks, mainly Guillemots have also been a feature, passing sites along the west coast in good numbers. Presumably, when conditions ease many of these birds will begin to make their way to their breeding colonies, but for now riding out these storms seems to be the order of the day.

Looking ahead, a further storm may affect the south coast of Britain on Monday, potentially bringing some more seabirds to inshore areas.

Paul Stancliffe and Stephen McAvoy

Friday, 15 January 2016

Cold weather and storms stir things up

Winter has arrived at last with some snow and frost in most parts of Britain in the last day or two. The colder weather is expected to stay with us into early next week at least, so we may start to see waterbirds such as Pochard, Tufted Duck, Goldeneye and Smew on the move as ponds and smaller lakes start to freeze. Already on the move are Bewick's Swans, which have been tracked moving west ahead of the cold weather in continental Europe. These new arrivals will certainly push up the current number of wintering birds (whose numbers may be down by 50%). Similarly, goose movements included a small arrival of European White-fronted Geese on the east coast, including six on the BTO's Nunnery Lakes reserve earlier this week.

Two White-fronted Geese at the Nunnery Lakes (Nick Moran)

The typical winter thrushes - Redwing and Fieldfare, are currently being reported well below the historical average on BirdTrack. This may change quickly as favoured feeding areas are covered in snow and frost and the birds are forced to move to new areas in search of food.

Reporting rate of Redwing in BirdTrack in 2016

Stormy conditions have been a feature of the winter and some strong south-easterlies at the start of January resulted in a wreck of seabirds, mainly Little Auks and Shag in northern England and eastern Scotland. There have also been an increase in the number of Great Northern Divers reported from inland water bodies.

Looking ahead, the current cold snap appears to last at least into the middle of next week and the current signs are that there will be a return to milder conditions for the rest of the month.

Paul Stancliffe and Stephen McAvoy

Tuesday, 22 December 2015

Stopping short

With the very mild weather that has been a feature of this winter also being experienced in central Europe, it appears that quite a few of our winter visitors are here in smaller numbers so far.

After an initial rush of migrants in late October and November, reports of Fieldfare and Redwing have tapered off, with reports on BirdTrack below average so far this month.

Reporting rate of Fieldfare on BirdTrack

Waxwings have arrived in small numbers so far, with several highly mobile flocks reported along the east coast. Wildfowl also appears to be a little thinner on the ground with Bewick's Swan, Bean Goose, Pintail, Pochard and Tufted Duck under-represented this winter. Most appear to be staying further north and east as water bodies remain ice free.

Of course there are other factors than just the weather to consider. Food is the most important component in deciding whether to stay or go. The weather may be mild, but if there is a failure in the food source - Beech for Brambling or winter berries for Waxwings and thrushes for example - then the birds will have to move on. Migration is always a hazardous, especially if it involves a sea crossing, so stopping the migration short where conditions are suitable seems a good option.

Currently there are still a handful of Swallows being reported and these birds are effectively short-stopping. However, these may still move further south if the availability of flying insects is reduced. It does seem unlikely that they will fly as far as southern Africa though - a few spend the winter in southernmost Portugal and Spain. It is anybody's guess where the Swifts reported from Kent, Cambridgeshire and elsewhere in the last ten days have come from and where they might be going to.

Iceland Gull (Nick Moran)

Low pressure systems crossing the Atlantic look set to dominate the weather with even more wet and windy conditions prevalent at least into the new year. Some models show a particularly strong weather system towards the end of the month with strong winds reaching from north-western Greenland and north-eastern Canada all the way to western Britain and Ireland. Similar conditions have brought good numbers of Iceland and Glaucous Gulls to our shores, as well as rarities like Ross's and Ivory Gulls.

Paul Stancliffe & Stephen McAvoy

Friday, 4 December 2015

Goldfinches still on the move

Goldfinch migration has been one of the highlights of this autumn, and it is still ongoing. Usually, it should have drawn to a close by this stage, with birds arriving at their wintering sites in southern Europe and North Africa. But they are still on the move and being counted at some migration watchpoints - 280 were counted moving past Hengistbury Head, Dorset and 520 past Portland, Dorset in the last few days.

The recent wild weather seems to caused some diver movement along the coast, with many sites noting Red-throated and Great Northern Divers passing offshore. The BirdTrack graph shows a notable spike in Great Northern records in mid-November - possibly birds arriving from elsewhere? Some birds also moved close to shore in search of sheltered waters, giving excellent views.

BirdTrack reporting rate for Great Northern Diver

Great Northern Diver (Nick Moran)
A few Swallows are still hanging around, braving the recent poor weather. However, there have no further sightings of House Martins since the end of November. One or two Yellow-browed Warblers are still being noted in western Cornwall and may stay on if the weather remains mild in the next few months.

After a rush of sightings in October and early November, Brambling and Great Grey Shrikes appear to have moved on with reporting rates about average on BirdTrack. Waxwing numbers appear to be building slowly, with small flocks noted in East Anglia and along the north coast in recent days. More settled conditions with winds coming from the east would probably encourage more to arrive, but the weather models are currently predicting no let-up in the storms arriving in off the Atlantic.

Paul Stancliffe and Stephen McAvoy

Friday, 27 November 2015

Late Season Seabirds

It has been an interesting week, both weather-wise and in the birds that are on the move. The last few days have been dominated by front after front coming across the Atlantic, bringing unsettled conditions with them. Rough seas at this time of year will always stir up some seaduck movement and that appears to have been the case this week.

Goldeneye, Scaup, Eider, Long-tailed Duck and Common Scoter have all been well represented past coastal watchpoints. The BirdTrack reporting rates for all five of these of these species, as well as Velvet Scoter showed a noticeable increase.

BirdTrack reporting rate for Velvet Scoter

Velvet Scoter in flight showing distinctive white secondaries (Photographer: Sam Creighton)

The weather also stirred up a few skuas, particularly Great Skua and to a lesser extent, Pomarine too. The best count was of 105 Great Skuas past Titchwell, Norfolk on 21 November and very good count of 73 "Poms" past Spurn, East Yorkshire on the same day.

Having predicted an arrival of Little Auks into the North Sea in last week's blog, we were not to be disappointed. While it wasn't one of the largest movements of Little Auks ever recorded, there were still impressive counts at some sites. The 602 seen passing the Farne Islands, Northumberland last Saturday were particularly noteworthy. Virtually every site along the east coast of Britain recorded at least one or two, with a handful noted on the west coast and in Ireland.

Little Auk (Dawn Balmer)
Further seabirds of note included Grey Phalarope, Long-tailed Skua and Sabine's Gull. Several of the former were noted at inland sites, with one particularly obliging individual on Farmoor Reservoir, Oxfordshire present in the last few days.

Moving away from seabirds, Swallows haven't quite disappeared just yet, with around 20 reports from all around the country in the last week. Keeping on the summer migrants theme, three Lesser Whitethroats were also found - only time will tell if these are birds that have settled into their chosen site for the winter.

Lesser Whitethroat (Stephen McAvoy)

The surface pressure charts for the next few days show that we will still be in the middle of westerly airflow. However, on Saturday, the winds will be pretty much uninterrupted from the east coast of North America to the west coasts of Britain and Ireland. Is the American Bittern found in County Cork a herald for other vagrants from the west? Killdeer and American Robin seem likely candidate species for this time of year.

Paul Stancliffe and Stephen McAvoy

Friday, 20 November 2015

It's getting late

Even though we have now passed the mid-November mark, there is still a feel of autumn in the air and many birds are still on the move.

Woodpigeons were the biggest surprise of the week, with large numbers recorded in the west and along the south coast. A total of 25,00 were logged at Portland, Dorset on the 16th and almost 50,000 in Gwent on the 20th. The latter figure pales in comparison to the 210,000 counted at the latter site on the 5th of November 2014.

Woodpigeon thinking about migrating (Nick Stacey)

Finches were also still on the move, mostly represented by Goldfinches. It feels a little late for hundreds still to be moving over coastal watchpoints, but that has been the case at several sites this week. 399 Goldfinches and 278 Siskin passed Spurn, East Yorkshire last Tuesday for example.

The latter site also had 154 Whooper Swans flying south two days latter and the species is being reported in above average numbers so far on BirdTrack this week.

Reporting rate of Whooper Swan on BirdTrack

Woodcock have finally made their presence felt too; 69 were counted in a small area on Fair Isle, Shetland on the 17th of November, which was the highest count of the autumn. The wardens estimated there could well have been a triple-figure count with better coverage.

It has gone a bit quiet again on the Waxwing front following the arrival of birds earlier this month. The only reports were of two two in Argyll on Saturday and another three on Shetland on Wednesday. Any excuse to post more Waxwing photos though!

Waxwing by Steven Mcgrath

Looking at the weather for the next few days, Saturday appears to be the most interesting day. Strong northerly winds are forecasted for the western North Sea bringing an arctic chill to the east coast of Britain. Similar conditions in the past have resulted in good counts of Little Auk and small flocks have been reported in the last few days. Ducks, swans and geese are likely to be on the move as well, as will the last remaining Swallows (two at Spurn on 20th) and House Martins.

Paul Stancliffe and Stephen McAvoy

Friday, 13 November 2015

"Plague Birds" bring joy

It might be the fact that we are in the middle of a prolonged spell of westerly weather, or that we are now approaching mid-November, but migration has been pretty slow during the last week.

Finches have had their moments with some respectable counts from coastal watchpoints. This included 1,078 Siskin, 771 Goldfinch, 113 Chaffinch, 202 Linnet, 79 Twite, 169 Lesser Redpolls, 15 Brambling and 18 Greenfinch counted moving through Spurn, East Yorkshire on 10 November. A couple of days previously around 2,500 finches (mainly Goldfinch) moved over Portland, Dorset. Thrushes have been less spectacular and it seems that there might still be a large movement of Starlings across the North Sea in the wings; we don't seem to have had any large arrivals so far this autumn.

Goldfinch by Stephen McAvoy

Woodpigeons are an often overlooked migrant, but autumn passage can be spectacular for the sheer number of birds involved. Several thousand were observed flying over Bristol on Thursday, as well as over Portland, Dorset on the same day.

Last week also saw the first reports of Waxwings* from Britain and Ireland this autumn. Given its proximity to Scandinavia, it was no surprise that the first birds appeared on Shetland, with at least two present on Mainland on 5 November. Over the next few days, Waxwings were found in Durham and Aberdeenshire and two birds even made it as far west as Northern Ireland on Wednesday. Hopefully this is only the start of a good winter for these amazing birds!

Waxwing by Adrian Dancy
The spell of very mild conditions associated with the southerly winds might have contributed to a late run of hirundines and swifts. This included several more reports of Pallid, Common and unidentified Common/Pallid Swifts from Kent, Northumberland and Warwickshire amongst others. Late Swallows and Sand Martins were reported as well, including one House Martin on the Outer Hebrides.

After a spectacular couple of weeks, the Yellow-browed Warbler invasion is slowly petering out, but the species was still being reported on a respectable 0.3% of all Complete Lists reported on BirdTrack.

Yellow-browed Warbler reporting rate on BirdTrack

Rarity of the week was undoubtedly the very unexpected Crag Martin in Chesterfield, Derbyshire present from last Sunday onwards. Giving great views flying around the centre of the town, this would only be the 8th or 9th confirmed record for Britain.

Looking ahead, migration is starting to slow down, but it is not quite over yet. Bewick's Swan, Bean Goose, Goldeneye, Pochard and Tufted Duck all peak in mid-November. The weather looks set to remain stormy with the remnants of Hurricane "Kate" likely to pass NW Ireland and Scotland on Sunday, with more low-pressure systems crossing the Atlantic close behind it. For Sunday, the charts look remarkably similar to the one on the 10 November 2012 when a Cedar Waxwing was found on Belmullet in western Ireland.

*The Dutch name for Waxwing is Pestvogel, which translates as "Plague Bird".

Paul Stancliffe & Stephen McAvoy