As always on this boulevard, the faces were young, coming annually in an endless migration from every country, every continent, to alight here once in the long journey of their lives.

BRIAN MOORE (1921-99)

Migration

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Woodcock Pilots


One of the smallest birds to migrate is the goldcrest, the smallest bird in the UK. Historically, people couldn't believe that they flew such large distances on their own, and thought they must hitch a lift on the backs of woodcock. They were nicknamed 'woodcock pilots' as a result. 

Every spring the North American Blue Grouse makes the same migration to its breeding grounds: 300 yards, downhill, on foot (from the pine forest down to deciduous woodlands to build a nest and feast on berries and insects). In the autumn it wanders back up the mountain. The 4-ounce Arctic Tern flies about 44,000 miles a year, or about 1.5 million miles in a lifetime: equivalent to going to the Moon and back, three times.

Until 1995, nobody knew where the endangered Spectacled Eider Duck migrated to in winter. For 120 years it was a mystery until a study was carried out which involved implanting satellite transmitters in the birds revealing that they spend the winter in huge groups on the Bering Sea. During winter the sea freezes over but the Spectacled Eiders are able to keep open a hole in the ice by constantly moving around and diving to the bottom. This movement prevents the water from freezing and allows the ducks to eat moss on the sea floor.
 
The longest non-stop migration flight is that of the bar-tailed godwit - 7,258 miles (11,680 km) from Alaska to New Zealand.

Irresistible Urge


A bird's irresistible urge to migrate is called zugunruhe (from the German zug, ‘movement’, and unruhe ‘restlessness’), and can be studied by using an Emlen Funnel: the bird is put inside the funnel, which has netting over the top so that it can see the sky but not get out. On the floor there's an inkpad, so it gets ink on its feet. Up the slopey sides there is paper - so its attempts to get out are recorded as footprints, and you can see whether it is trying to get out in a particular direction.

You can experiment by using a planetarium to change the apparent orientation of the sky (where the Sun & stars seem to the bird to be) and by manipulating the magnetic fields it is subjected to. 

Four Generations


For a really extreme migration, the Globe Skimmer dragonfly takes some beating. It travels from Southern India clear across the Indian Ocean to Southern Africa, and back again – taking four generations to complete the round trip of 11,000 miles. Scientists tracked them by attaching tiny radio transmitters to their thoraxes with eyelash adhesive and superglue.

Millipedes migrate in huge numbers. These migrations can cause Australian trains to run late; trains run over these insects causing millipede-goo to cover the tracks - subsequent trains cannot get any traction on the slippy surfaces.

In crowds, increased touching of locusts' hind legs by other locusts triggers a migratory urge. Once populations fall, they become solitary again.

Missing Albatross


In 2005, an albatross race in which 17 birds were tracked electronically on their annual migration from Australia to Africa ended when all 17 of the albatrosses went missing.

DAVID ATTENBOROUGH

People must feel that the natural world is important and valuable and beautiful and wonderful and an amazement and a pleasure.

The Great Migration


The great wildebeest migration is one of the most spectacular wildlife events on the planet. Approximately 1.7 million wildebeest cross the Serengeti and Masai Mara with 400,000 zebra, 200,000 gazelles and and 12,000 eland; a total of over well over 2 million migrating animals. By May all the Serengeti's wildebeest are moving north to seek fresh grazing and water.

The wildebeest have to cross the Mara River in the Maasai Mara where crocodiles prey on them. They arrive in their tens of thousands and wait to cross. Their numbers build for days but often, for no apparent reason, they turn and wander away from the water’s edge. Eventually they choose a crossing point which can vary from year to year.
 
In the Maasai Mara they will be hunted by larger carnivores; it has has one of the largest densities of lions in the world.

By late October, the first of the rains are falling on the Serengeti’s plains, filling waterholes and bringing new growth, the wildebeest start heading south again.

Microlight Bonding


The French ornithologist Christian Moullec has taught a group of 30 endangered Lesser white-fronted geese a new migratory path. Bonding with them as goslings, he led them the 1,000 miles between wildlife sanctuaries in Germany and Sweden flying a microlight, a journey they repeated the following year on their own.

They are now so well trained that Moellec and his 'flock' regularly appear as the star turn at airshows.

Ladybirds migrate from Sicily to Malta.

Sea cucumbers appear to migrate up and down in the ocean. Nobody knows when or why they do it.

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The tiny ruby-throated hummingbird crosses the 525 mile Bay of Mexico in just 20 hours in its winter migration.

Whales have the longest migration of any mammal, humpback whales have been recorded travelling 5,100 miles.

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Migrating flocks of European white storks can stretch for lengths of up to 125 miles.

Male and female walruses migrate in separate herds.