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, 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?