migration

Showing 5 posts tagged migration

Why do birds often fly in a “V” shape formation? Researchers at the UK’s Royal Veterinary College have gathered data from individual ibises in a migratory flock to study why this pattern is so popular: their relative position and wing flap timing gives them extra lift from the upward motion of air created by the bird ahead of them.

In 2011, as part of a reintroduction programme, captive-bred ibises following an ultralight aircraft to their wintering grounds arranged themselves in the shape of a V. Data loggers on their backs captured every position and wing flap, yielding the most compelling experimental evidence yet that birds exploit the aerodynamics of the familiar formation to conserve energy.

Above, this lovely Nature Video tells the study’s story: Come fly with me. You can read more about this upwash exploitation at Nature or The New York Times, or watch a summary video at NPR.org.

Related watching: take a ride on an eagle’s back, TED Ed’s Bird Migration, A Perilous Journey, and behind the scenes of the BBC’s phenomenal Earthflight.

The daring 5-mile (8-kilometer) migration of Christmas Island’s adult red crabs begins with the wet season’s arrival in October or November. The crabs’ goal: move from the forest to the beaches en masse, breed, drop their eggs into the water, just before the turn of the high tide, and then return to center of the island.

This massive move of 50 million creatures is a spectacular sight. It’s also a challenge to keep them safe. As shown in the video above, Christmas Island National Park rangers do an immense amount of work to protect these animals as they traverse the roads that cross their path: cleaning up debris, constructing temporary fences, raking crabs across roads to avoid traffic, and closing some roads are all a part of the job.

There are more crabs crawling around in the archives, including migrating horseshoe crabs, a mass migration of Caribbean hermit crabs, and what it looks like when the Christmas Island red crab larvae hatch and head back for dry land.

Called living fossils, horseshoe crabs are harmless creatures that have been swimming oceans for a few hundred million years. They predate dinosaurs and are closely related to spiders or scorpions. Every May and June, they crawl onto the beaches “from the Yucatan to Maineto mate and lay eggs in the sand in mass numbers.

At the same time, hungry Red Knot birds on the way to the Arctic from the southern tip of South America are looking for those millions of little green horseshoe crab eggs so that they can eat. The nourishment helps them gain energy so that they can finish their long migration and breed, as well.

In this KQED Science on the Spot, Rendezvous With Horseshoe Crabs, learn about these two species and what local teams are doing to protect the balance of their interdependency.

To learn more about horseshoe crab conservation efforts, check out Science Friday’s report: Beach Season For Horseshoe Crabs.

Photographer Steve Simonsen films an epic Caribbean hermit crab mass migration at Nanny Point, St. John, in the U.S. Virgin Islands. This video has gone viral, and it’s pretty clear as to why! How many thousands and thousands and thousands of crabs are on this beach?!

From ABC News

Hermit crabs, also known as soldier crabs, are found throughout the Caribbean islands and take part in a great migration en masse annually in August to mate. The crustaceans travel to the beach, leave their shells and enter the water to lay eggs, according to Smithosianmag.com. After spending two minutes in the water, Simonsen said the crabs turn around, return to land and make their way home.

People who live on St. John know this happens in August. I’ve never been able to see it or know when it happens,” said Simonsen, who plans to study the creature’s migrations, moon phases, tides and stake out beaches next August to see the phenomenon again.

You can read more about "crazy crab migrations" on SmithsonianMag.com.

Thanks, @ceili.