21.Mother and father goose lead the way…

You’ve probably seen geese flying in a tight V-formation, and you may have wondered why.

It seems that the upwash from the wings of the lead bird gives a bit of extra a lift to the birds following on either side, and thus reduces their energy consumption - an effect that continues down the line to the tails of the V. That really matters on a long migratory journey, but the lead bird obviously has to work a bit harder than the rest. So it came as no surprise when some recent studies showed that birds took turns in taking the lead, thus sharing the extra burden.

But something slightly different emerged from a fascinating new study.

Researchers attached lightweight GPS trackers and accelerometers to wild white-fronted geese belonging to four family groups setting out on their long migration from the Netherlands to northern Russia. This meant that they could not only see exactly where each bird was in the formation, but also how fast they were flapping their wings.

It turned out that only the parents ever took the lead. Usually the father, but sometimes the mother - depending on the wind conditions. The mothers had to flap their wings faster when they were out in front, but the fathers apparently did not need to.

It makes good sense for the parents to take on this leadership role, because it increases the chances of their offspring surviving the rigours of the long journey - and thus having a chance to pass on their genes to future generations (so-called ‘kin selection’).

But this system probably also helps the young, first-time migrants to learn the route they need to follow in future, where best to stop for refuelling, how best to avoid dangers - and indeed how to fly most efficiently.

In groups of homing pigeons, less experienced birds follow more experienced flock members, and this helps them to learn routes. Further experiments will be needed to see whether this is also true of young migratory geese.

19.Young cuckoos are even cleverer than we thought…

A couple of weeks ago I wrote about the amazing journeys undertaken by adult Mongolian cuckoos - like Onon in this picture.

Here I talk very briefly about a fascinating new study, just published in the journal Nature. It reveals that young cuckoos - making their very first migratory journey all the way from Russia to Southern Africa - can somehow tell when they have been moved 1800 km to the east of their proper route. And, just like experienced adult birds, they can change course to compensate for this displacement.

It’s the first time such an ability has been clearly demonstrated in young birds and it leaves us wondering how they solve a problem that we humans only cracked a few hundred years ago.

18.My interview for the Stratford Literary Festival

I was lucky to be interviewed by the novelist Clare Clark who asked extremely good questions. I hope my answers measured up to them!

17.Amazing cuckoos

There’s no better way of getting a sense of what migratory birds can do than to look at the maps that record their journeys.

The Mongolian Cuckoo Project has been using tracking devices to follow the amazing journeys of cuckoos returning home from Southern Africa in recent weeks. Do please visit their excellent website to see the achievements of Onon, Bayan and the other birds. It’s a real model of public engagement in science.

Quite apart from the extraordinary distances the birds have been covering, I’m struck by the close similarity between the routes they have been following. It would be fascinating to know exactly how they perform such impressive navigational feats.

Presumably, like many other migratory birds, cuckoos have a sun and star compass as well as a magnetic one. And when they have made their first migratory journey, it’s safe to assume that they use familiar landmarks to help them retrace their route. But of course there are no landmarks over the ocean!

And cuckoos face a special problem. Their unusual lifestyle means that when they first head south, they must do so alone - because their parents will have left before them.

So how on earth do they find their lonely way over thousands of miles of land and ocean to the areas in Africa where they pass the winter months? Some kind of genetic program must be involved. But how does that work? We just don’t know.

One last thing: why not lend your support to this brilliant project by following this link?

15.How do dogs find their way home?

Dogs seem to have a built-in magnetic compass…

12.The amazing journey of the blackpoll warbler...

Here is the first of what, if I have the energy, will be a series of short videos introducing some fascinating aspects of animal navigation. It relates to a tiny American bird: the blackpoll warbler.

These birds normally only weigh about 12 g and even when they fatten themselves up for their long migratory journey they only put on another 5 g. I think you’ll be as amazed as I was to discover what they can do.

The original research on which this story is based can be found here: DeLuca, W. V., Woodworth, B. K., Rimmer, C. C., Marra, P. P., Taylor, P. D., McFarland, K. P., ... & Norris, D. R. (2015). Transoceanic migration by a 12 g songbird. Biology letters, 11(4), 20141045.

11.Francis Chichester learns to navigate...

Sir Francis Chichester (1901-1972), best known today for his solo single-handed voyage around the world in the yacht Gipsy Moth IV, first learned to navigate in the air. In fact, he was a pioneering aviator (the first to fly solo across the Tasman Sea from east to west) and he only took to sailing towards the end of his career.

Chichester was to become an expert navigator, but, like the rest of us, he had to learn. Here’s his entertaining account of how, in 1929, he flew a Gipsy Moth aircraft from Liverpool to North Devon, not long after he had acquired his solo license (‘Bradshaw’, I should explain, was the standard railway handbook of the day):

The aeroplane was so knew that it had not yet been fitted with a compass. I was ‘flying by Bradshaw’, following the railway lines across the country, and I wondered if I could fly by the sun. The sky was overcast…I climbed up into the cloud, and proceeded until I had passed through a 9,000-feet layer of it to emerge at 10,000 feet in brilliant sunshine over a snowy-white field of cloud. Not only had I no compass, but no blind flying instruments at all…After flying along for half an hour by the sun, I climbed down through the 9,000-feet layer of cloud. I then wanted to find out how accurately I had carried out this manoeuvre, and I used a sound principle of navigation. I fixed my position by the easiest method available – I flew round a railway station low down, and read the name off the platform. By some extraordinary fluke I was right on course. I probably uttered for the first time the navigator’s famous cry ‘Spot on!’

From The Lonely Sea and Sky, Chapter 7. (Hodder and Stoughton, 1964)

10.Barry Lopez on polar bear navigation

In his classic work, Arctic Dreams, Barry Lopez occasionally refers to the remarkable navigational abilities displayed by animals of the far north. Polar bears for example:

“ Bears make use of mountain passes, ravines, and other features of the land in such a way as to suggest that these are traditional routes…

” Beyond using celestial clues and a knowledge of prevailing winds and currents, which reliably guide Eskimos across the angular topography of shifting sea ice, no one knows how bears find their way. But they consistently travel directly to aggregations of seals; they return to core denning and breeding areas every year; and they find their way unerringly to the coast from hundreds of miles offshore. This would be astonishing enough if they only did it on land, where there are perennial landmarks, but they also do it at sea, where a frozen landscape is created anew each year, which can change from one day to the next… In some areas of stable ice, bears may travel for weeks without seeing a break in the continuity of the sharp blue line of the horizon…” [from Chapter 3, Tôrnâssuk.]

Maybe, as Lopez suggests, the bears do indeed use celestial cues, like the azimuth of the sun. Maybe they also know about prevailing winds or currents. It’s equally possible that they use their acute sense of smell. Lopez also speculates that the bears make use of maps in their heads - or cognitive maps - but I’m not sure the evidence really supports such a claim. Perhaps they are just good at DR? In any case, the secrets of polar bear navigation are one more mystery to add to my growing personal list of puzzles!

9.‘Incredible Journeys’ is now out in paperback in the UK

It’s also available as an audiobook - read by the author!

8. a video introducing ‘Incredible Journeys’ (‘Supernavigators’ in North America)

This is a 15-minute version of a video I made recently as an introduction to some of the main themes of the book. I hope you enjoy it!

7.Celestial navigators - human and non-human

People have been using the sun, moon and stars to help them find their way for a very, very long time.  

And not just people but other animals too – like birds, moths and beetles – to name but a few.  This is a really exciting area of research and new discoveries keep piling in, many of which are described in Incredible Journeys.

Eric Warrant and Marie Dacke, for example, have shown that nocturnal dung beetles roll their carefully sculpted dung balls back to their nests using the light of the moon or the Milky Way as a guide.  

And recently Eric Warrant and David Dreyer have shown that the Australian Bogong moth also makes use of the Milky Way to maintain a steady course on its 1000 km migratory journeys (as well as a magnetic compass).

Bogong moth

We know that many birds that migrate by night orient themselves by paying attention to the rotational pattern of stars around Polaris, which marks the direction of true north.

My guess is that our prehistoric human ancestors would also have been pretty good at this kind of celestial navigation - tens of thousands of years ago.

What we know for sure is that the builders of Stonehenge and many other ancient monuments around the world are carefully aligned so as to highlight key celestial events like the summer and winter solstices – that mark the longest and shortest days of the year.  

And the amazing Nebra Sky Disc – discovered in Germany in 1999 – suggests that our Bronze Age forebears understood the very complicated relationship between the solar and lunar years.  It was made about 3,500 years ago. http://www.bibliotecapleyades.net/arqueologia/nebra_disk.htm

And the Greeks knew a thing or two.  The amazing Antikythera Mechanism – discovered by sponge divers over a hundred years ago – dates from around the end of the 2nd century B.C.  It’s by far the most sophisticated mechanical device yet discovered from the ancient world. The Antikythera Mechanism seems to be a complex mechanical “computer” which tracks the cycles of the Solar System: https://en.wikipedia.org/wiki/Antikythera_mechanism

We know frustratingly little about how the Greeks and Romans navigated at sea, though they travelled widely - and not just in the Mediterranean.  It’s always assumed that they didn’t use any specialised equipment.  But the Antikythera mechanism makes you wonder…if they knew that much about the behaviour of the heavens, would they not have put their expertise to navigational use?

On the other side of the world the islanders of the Pacific were already starting to venture out across the Pacific at least two thousand years ago. In their ocean-going sailing canoes they could make accurate landfalls on small islands after travelling as much as two thousand nautical miles across the open ocean.  

They didn’t use any instruments or even charts.  They relied only on their wits and finely-tuned senses – and a lengthy apprenticeship that started when they were children.  When western sailors like Bougainville and Cook first encountered these navigational prodigies in the mid-18th century they were astonished.  

Luckily we know a lot about how the Pacific Islanders navigated because, back in the 1960s, researchers started asking the right questions - before their extraordinary skills had completely died out.  

At the heart of traditional Micronesian and Polynesian navigation was an encyclopaedic knowledge of the sky.  The master navigators knew exactly where on the horizon 32 bright stars rose and set, and they could steer a steady course by reference to them.  They also understood that Polaris indicated where true north lay and during the day they could steer by the light of the sun by accurately allowing for the its gradual movement across the sky. They had many other remarkable skills and happily these are now being widely practised once more: http://hokulea.org

Before electronic aids like GPS arrived on the scene, navigators everywhere learned to observe the world around them very closely.  The colour of the water and its depth, the composition of the seafloor (tested with a lead-line), the behaviour of birds, the shape and colour of clouds – these and many other signs could give early warning of the presence of land, often long before it could be seen.

In former times, sailors everywhere paid the closest attention to the world around them - as well as the skies above them. Safe navigation depended on complete immersion in the natural world. It may not always have been as safe or reliable as navigating by GPS, but it was a far richer and much more rewarding experience. And it was also a great deal more robust: no problems like flat batteries, solar storms, spoofing or jamming!

6.The author of the ‘The Call of the Wild’ on celestial navigation…and the dangers of pride!

Jack London

https://www.falseart.com/jack-london-the-snark/

As readers of my first book, Sextant, will know, I’m not only interested in how non-human animals navigate. I’m a navigator myself and a devotee of celestial navigation - a skill seriously threatened by our increasing (and by now almost exclusive) reliance on electronic navigation aids, notably GPS.

So here’s an entertaining anecdote drawn from the author and adventurer Jack London’s account of his long trans-Pacific cruise in his yacht the Snark.

London and his friend, Roscoe, sailed from San Francisco in 1908 – heading first for Honolulu – without yet knowing how to use a sextant, which was a problem because they had no other way of determining their position!  So they simply taught themselves.

Roscoe was the first to try his hand:

‘…when we got out to sea and he began to practise the holy rite, while I looked on admiringly, a change, subtle and distinctive, marked his bearing.  When he shot the sun at noon, the glow of achievement wrapped him in lambent flame.  When he went below, figured out his observation, and then…announced our latitude and longitude, there was an authoritative ring in his voice that was new to all of us.  But that was not the worst of it.  He became filled with incommunicable information.

‘By an understandable and forgivable confusion of values, plus a loss of orientation, he felt weighted by responsibility, and experienced the possession of power that was like unto a god…The act of finding himself on the face of the waters became a rite, and he felt himself a superior being to the rest of us who knew not this rite and were dependent on him for being shepherded across the heaving and limitless waste, the briny highroad that connects the continents and whereon are no milestones. So, with the sextant he made obeisance to the sun-god…’

At first London deferred to Roscoe, but quite soon he rebelled.  Roscoe, he reflected, is a man like myself.  ‘What he has done, I can do.’  So he decided to learn for himself how to handle a sextant – a task that he found not too difficult.

‘The mystery was mystery no longer. …and yet, such was the miracle of it, I was conscious of new power in me, and I felt the thrill and tickle of pride… I was not as other men – most other men: I knew what they did not know, – the mystery of the heavens, that pointed out the way across the deep….No medicine man nor high priest was ever prouder…I was a worker of miracles. I forgot how easily I had taught myself from the printed page. I forgot that all the work (and a tremendous work, too) had been done by the masterminds before me, the astronomers and mathematicians, who had discovered and elaborated the whole science of navigation…’

Eventually the Snark made her first landfall, just as planned:

‘ “That island is Maui”, we said, verifying by the chart. “…We’ll be in Honolulu tomorrow. Our navigation is all right.” ‘

[Quotes from The Cruise of the Snark by Jack London]