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Tuesday 24 May 2016

Migration

At least 4,000 species of bird are regular migrants, which is about 40 percent of the total number of birds in the world.

When Christopher Columbus crossed the Atlantic Ocean, he remembered that the Portuguese had discovered the Azores by studying migrating birds. So the crafty captain decided to follow the birds' flight line.

For millennia, Europeans didn't really understand where birds went in the winter. Scientists finally solved the mystery in 1822 when a stork impaled by Central African spear was discovered by a hunter near Mecklenburg, Germany.

A Polish environmental charity put a SIM card in a GPS tracker to follow the migratory pattern of a white stork named Kajtka, in April 2017. They lost track of the stork and later received a phone bill for $2,700; someone in Sudan had taken the SIM from the tracker and made over 20 hours of calls.

A female shorebird was tracked by satellite tag and found to fly 7,145 miles in nine days from Alaska to New Zealand without stopping - the longest non stop bird migration ever recorded.

Arctic terns take the prize for the longest migration of any bird. It can fly a round trip from its Arctic breeding grounds to the Antarctic and back. The shortest distance between these locations is 19,000 km (12,000 mi).

An Arctic tern from the Farne Islands off Northumberland, England clocked up the longest migration ever recorded. The tiny bird's meandering journey to Antarctica and back saw it clock up 59,650 miles, more than twice the circumference of the planet.

Arctic Terns

Migratory species of crane can fly at heights of up to 32,000 feet, a record among birds.

In ancient times it was thought that swallows hibernated in winter. In fact they migrate, flying 12,000 miles to southern Africa and back, covering 200 miles a day and crossing two continents and 14 countries.

The Serengeti 'great migration' is an annual circular pattern of movement with some 1.7 million wildebeest and hundreds of thousands of other large game animals including gazelles and zebra.  It begins and ends in the Ngorongoro Conservation Area of the southern Serengeti in Tanzania and is a natural phenomenon determined by the availability of grazing.

Wildebeests crossing the river during the Serengeti migration

A "super generation" of monarch butterflies migrate more than 3,000 miles from northern USA/Canada to Mexico in the fall. The following spring, it takes four or five generations of monarch butterflies to complete the annual return journey.

The grey whale migrates 12,500 miles from the Arctic to Mexico and back every year.

Many species in the sea have a daily migration. Plankton go up for the day where there is light, and down at night, where they are less easy to find.

Chunyun refers to the travel season surrounding Chinese New Year. It starts around 15 days before New Year's Day and lasts for roughly 40 days. During this period, there's a massive movement of people within China as migrant workers in the cities grab the chance to return home to see their families. It's considered the world's largest annual human migration.

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