Dutch Eagle Fan wrote:
Article, in Dutch so you need Google to translate it, about a bar-tailed godwit (Limosa lapponica) that migrated from Alaska to New Zealand, setting a new world record!
English translation! WOW! Thanks DEF! Bar-tailed godwit pulverizes world record flying nearly thirteen thousand kilometers across the Pacific Two quarreling bar-tailed godwitsThe record "non-stop long-range bird flying" has been set by a bar-tailed godwit, nearly eight thousand miles across the Pacific Ocean. How do they do that?!
Rob Buiter10 oktober 2020, 21:04
The new record holder has the poetic name "4BBRW", after the colors blue, blue, red and white, from the rings on its legs. It is a male of the bar-tailed godwit that was caught in New Zealand almost a year ago and fitted with a transmitter. On September 16, he left Alaska for a trip southwest. On September 27, he had the more than ten-year-old record of non-stop flying of its fellow "E7" of 11,600 km. And when he arrived in a bay east of Auckland, New Zealand, he broke that record: 12,854 km!
The flight of these and other extreme migratory birds can be followed on the website of the Global Flyway Network, a collaboration of migratory bird researchers led by Groningen professor Theunis Piersma. “What these birds do is really unimaginable,” he says, calling from the car he uses to follow Dutch spoonbills on their trek to Africa.
Refuel on the coastPiersma: “Those bar-tailed godwits first fly from their breeding grounds on the tundra of Alaska a few hundred kilometers to the tidal flats on the coast. There they eat completely full of shellfish and seaweed. At one point, they consist of almost half fat. A bar-tailed godwit with an empty tank weighs nearly three ounces, but on departure from Alaska, they weigh more than a pound! Where they normally can just fly straight up, they have to take a run up to get loose, just like a swan on the water, that's how heavy they are when they leave. By the time they arrive in New Zealand, the tank is really empty; then they are half as heavy again. ”
In order to be able to carry such a large amount of fuel, birds save on the size of their organs during migration. Piersma: “That seems to be controlled by an internal clock. With another long-distance hiker, the knot, we see that around the pull time they almost automatically get bigger muscles, and organs like stomach and liver get smaller. That is true even if we keep them in a cage, where they cannot fly great distances to train their muscles. That greasing is also well established. Even if we change the day-night rhythm of the birds with the help of lighting in the cage, the birds still prepare for the migration by eating extra.”
The flight record of the bar-tailed godwit. Image Global Flyway NetworkEconomical with fuelThe enormous distances that birds can travel non-stop continue to amaze scientists time and again. In 1950, American bird researchers wrote in scientific literature that a mere thousand kilometers across the Gulf of Mexico must be an impregnable barrier for a bird. Research with ringed birds in the years after showed that even three thousand miles was a feasible hurdle. In 2008, the bar was set more than twice as high. Bar-tailed godwits from Alaska that received a transmitter in their belly were found to be able to fly 11,000 km across the Pacific Ocean in eight days. Now it appears that we can go one step further: 12,854.
A major key to this bizarre achievement is the modest amount of energy the birds appear to need to move forward. Swedish biologists calculated a few years ago that a bar-tailed godwit uses only 0.42 percent of its body weight in fat to fly nearly 60 kilometers per hour for an hour. That is the lowest fuel consumption of all the flying animals they examined. A hummingbird, for example, consumes nearly five times as much - up to 2 percent of its body weight in "fuel" to fly for an hour.
Several godwitsThe bar-tailed godwits that fly from Alaska to New Zealand are of a different subspecies than the bar-tailed godwits that occur in our Wadden Sea in spring and autumn. They fly from their breeding grounds in the tundra of Siberia to the wintering grounds in West Africa. Especially in the spring, on their way to the breeding area, these birds use the Wadden Sea as a filling station. “Then they eat mudflats here,” says Theunis Piersma. "Our Wadden Sea is an essential gas station to complete that hike."
The red-haired "tundra groat" is somewhat related to our national bird, the "meadow groat". “We have also been giving those birds miniscule transmitters for several years now, with which we can follow them on their migration,” says Piersma. “In this way, all these" world godwits "teach us not only about the migration, but also, I think, about the state of the world. For example, from the changing migration of bar-tailed godwits to Siberia, we can clearly see how the tundra there is warming much faster than any part of the world. And the black-tailed godwits clearly show in their migration and distribution the effects of our intensive agriculture on the landscape. ”
Mysterious navigationTo fly from Alaska to New Zealand across the vast Pacific Ocean, you need at least a good compass and a map. It seems that the bar-tailed godwits leaving Alaska also have a good weather map in their pocket, Piersma says. “If you look at the routes of the different birds on the map, you see that they are certainly not taking the shortest route, and sometimes also make big turns. We can only understand these routes if we project the high and low pressure areas with the corresponding wind directions on the map. Then the birds appear to make perfect use of favorable wind directions. ”
But tailwind or not, if you are flying over an endless ocean, without visible landmarks, then you have to somehow know where you are and which direction to take? “That orientation and navigation remains a mystery,” Piersma must admit. “If the birds only had a compass needle in their head or in their eyes, they wouldn't make it. They must also have some sort of GPS to know where they are at any given time. They probably make some use of the earth's magnetic field, which differs from place to place, but also of the polarization of the sunlight and the stars. ”
And then sleepAn empty tank after more than 10,000 kilometers of flying is one thing. Bird researchers in New Zealand now know that bar-tailed godwits need to make up more shortages. Piersma: “During the first few days these birds sleep a lot more than their peers who have been on the spot for some time. Even if the food appears on the mud flats at low tide, they just continue to sleep. It seems that after an extreme hike, lack of sleep is an even higher price than lack of fuel. ”
Also read:
Why do birds migrate from Africa to the Arctic?
Migratory birds nesting in the far north are less likely to suffer from predators stealing their eggs, it seems. Is that why they go to all that trouble to fly thousands of kilometers back and forth every six months?
https://www.trouw.nl/nieuws/waarom-trek ... ~ba0dcffd/