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, 28 April 2017

Migration about to spring into action - guest blog by Ben Porter

The nature of migration generally this spring has been one of sudden flurries followed by slow trickles. This week continued along much the same lines: a glorious weekend with a southerly airflow and wide isobars saw the floodgates open for northbound migrants to stream into the country. Coastal localities were inundated with Willow Warblers, Blackcaps and Wheatears, and species like Redstart, Sedge Warbler, Whitethroat, Ring Ouzel and Grasshopper Warbler took advantage of the passing weather front to move in from the continent. Then the traffic lights turned red: a complete flip in the airflow saw bitter northerly winds dominating for much of the week; temperatures plummeted into the single figures and flurries of snow and hail across the north of the UK further added to the week’s wintry feel.
Willow Warbler by Ben Porter

The calm conditions over the weekend made for some great arrivals here on Bardsey: bushes were brimming with Willow Warblers and Blackcaps; Grasshopper Warblers sent out reeling songs from the damper wetlands; Swallows and Sand Martins zipped northward overhead; and seemingly every grassy knoll and bank was topped with a Wheatear! Greenland-race Wheatears have been one of the dominating migrants on the island this week, their larger size and deeper orange belly contrasting with a flash of white as they alight with hard ‘chacking’ calls. An excellent arrival saw over 250 birds on the 20th, although the national reporting rate on Birdtrack still shows below-average occurrence. It looks like the pressure front next week is going to help these leucorhoa birds make their long-distance flights to the Arctic tundra via Iceland and Greenland.

Wheatears by Ben Porter
Wheatears by Ben Porter


Cuckoos and Turtle Doves have yet to make it over the Irish Sea to the island, although both species reached Scotland this week, with a Turtle Dove on the isle of Rhum and a Cuckoo in Lothian! Three of the BTO’s satellite-tagged Cuckoos are now north of the Pyrenees and should make the home stretch to join ‘Selborne’ with a brisk south-east tailwind in the next week. Keep up to date with their movements here

A smattering of colourful scarcities arrived in the UK this week, including Golden Oriole, multiple Hoopoes, at least three Bee-Eaters (one of which even paid London a visit!), White-spotted Bluethroats, Serin, Red-footed Falcons and the spring’s first Savi’s Warbler. We can expect to see plenty more of these overshooting continentals as we enter May, plus some non-passerine visitors such as Temminck’s Stints on inland reservoirs. Conversely, Waxwing numbers are likely to dwindle as birds continue to dissipate north-east – we still had around 600 birds in the country last week, although they were absent from Ireland, Wales and the South-west.

Whimbrels should arrive in earnest over the next ten days as we approach their peak spring reporting period. The numbers here on Bardsey Island are still below-average for the time of year. Contrast that to the national picture, and the reporting rate is slightly above the historical average, fast-approaching 7.5% of Birdtrack user’s lists. Keep an eye out for colour-ringed birds amongst migrating flocks: they are most likely to be from Iceland, but a few sites in the UK also carry out colour-ringing on these waders, including Bardsey Bird Observatory. Make sure you report colour-ring sightings and email the Iceland project (icelandwader@gmail.com) should you see any. It’s through anaylsis of ringing recoveries and recent satellite tracking that has revealed some impressive autumn movements of Icelandic Whimbrels from Iceland to North Africa. It’s also indicated that most birds on the east coast – both in spring and autumn – are likely to be Scandinavian.
Whimbrel ring recoveries from BTO. Whimbrel images by Ben Porter

Early May is one of the best times of year to catch up with trips of Dotterels as they touch down on hill tops and coastal spots en route to their breeding grounds. A scattering of birds have already been seen over the last week, including at favoured sites such as the Great Orme in North Wales. Lancashire’s Pendle Hill will no doubt host a few of these superb waders in the next few days.

So what of the week to come? A low-pressure system rolling in from the Atlantic over Saturday and Sunday will see the strong winds switching around to the south-east, which could provide the encouragement needed for migrants to move up through France and continue northwards in the UK. A widening of isobars and an area of high pressure over France and Iberia in the earlier part of the week should make for a good arrival of more warblers, chats and waders. Temperatures should climb a little higher too, which will hopefully encourage the invertebrate life to emerge and provide weary migrants with much-needed refueling!
Low pressure is due to arrive on Saturday - image from Met Office.


We’ve almost welcomed back the full complement of spring migrants as far as songbirds are concerned, although Spotted Flycatchers have yet to appear, and the peak arrivals of Wood Warblers, Pied Flycatchers, Yellow Wagtails, Garden Warblers and Lesser Whitethroats will probably occur over the next week or two given the promising outlook.
Spotted Flycatcher by Ben Porter
Spotted Flycatcher by Ben Porter

If you’re heading out over the weekend, listen out for the liquid gold song of the Nightingale – birds should be back on breeding territories very soon. The bright sunny weather forecast for early next week will be perfect for Common Swifts to scythe their way overhead in screaming flocks. If you haven’t already, why not consider fitting a Swift nestbox to your house? There is just enough time before they return! There are plenty of tips at www.swift-conservation.org

The reporting rate for Common Tern and Arctic Tern is on the increase, and the strong winds this weekend might make seawatching a productive option to spot flocks passing by. You might also be in with a chance of seeing Pomarine, Arctic and Great Skuas passing the coast. Rarities in the coming week could take the form of more overshooting continental migrants such as Black-Winged Stilts and Golden Orioles, although the south-easterly wind might favour perhaps a Collared Flycatcher, Citrine Wagtail or Red-throated Pipit even on the east coast.
Red-throated Pipit by Ben Porter
Red-throated Pipit by Ben Porter
This blog was kindly contributed by Ben Porter (@BardseyBen), www.benporterwildlife.co.uk.




Friday, 21 April 2017

Here come the Cuckoos!

The stop-start nature of this spring's migration has continued over the past week but breaks in the weather fronts allowed through a nice flurry of Ring Ouzels with over 60 records yesterday alone. Over the past week Ring Ouzels have been reported from the Isle of Wight to Edinburgh with 17 at Burnham Overy in Norfolk on the 20th April and 27 in the Cot Valley in Cornwall on the 18th April. Wheatears also arrived in good numbers and the graph below from BirdTrack shows that after a lag earlier on, the percentage of BirdTrack users seeing Wheatear has now caught up with the average for this time of year.

Graph showing percentage of BirdTrack complete lists featuring Wheatear
Graph showing percentage of BirdTrack complete lists featuring Wheatear

This is the best time of year to look out for Red-rumped Swallow and right on cue there have been half a dozen or so sightings over the past week. If you're visiting any coastal locations or freshwater marshes over the coming week look out for Swallows with very pale (sometimes reddish) rumps!


Red-rumped Swallow by Richard Crossley (The Crossley ID Guide Britain and Ireland) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

With high pressure dominating through well into next week we can expect a good arrival of migrants. We should see Pied Flycatcher, Whimbrel, Yellow Wagtail, Hobby and Arctic Tern all arriving in good numbers and more of our Turtle Doves returning too. We are receiving more reports now of House Martins returning to their nest sites, if you have any breeding near you then we need your help with our House Martin nest survey.

Three of our satellite-tagged Cuckoos are back in Europe now with one already back at his breeding grounds in the UK. Over the next two to three weeks we'll be heading rapidly towards the peak for Cuckoo records so if you want to hear a Cuckoo this year, this is the time to get out and listen. If you're very lucky you may even encounter an early Bee-eaterSquacco Heron or Purple Heron and it is worth looking out for rarer waders like Pectoral Sandpiper and Marsh Sandpiper stopping off on passage.

Cuckoo by Robin Lee
Cuckoo by Robin Lee

Over the course of the weekend, a cold weather front moving from north to south through Britain could produce a decent 'fall' of grounded migrants. Saturday morning looks like your best bet to head to a coastal watch point to witness this phenomenon for yourself, especially if there is a little rain early on . There is the potential for much colder weather early next week, with snow over much of Scotland and down to central England. How will our recently arrived migrants (and early breeders) cope with this cold snap? 

Thursday, 13 April 2017

Still waiting

The stop, start nature of this spring migration continues. The quiet spells in the weather provide windows of opportunity for migrants heading north through France and Spain, only for them to be closed by the next front to move through. This Friday and Saturday are a good example.

During the night of Thursday into Friday the conditions in France and across the Channel look good for birds wanting to make a move (see chart below). 





However, fast-forward to the same period on Friday going into Saturday and a front in the channel will have a blocking effect on birds heading north over the channel. 





Of course it will depend on the actual timing of the front moving through. If it is a little late, birds could set off across the channel and be grounded on the south coast as they encounter the front. If it moves earlier than forecast birds might be grounded in northern France, unable to move until the front has passed.

So, what does this mean for the weekend?

As the spring progresses more and more birds will take advantage of any window in the weather. We should see pulses of arrivals that by now should include Swallows in particular as they do still seem thin on the ground. Yellow Wagtail, Tree Pipit and Redstart should also be a feature, along with Ring Ouzel, Cuckoo and House Martin.

A few Garden Warbler should join the Blackcaps, although it feels like there are still a lot of Blackcap to arrive too. Reed Warblers should also take advantage of quiet overnight weather and make it back to their reedbed territories.

Where are all the Wheatears? It is a little worrying that Wheatear is trailing well behind its historic average in BirdTrack. The purple arrow on the graph is where it should be, whilst the blue dots are where we are this spring. Hopefully, they are just held-up and will flood in as soon as conditions allow, but you have to wonder what sort of winter they have had.


 BirdTrack reporting rate for Wheatear


On the rarity front, the warm southerly airflow we saw last weekend did bring a few overshoots with it in the shape of two or three Purple Herons, a Little Bittern, a couple of Western Subalpine Warblers, a Night Heron, a couple of Red-rumped Swallows and Woodchat Shrikes, two or three Black Kites and at least one Hoopoe. However, pride of place must go to the splendid male Rock Thrush that was found on St Martins, Isles of Scilly.
Rock Thrush courtesy of http://www.mpgoodeyphotography.com/apps/photos/

Friday, 7 April 2017

The floodgates are about to open!

During the last few weeks migration has been somewhat stuttering. Breaks between weather fronts crossing Europe allowed birds to move only for them to be stopped by the next batch of fronts to move through. That might be about to change this weekend as high-pressure moves over the UK. The winds will turn southerly, and at least for a short while will come from as far south as North Africa. This should open the floodgates for birds such as Swallow, Blackcap and Willow Warblers, birds that should be fairly widespread at this time of the season but are still a little thin on the ground.

Hobby by Jason Thorpe
Hobby by Jason Thorpe
We are still a week or so away from the peak migration period but we should see lots of birds arriving in the next few days.  Hobby, Grasshopper Warbler, House Martin, and Sedge Warbler  could arrive in force, along with the first flood of Whitethroat and, as the winds turn more south-easterly around mid-week, a few Lesser Whitethroat too.

Redstart should be seen more widely, and Pied Flycatchers are worth looking out for too.  In fact with the conditions looking so good, most of our summer migrants should be represented over the next few days, perhaps with the exception of those that have a late spring arrival time, such as Swift, Spotted Flycatcher and Quail.

Cuckoo by Charles Tyler
Cuckoo by Charles Tyler
Six out of our seven satellite tagged Cuckoos are still south of the Sahara in West Africa but we do have one that has crossed the desert. Hampshire Cuckoo "Selborne", has been in northern Spain for around a week and will probably make the final leg of his journey home in the next week. Although none of our tagged Cuckoos have made it as far north as the UK, Cuckoo is definitely worth listening out for in the next few days and keep an eye on the Cuckoo tracking maps for daily updates on the position of our tagged birds. 

At sea, Common Terns on the move could be joined by the first Arctic Terns of the spring, and when terns are on the move skuas move too, so there ought to be a few Arctic and Great Skuas seen.

Arctic Skua by Moss Taylor
Arctic Skua by Moss Taylor
Conditions look to be perfect from the early hours of Friday morning right through to at least the early part of next week, and whilst the south coast ought to be the place to be, we could all enjoy spring arrivals during this time.

Black Kite by Jill Pakenham
Black Kite by Jill Pakenham

With the warm winds coming from so far south, overshooting spring migrants should also be a feature. Along with the possibility of a few more of the birds we have seen during the last week, Red-rumped Swallow, Black-winged Stilt and Woodchat Shrike. With the forecast weather it looks like we could be in for an arrival of southern herons, Purple Heron, Little Bittern and Night Heron are all on the cards. We could also see the odd Black Kite and maybe Sardinian Warbler.

The conditions are also good for departing migrants and it is worth keeping an eye out for the last Redwings and Fieldfares, and at sea, Brent Geese.

Friday, 31 March 2017

Migration still slow

Whilst at times the weather here has seemed near perfect for the arrival of summer migrants, weather fronts further south in France have blocked their progress and the opening of the floodgates hasn’t quite happened.

This might all change on Sunday. High-pressure is forecast to extend from northern Britain all the way to the south of France and, if fog holds off, we could see the first big wave of summer migrants arriving. It will also help birds waiting to leave get on their way too, such as the Greylag Geese and Redwings on the northern isles.

Black Redstart by Ron Marshall

This week has been slow but there has been some visible migration. Meadow Pipits have pretty much been leading the way, with numbers in the low-hundreds being counted at some coastal watchpoints. Chiffchaff and Sand Martin have reached low double figures and Ring Ouzel has been seen a little more widely. Black Redstart seems to have been the most obvious of the grounded migrants, with small numbers being seen at many sites across the country.

Small numbers of Willow Warbler have pushed north, the first Common Terns have arrived and a few Sedge Warblers have made it back to a few reedbeds. Scoter, both Common and Velvet have been on the move at sea and there has been a small movement of Great and Arctic Skuas.

Black-winged Stilt by Moss Taylor

The first of our satellite-tagged Cuckoos has made it back to Europe and is currently on the southern edge of the Pyrenees, whilst the remainder are still in West Africa preparing for their own desert crossings. 


On the rarity front, Alpine Swift, Red-rumped Swallow, Hoopoe and Black-winged Stilt all arrived this week, and with high-pressure and light winds forecast for the early part of next week, we could be in for more of the same, and maybe Woodchat Shrike or Rustic Bunting.

Friday, 24 March 2017

Spring migration held up

The series of weather fronts crossing the UK and France during the last week had the predicted effect, putting the brakes on migrants arriving from the south. However, there were odd gaps in the weather that did allow some birds to move. Chiffchaffs and Wheatears reached double figures and more Sandwich Terns are being seen at many south coast sites; the first Common Whitethroat and Sedge Warbler got through too.
Singing Sedge Warbler by Peter Garrity

A few BTO members of staff have been hearing Coot flying over at night, along with Redwings and Fieldfares and it reminded me that the overwintering Coot on the Isles of Scilly left the islands during March. The ringing recovery map below shows just where some of them might have been going, amazing for a bird that looks so ungainly in flight during the day!

Map showing ringing recoveries of Coot: Colour of location: Ringed in Britain & Ireland, found HereRinged here, found in Britain & Ireland
Winter geese numbers are beginning to fall quite rapidly but there are still decent sized flocks at some east coast sites, 700 Brent Geese are still on the Humber. These will almost certainly take advantage of the improving weather during the early part of next week and move off.


The forecast for the next week is for high-pressure building from Saturday/Sunday and at present Sunday looks good for both birds leaving and birds arriving. We could see the first big arrival of Chiffchaffs. Moving into Monday, the wind is forecast to turn southerly and come from as far south as the Pyrenees and the temperature is due to increase too - ideal conditions for any migrant birds that have been held up in France during the last week, and for those birds waiting to head off north and east. Many of us might see our first Swallow of the spring, always a good bird in March and the first real flush of Ring Ouzels

Ring Ouzel by Carl Day
On the rarity front, at this time of the year Alpine Swift and Hoopoe are always favourite but Great Spotted Cuckoo can also be a good bet this early in the season.

Friday, 17 March 2017

Spring has almost sprung!

The southerly airflow during the latter half of the week produced the first noticeable flush of migrants, the most obvious being the number of Garganey that made landfall and quickly moved north. The largest group was a party of 10 that were seen on 11 March at Grove Ferry, Kent. These were joined by Sand Martins, a few Swallows, House Martins and Little Ringed Plovers.

Little Ringed Plover by Marc Albiac
Mid-week saw a huge overnight thrush movement in the eastern half of the country with lots of observers reporting Redwings and Fieldfares heard going over during the hours of darkness. Interestingly, among these were reports of Wigeon doing the same.

The first southern overshoots arrived in the form of Alpine Swifts in Co Cork and Kent, and the first Hoopoes in Co Kerry and Dorset. Pride of place has to go to the Baillon’s Crake that was seen coming in off the sea in Cornwall and spending a short  time walking around rocks on the beach at St Levan before heading off west, never to be seen again.  This is a migrant with less than 100 records in the last 100 years!

Hoopoe by Richard Nuernberger
Several early birds were also seen that included a few Willow Warblers, the first Redstarts and Yellow Wagtail, a few Ring Ouzel and the first Cuckoo (in West Sussex). Our seven satellite-tagged Cuckoos are all still south of the Sahara.

Cuckoo by Edmund Fellowes
The forecast for the next three or four days isn’t very conducive for much migration. Wet and windy weather from the north-west will seemingly dominate but there will be moments of quieter weather in between the weather fronts when birds ought to move.

So, what might we expect? The weekend isn’t looking great but early next week we should see some migration. Wheatears are tough little birds and will take any opportunity and we could see them arriving in better numbers than has been the case so far, along with more Sand Martins and Swallows, and the first real movement of Sandwich Terns. There has been a small migration of Painted Lady butterflies too and we can look forward to seeing more of these over the next week or so.
Painted Lady by John Harding


Monday, 13 March 2017

Redwings at night!

Last night saw a major movement of Redwing in eastern England. Several hundred birds were counted in under an hour from 10pm onwards in Thetford, Norfolk. With few reports from anywhere west of Cambridge, it looks like a band of cloud with some very light drizzle may have concentrated birds that were already on the move.

BirdTrack reporting rate for Redwing
Observers also noted small groups of Fieldfare, Snipe and Song Thrush, as well as less expected species in the form of Teal, Wigeon and even Coot passing overhead in the dark. With similar conditions forecast for this evening and the rest of this week, it is well worth having a listen after sunset for Redwing on the move.

Redwing by John Harding
If you are not familiar with the flight calls of Redwing, here is a good example:

http://www.xeno-canto.org/243650

Fieldfare call: http://www.xeno-canto.org/350645

Later this week could see another movement of migrants, with southerly winds on Wednesday likely to help birds move across the Channel. Some more unusual arrivals could well put in an appearance, perhaps more Alpine Swifts after last weeks sightings?

Friday, 10 March 2017

Migration stutters a bit

The pulse of weather fronts that we have experienced during the last week have had a stop-start effect on arrivals and departures. In between the days of wind and rain there have been a few fairly settled days with light winds. During these more Sand Martins have arrived, along with the first Ospreys, Garganey and Willow warbler of the season.
Osprey by Sarah Kelman
Those leaving have also taken advantage of the calm between the storms. Pochard, Goldeneye and Common Scoters have been on the move, as have Brent Geese and Red-throated Divers; 335 of the latter were counted flying past Spurn, East Yorks on the 4th. Whilst there are still Redwings and Fieldfares to be seen, the BirdTrack reporting rate graphs show the steady departure for both.
BirdTrack reporting rate for Fieldfare
It looks like we are heading into another week of unsettled conditions but there will be odd days when there will be a window of opportunity for birds to move. Saturday looks like one of these. The front that has been blocking migrants in northern France for the last couple of days should have moved further east and the relatively light winds and settled conditions on Saturday should see held-up migrants move north.
Wheatear by Amy Lewis
We might see the first real arrival of Chiffchaffs and Wheatears, along with a few Blackcaps and more Sand Martins, Little Ringed Plovers and Garganey. The weather further north in the UK, and across the North Sea, is forecast to be a little more unsettled, so we might hang on to some of our winter visitors for a little longer. 

Now is the perfect time to brush up on your warbler identification skills so don't forget that we have video tutorials to help you separate Willow Warbler from Chiffchaff and Blackcap from Garden Warbler. If it's Swallow, Swift, House Martin and Sand Martin which cause you more of an ID headache then take a look at our Hirundines and Swift ID video

Friday, 3 March 2017

Spring migration gets underway

It has been a week of arrivals and departures. Parties of Bewick's Swans have been reported heading east, continuing on to continental Europe. Pink-footed and Brent Geese have been heading north too, as have Redwing and Fieldfare.


Reporting rate of Fieldfare on BirdTrack

 A short spell of southerly winds in the last day or two seems to have encouraged the first arrivals of hirundines, with three House Martins, a handful of Sand Martins and a Swallow reported.

The weather patterns look very unsettled for the week ahead, with the wind switching between southerly and westerly. More hirundines could start arriving if the wind remains southerly, as well as potentially the first Wheatears.

Wheatear by Paul Hillion/BTO

These could be joined by the first Chiffchaff from wintering sites around the Mediterranean basin joining our wintering birds. The historical reporting rate of Chiffchaff on BirdTrack shows a noticeable increase in early to mid March.

Reporting rate of Chiffchaff on BirdTrack

Paul Stancliffe and Stephen McAvoy

Friday, 13 January 2017

Cold-weather movement

With most birds settled in their chosen mid-winter sites, it can take unusual weather conditions to make them move. During the next few days, strong winds and freezing temperatures, as well as local heavy snowfall could well start to force birds from these areas.

Birds who are dependant on clear ground to feed, such as Lapwings, Golden Plover and Skylark will move to find areas clear of snow and frost. At times these cold-weather movements can be spectacular and can be witnessed anywhere in the country, not just along our coasts.

Lapwing by Jeff Baker/BTO


As smaller waterbodies freeze, wildfowl will be forced to search for new and as yet unfrozen sites. It will be well worth checking any local gravel pits or lakes for new arrivals - Goldeneye, Tufted Duck and Pochard may well be on the move, along with surface feeders such as Teal and Wigeon.

Drake Goldeneye by Jill Pakenham/BTO


Geese, being grazers, also struggle during prolonged snowfall, and Bean and White-fronted Geese have been on the move during the last couple of days. Further geese (amongst other species) may also arrive from central Europe as snowfall covers previously clear areas, in what has been a relatively mild winter so far.

Iceland Gull by Michael Bell (via BirdTrack Flickrpool)
 
Iceland and Glaucous Gulls have been increasingly noted along coastal areas in the north and east of Britain and Ireland, including up to 37 on Shetland alone. Strong northerly winds over Friday may push birds further south and even to inland areas. Indeed, single Iceland and Glaucous Gulls have even reached the BTO Offices in recent days. Any large congregations of large gulls will be well worthwhile checking for 'white-wingers' over the weekend.

Reporting rate for Glaucous Gull on BirdTrack

 
Ivory Gull by Chiddy Mark (via BirdTrack Flickrpool)

At coastal sites, there is an outside chance of even rarer gulls, such as Ross's or Ivory. One of the latter has already graced the North Sea coast of Germany this month so could well put in an appearance anywhere along the east coast of Britain.

Paul Stancliffe & Stephen McAvoy