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Sunset in Nenetskiy reserve

Why do birds migrate?

The simple explanation is because then can. Being highly mobile and fast, birds can fly anywhere if they have enough energy, and it is energy, or rather food which makes birds migrate.

Many areas of the world alternate between productive and barren, and birds, with their lightweight hollow bones, super-efficient respiratory system, heat saving design and excellent (if poorly understood by humans) navigation abilities, are perfectly placed to take advantage of such seasonal changes. Bewick's swans for example, fly to the Arctic tundra to exploit the brief, abundant summer, before leaving when winter arrives. They breed whilst there is twenty four hour daylight and large amounts of food to fatten them up before the flight home.

There are other factors that may also encourage birds to migrate. Areas that seem to have plenty of food all year may have a high amount of predators, parasites, or even competing bird species that make it more advantageous for some birds to leave to breed elsewhere.

How did migration evolve?

The key to the evolution of migration seems to be the genetic trait found in birds, insects, and crustaceans to name but a few. All of the above groups have a behavioral tendency for partial migration, and studies on the black cap and redstart species have shown that all of the main prerequisites for migration, and non-migration are under genetic control (Berthold 2001). These include fat storage, timings, length of migration and so on.

Experiments with partially migrant blackcaps have also shown that complete migratory, or complete sedentary populations can be produced within 4-6 generations, (Berthold 1999) showing that partial migration is a trait that allows bird populations to migrate or stay put depending on which is beneficial. Whichever group is most successful over time will raise the most young, and the population will become mostly migratory, or mostly sedentary but with the opportunity to change if environmental conditions change.

barn swallow Today in Europe, the evolution of migration is still changing thanks to the end of the ice age 15000 years ago. The ice age reduced bird populations which today, are still dispersing into areas where they once lived, and so evolving new migratory routes.

In the future elements such as climate change may produce more sedentary populations as birds no longer need to head south for the winter, so the number of migratory journeys, or the length of each journey could change as newer, more local wintering places are found. However, considering some birds, such as swallows, fly to Southern Africa when they could easily, it seems, winter in southern Europe or North Africa, shows that historic routes, that are genetically transferred, are hard to change.

For more information about bird behaviour visit
BBCi Nature


Talking Point:

Helen - BBC NHU Bristol
Hi Mondo Yes indeed there are spotters looking out for the birds. Unfortunatley, now that the transmitters are down, that is the only way to spot them. Their leg rigs are large though, so fingers crossed someone will see them.

mondo, halifax
for all we know kostya could already be in england, are you relying on a spot to varify this or is he being tracked in other ways?

Gerry Ireland
We are following every report and moving small cut-out swans around on a large wall map of northern europe. Crildren have not only learned about nature but geography as well. Fantastic project bbc keep up the good work you have lots of listeners here in ireland

Helen - BBC NHU Bristol
Hi Steve in Halifax. As far as we know Huck's not in a pie! He is moving around - just not going very far. In fact, he seems quite happy in Finland, despite it not being a traditional place for Whoopers to stay over the winter. We'll just have to wait and see if he moves when it gets colder, and heads for Southern Sweden or the UK, as we would expect.

John Phelan, York
What happened to Pechora?

seve, halifax
what has happened to huck? is he in danger of being in a pie because he hasnt moved for weeks?

So he is back with us good old kostya i thought you had got it wrong surley eagles and foxes dont eat transmitters just one thing with his tag do we no where he should finish up

James, Ferrybridge
Great news about Kostya. Let's hope the other lost swans have similarly only lost their transmitters.

Helen - BBC NHU Bristol
Hi Helen in Peterborough. The latest news is that 12J Kostya is alive and in Holland with no transmitter. The two Bewick's swans 11D (Andrei) and 12D (Anatoli) both lost their signals. This is most likely to be satellite or battery failure. We have plenty of birdwatchers out looking for their rings, so we may be able to find out where they are. Finally Huck is stationed in Finland, but we fully expect him to move soon, as whooper swans are not known to stay in Finland over the winter. That's it for now - updates can be found via the "Eyes along the Route" section or via the headlines.

Helen in Peterborough
Where are they now? You seem not have followed the story through to the end. Please update!

Bobbie D- Australia
migration is a cool thing!

Helen - BBC NHU Bristol
Hi James from Ferrybridge. It seems it was an Argos satellite error and Andrei is still in Denmark. These things do happen unfortunately. There are activity monitors on the satellites which show if the swans are flying. Hope they fly soon!

James, Ferrybridge
Is it likely that Andrei is sitting on an oil rig or in the lee of one? Presumably there's some history or otherwise for such behaviour. Colin says that he's not flying - is this know because of two passes of Argos giving the same location or is there some bimetric data available from the swans?

Eddie Brennan, Perth
What a truly awe inspiring production. Nature really has weaved a miraculous tapestry. So long as some of mankind can appreciate this wonder and learn from it, then there's hope for our species too. Thank you for several hours of entirely enthralling radio.

Helen - BBC NHU Bristol
Hello! In answer to Richard in West Wales, we only put transmitters on 6 swans because that's all we could afford. The transmitters are very expensive indeed! Finally we haven't stopped broadcasting the swans' locations, as the site is being updated as and when the swans are flying. At the moment they are resting. For the most up-to-date location listen to the Today programme tomorrow morning who are broadcasting an update due to popular demand!

Tim Reynolds, Witchford, Ely
Living not far from Welney I have always taken an interest in the swan migration and visited this wetland. Your project in following the migration 'live' is fascinating to follow. Thank you so much and keep up the good work.

Muppets at Bearsden Academy
We think its a bit 'sad' following these swans but we're doing it anyway!

Brin: Harrow, London.
I never seen such a project like this before. Itz just amazing think only BBC can do. Tracking swans on is a part of my daily schedule now. Well done to all. Good luck.


bob heathrow
simply perfect.what a wonderful documentary

Richard, West Wales
The whole swan migration project was gripping and the programme during which the swans were caught, tranmittered (?) and released was entrancing. Two questions - why did you put transmitters on only six, and why did you stop broadcasting the swans' location? Anyway, thank you.

Terry in Edinburgh
The swans are part of my life now!

Jennifer, Toronto, Canada
My sister in Northumberland has just told me about this site. She is avidly following the flight of the swans. This is the first time I have heard of such a project. Good luck to you and all the swans!

Ken Prichard Jones, Warnham West Sussex
Fortuitously on Saturday morning two swans flew onto one of our lakes here. We had a serious oil pollution problem from upstream last year and our cob died as a result. His mate and cygnets survived and left in early summer. We think one has returned with a mate which is ringed with an orange band marked "70". Is there any way of checking where this Swan was ringed?

Carole: London
Please repeat the project each year.Having seen the wonderful film, Winged Migration, and recently visited a swannery in Dorset, I have enormouse respect for these amazing creatures. What a refreshing departure from the rest of the rubbish we are subjected to by the media...more please!

David and Emma, Stockholm
We, and family in multiple locations, have been following the project for weeks. Excellent coverage, + v interesting to hear on web radio. Thank you. We've been pleased to see small number of Whoopers and 1 Bewick flying over our house outside Stockholm. Great to know a little more about their vicissitudes. Are you planning on tracking the spring migration of the swans? Any chance you may follow other species next year?

Roberta Spencer, Chichester, England
Now that the broadcasts covering the migration of 'our' 6 swans has come to its delightful end please let us know the outcome of each of them if possible.

Peter Allen, Sunderland
You should try to link this with TV as well as radio. Thirty seconds or so on the end of a news report would increase awarness no end.

Wonderful programme on both radio and the web. I am one of the few who does not have TV and now many more will see the benefit of radio and how it brings people together in a common bond. Thank you for all your information and a wonderful project Helen.

Tim in California
Brilliant...listened to the progamme driving from Winchester to Chichester last week and now listening to the "landing" on a wet night in San Francisco..Thanks.

Thank you BBC and WWT: this is a wonderful project. Please continue until we have received all possible information about 'our' swans!

paul w. cambridge
i have just started to look at the tracking of these whooper and bewick's, and it is very interesting that this is being done, keep up the good work and i will keep looking at the updates, maybe we could see more pics of the washes they will land on. keep up the good work!!!

Steve Hughes - Reading, Berks
After being amazed by bird migration for many years, how wonderful it is to be able to track these swans step by step in this way. May I appeal to everyone to join the WWT and so enable them to carry on the fantastic work they do.

Helen - BBC NHU Bristol
As far as the solar flare question from Jeremy Gaskell, London, goes, it could well be that they have interfered with some of the satellite transmissions, although we are not sure how - but they are not designed to withstand such electrical charges around them! The results would be intermittent however, and may not account for our "losses". It is possible, especially in the case of Anatoli, that his transmitter has just failed, and that our Dutch bird watchers will spot him, as, judging by the route he was taking (see WWT's map) he was headed that way. Our watchers on the ground in Estonia are saying many of the swans have moved on, so Holland is the most likely place for them now.

Catherine - London
This is a fantastic project. I have learned so much. If only your colleagues in television would treat the audience with the same respect you do, ie assume we are intelligent and can follow a story for more than three minutes. Please can this project continue after this week or at least give us updates. Thank you so much.

fantastic and informative. a valuable project, im glad my license money is being used to compile such useful data as well as entertaining me. more of the ssame please!

An interesting and educational project. We are following the birds, courtesy BBC.Thanks

Dave the dentist - Isle of Skye
I always think that Winter starts with the arrival of the whoopers on the Island. This morning as I walked the dogs, I saw the first two whoopers feeding on the lochan behind the house. Because of the wonderful coverage by Radio 4, I was almost moved to tears, as I can now fully appreciate the enormous distances negotiated by these beautiful birds. A tremendous piece of reporting. Don't stop at the end of the week - let us find out what happens to Huck; I want to know if he finally ends up here on the island along with our population of wintering whoopers! Thank you Beeb!!

Jeremy Gaskell, London
Please could you explain to us non-scientists the impact that the solar emissions is having on the monitoring process and quite what these emissions are and how frequently they occur. I wonder how far their impact goes to towards explaining the 'negative news' from 4 out of the 6 birds.

Helen - BBC NHU Bristol
In answer to Fred from Wolverhampton, it appears the swans have stopped because they have! Our two remaining swans Bewick's 11D (Andrei) and Whooper Huck (HUC) are both resting and feeding on lakes along their route. The weather is good so they are unlikely to move soon. The others unfortunately, have stopped for other reasons, either the transmitters have fallen off, or they've met untimely ends. See the "Eyes along the Route" section for all of the history of their migrations.

fred wolverhampton uk
why does it appear that the swans have stopped? 15.30 thursday 6th

Helen - BBC NHU Bristol
In answer to Miriam Colin writes: The transmitters keep going until the battery runs out, which should be mid-December. We can tell if the transmittter stops moving about, but we usually do not know whether it fell off, or the swan met with an accident. There was a Brent Goose that migrated across Greenland and stopped, and was eventually located in somebody's larder, with the transmitter still beeping away. We have our suspicions about one of our missing swans.

Helen - BBC NHU Bristol
In answer to Lynne, Colin Pennyquick says: "Flying non-stop at its normal cruising speed, a swan could cover about 1500 km in 24 hours, i.e. about the distance from the Pechora mouth to where they are now, at the eastern end of the Baltic. However, we seldom see them fly more than 500 km in one go, and they land for short rests quite often. They do fly at night in clear weather, but they usually land if caught in mist or fog, by day or night"

Helen - BBC NHU Bristol
In answer to Daphne Shackleton , Eileen Rees from WWT said: The vast majority of the whooper swans wintering in Britain and Ireland come from the Icelandic-breeding population. The birds therefore have a relatively short flight (c. 800 km) from the breeding grounds to their wintering sites, and can arrive promptly in autumn. Our earlier satellite-tracking of Whooper Swans between Britain and Iceland found that they can make this journey in as little as 12-13 hours, although one bird blown off course in spring spent 4-5 days at sea!

Phil Royle
There are times when I wonder about the BBC licence fee, but this project alone is worth the money if most of the television dross is not

Lyn :uk
the maps show the route of the migration very clearly. Please could you tell us how much distance a swan ( say, Andrei) covers in a day's flight? ( and do they fly at night?) thank you.

Gerry Hoey Ireland
I listned to your progrmme last night ''spellbound'' it was so well produced I felt I was on that boat.Well done to the team. Is there any chance of any of these swans coming to the East coast of Ireland.

Elizabeth Craig, Queensland, Australia
As my sister in Chichester England comments, we do indeed take a great interest in this project. What a great deal of pleasure the bird world as a whole provides us with. Thank you for a more intimate window into that world.

miriam, Norwich
how/ do the transmitters stop working if the bird dies?

Robert Francis - Poole
No wonder they are going in a straight line, this year they have a GPS on their back!

Helen - BBC NHU Bristol
In answer to Dave in Lancashire's question, Colin Pennycuick replied: Hi Dave - It's a good question, but difficult to answer! Unlike a marathon runner, a bird cannot slow down if it gets tired, because flying slowly is harder work than flying at the "minimum power speed", which is about 18-20 metres/sec for a swan. Its options are to keep going at that speed, or stop. Actually all of our swans started by making short hops, and we think they went down quite often for short rests, even after they got going. There are other (smaller) birds that fly much longer distances without stopping. For example the evidence is fairly convincing that Alaskan Bar-tailed Godwits fly direct from Alaska to the northern tip of New Zealand. That is over 10,000 km, and takes them over a week, with no rest, no food, and no sleep.

Helen - BBC NHU Bristol
In answer to Margaret in Huddersfield, we deliberately chose male swans to be tagged because they are stronger and heavier than female birds, and so more likely to survive the journey.

Helen - BBC NHU Bristol
In answer to Andrew in Derby - it certainly would be worth visiting Slimbridge at the moment, as there are swans arriving all the time. They haven't had their first "swan fall" yet as the mild weather is delaying things but numbers are building slowly. We doubt if our swans will be back by the weekend. Visit the WWT site and on there you will find details of how to get to the reserves, and the opening times/cost.

Margaret - huddersfield
is it just chance that all your swans are males or do the sexes migrate differently?

Andrew Bennett, Derby
Do Bewick's swans, Hooper swans and Mute swans inter-relate or simply ignore each other? One of those being monitored is referred to as 11d: I sincerely hope nobody will refer to him as "One penny short of a shilling." Would it be worth visiting Slimbridge during this exciting time, or is it all confined to the East Coast?

bbcfan berks
The team photo was brilliant - they looked just like me and my nearest and dearest - unlike all those pretty puppets on the TV

Dr Dakers, Wokingham
What a wonderful project - I have discussed this with several classes who have been fascinated to see Science in action, not just in the classroom.

Helen - BBC NHU Bristol
I had a word with Eileen Rees from WWT who said about the swans Holly saw in Norway: "The swans in Norway in December and January are almost certainly Whooper Swans; Bewick's Swans occur there only as vagrants. Whoopers breed across central and northern Scandinavia, particularly in Sweden and Finland, but migrate to Denmark, southern Norway, southern Sweden, northern Germany and the Netherlands for the winter months. It's quite possible that the Whoopers will stay in Norway all winter, but they may shift south if their feeding and roost sites freeze over. We now know that Russian-breeding birds such as "Huck" also winter in these areas, although we're not yet sure where "Huck" will end up in mid winter. Probably not as far west as Norway!

Dave Field - Lancashire
If we want to run a marathon, we need to train for weeks. How is it that migratory birds seem to be able to leave directly from their normal lives and fly phenomenal distances without any particular preparation, other than fattening up?

Helen - BBC NHU Bristol
In answer to some of the questions, it isn't thought that the satellite transmitters hinder the swans as they weigh very little in comparison to the birds. They are designed to fall off once the journey is complete and yes they can fall off prematurely, which is what we think may have happened to Alexei's transmitter. Alexei was also ringed (as were over a hundred swans on the trip to Russia) so hopefully we will find him again when he arrives at his winter home. Finally yes the solar sunspot activity has affected the satellites and we lost touch with all 3 birds for a day and a half! A bit worrying as you can imagine. We're trying to find out if it affects how the birds' navigate.

Holly Anderson, Cambridge UK
Visit Welney each Winter with my mother and its great to find out what a journey the swans have made. I have a question: I have seen "song swans" on rivers near Oslo in the Winter months (Dec/ Jan) are these Whooper or Bewicks? Do they stay in Norway or move South later on? Is there a pattern for birds coming from different areas?

Valerie Gale/Vancouver
Hi Brett. Very interesting to hear about the Bewick Swans in the Arctic. Looking forward to learning more about the migration.

ray,on. canada
what a wonderfull project, keep up the fantastic work.

Stan Bueler Sherborne Dorset
What a really wonderful project. My wife and i are both oldies and more or less house bound but will be following the progress of the swans with great interest

CHRIS aberdeen
I check my pc every morning to see latest positions. We rarely see Bewick`s up here, but plenty of Whoopers. I find this project very exciting and informative and hope it can be continued each year.

John Chambers Fareham
I've fly radio controled gliders. I've noticed how migratory birds fly at a hight that is not too high that the air is too thin to be hard work and not too low to have to climb and dive to aviod buildings and trees. They always have a perfect cruising altitude. I remember years ago flying an early electric powered model, it just would not go above fifty feet cos of the air thiness. Great website and project! I will listen to Radio 4 more! I would like to suggest (not critisise) that the journey that these birds make is a very delicate balance, unless the transmitter is very light it could mean the diference of wether the bird makes it or not and thus afect your results. What percentage of the birds wieght is the transmitter?

David - Blyth, Northumberland
I think I've found this a few days too late, but wow, what a great Project and well done BBC - it is this kind of stuff that makes the licence fee so worthwhile.

Helen - BBC NHU Bristol
In response to people who have been wondering why some of the birds haven't flown yet, it seems like there has been a problem. Please visit "Eyes Along The Route" section. Thanks!

Helen - BBC NHU Bristol
We're not sure! But the fact is there are between 20 and 25 thousand Bewick's in the Western population of which up to nine thousand winter in Britain, so if all goes well, at least two should arrive in the UK!

Ann Popham, Ashtead
How can you be sure that the swans will come to the UK?

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