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, 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:

Fieldfare call:

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