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Bird migrations go astray: caused by magnetic field disturbances? + Flapping drones

#1
C C Offline
Feathered robotic wing paves way for flapping drones (vehicles)
https://www.eurekalert.org/news-releases/976577

Birds fly more efficiently by folding their wings during the upstroke, according to a recent study led by Lund University in Sweden. The results could mean that wing-folding is the next step in increasing the propulsive and aerodynamic efficiency of flapping drones.


When migrating birds go astray, disturbances in magnetic field may be partly to blame (travel)
https://newsroom.ucla.edu/releases/birds...etic-field

RELEASE: It seems logical enough that bad weather can sometimes cause birds to become disoriented during their annual fall migrations -- causing them to wind up in territory they're unaccustomed to. But why, even when weather is not a major factor, do birds travel far away from their usual routes?

A new paper by UCLA ecologists explores one reason: disturbances to Earth's magnetic field can lead birds astray -- a phenomenon scientists call "vagrancy" -- even in perfect weather, and especially during fall migration. The research is published in Scientific Reports.

With North America's bird populations steadily declining, assessing the causes of vagrancy could help scientists better understand the threats birds face and the ways they adapt to those threats. For example, birds that wind up in unfamiliar territory are likely to face challenges finding food and habitats that suit them, and may die as a result. But it also could be beneficial for birds whose traditional homes are becoming uninhabitable due to climate change, by "accidentally" introducing the animals into geographic regions that are now better suited for them.

Earth's magnetic field, which runs between the North and South Poles, is generated by several factors, both above and below the planet's surface. Decades' worth of lab research suggests that birds can sense magnetic fields using magnetoreceptors in their eyes. The new UCLA study lends support to those findings from an ecological perspective.

"There's increasing evidence that birds can actually see geomagnetic fields," said Morgan Tingley, the paper's corresponding author and a UCLA associate professor of ecology and evolutionary biology. "In familiar areas, birds may navigate by geography, but in some situations it's easier to use geomagnetism."

But birds' ability to navigate using geomagnetic fields can be impaired when those magnetic fields are disturbed. Such disturbances can come from the sun's magnetic field, for example, particularly during periods of heightened solar activity, such as sunspots and solar flares, but also from other sources.

"If the geomagnetic field experiences disturbance, it's like using a distorted map that sends the birds off course," Tingley said.

Lead researcher Benjamin Tonelli, a UCLA doctoral student, worked with Tingley and postdoctoral researcher Casey Youngflesh to compare data from 2.2 million birds, representing 152 species, that had been captured and released between 1960 and 2019 -- part of a United States Geological Survey tracking program -- against historic records of geomagnetic disturbances and solar activity.

While other factors such as weather likely play bigger roles in causing vagrancy, the researchers found a strong correlation between birds that were captured far outside of their expected range and the geomagnetic disturbances that occurred during both fall and spring migrations. But the relationship was particularly pronounced during the fall migration, the authors noted.

Geomagnetic disturbances affected the navigation of both young birds and their elders, suggesting that birds rely similarly on geomagnetism regardless of their level of migration experience.

The researchers had expected that geomagnetic disturbances associated with heightened solar activity would be associated with the most vagrancy. To their surprise, solar activity actually reduced the incidence of vagrancy. One possible reason is that radiofrequency activity generated by the solar disturbances could make birds' magnetoreceptors unusable, leaving birds to navigate by other cues instead.

"We think the combination of high solar activity and geomagnetic disturbance leads to either a pause in migration or a switch to other cues during fall migration," Tonelli said. "Interestingly, birds that migrate during the day were generally exceptions to this rule -- they were more affected by solar activity."

Although the researchers only studied birds, their methods and findings could help scientists understand why other migratory species, including whales, become disoriented or stranded far from their usual territory.

"This research was actually inspired by whale strandings, and we hope our work will help other scientists who study animal navigation," Tingley said.

To make the research more accessible to the birdwatching public, Tonelli developed a web-based tool that tracks geomagnetic conditions and predicts vagrancy in real time. The tracker is offline during the winter, but it will go live again in the spring, when migration begins again.
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#2
Zinjanthropos Online
Even if there are no magnetic field disturbances, what is it exactly that tells a bird the best place to fly to? Is there a preferred magnetic field, one that’s associated with better weather, environment, food etc? I would imagine a magnetic field is just that, no differences other than when disturbed. Is there a signature magnetic field they look for?

Could birds be following in the steps of their dinosaur ancestry? Did not feathered dinosaurs migrate before birds evolved? How did the big lumbering beasts do it? Birds can see farther, get somewhere quicker and even turn around should it be necessary I would think. What about older birds that know the way just by using landmarks? Trust the older bird’s knowledge over built-in navigational equipment, what’s best?

No doubt birds can go off course and lose their bearings for number of reasons. Occasionally they end up in a better place. Not guaranteed. We’ve had Pelicans show up here in Niagara.

http://joshvandermeulen.blogspot.com/201...agara.html
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#3
confused2 Offline
(Jan 14, 2023 02:21 PM)Zinjanthropos Wrote: Even if there are no magnetic field disturbances, what is it exactly that tells a bird the best place to fly to? Is there a preferred magnetic field, one that’s associated with better weather, environment, food etc? I would imagine a magnetic field is just that, no differences other than when disturbed. Is there a signature magnetic field they look for?

Could birds be following in the steps of their dinosaur ancestry? Did not feathered dinosaurs migrate before birds evolved? How did the big lumbering beasts do it? Birds can see farther, get somewhere quicker and even turn around should it be necessary I would think. What about older birds that know the way just by using landmarks? Trust the older bird’s knowledge over built-in navigational equipment, what’s best?

No doubt birds can go off course and lose their bearings for number of reasons. Occasionally they end up in a better place. Not guaranteed. We’ve had Pelicans show up here in Niagara.

http://joshvandermeulen.blogspot.com/201...agara.html

These migration routes might well have a geological timescale to them. I'm fairly sure I've seen that the birds now migrating over the Himalayas started doing it when they were much lower or possibly not even there - which is how they evolved such amazing adaptations to high altitude flight. I can't find a link for this though.
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#4
Zinjanthropos Online
(Jan 14, 2023 06:41 PM)confused2 Wrote: These migration routes might well have a geological timescale to them. I'm fairly sure I've seen that the birds now migrating over the Himalayas started doing it when they were much lower or possibly not even there - which is how they evolved such amazing adaptations to high altitude flight. I can't find a link for this though.

Bar headed goose. This what you’re referring to C2?

https://www.pnas.org/doi/10.1073/pnas.10...0%938%20h.

Then we have birds migrating over oceans. Have read they depend more on weather, wind conditions. Can’t see the magnetic field being that big of a guide and maybe birds do use them somewhat. However engaging large bodies of water and mountains seems like it should prevent/deter the use of magnetic fields. Always wondered if the Ruby Throated Hummingbird migrates over Lake Ontario instead of going around and I’m thinking they used the prevailing west winds to do it, at least in the spring. However they need to go against wind in fall.

Migrating songbirds fly into tall buildings. Would those that make it past these obstacles be better equipped than their lower flying brothers and sisters? Will it be passed on eventually and tall buildings become less of a problem?
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#5
confused2 Offline
Z. Wrote:Bar headed goose.

Basically yes - but I was hoping someone other than me would confirm that the Himalayas grew up underneath their route rather than that they initially chose to fly over a range of mountains that high. There's others but I think the bar headed goose is the most spectacular at zooming over at high altitude.

Quote:The age of the largest continental collision on Earth has long been controversial, with age-estimates ranging from at least 59 to 34 million years ago,
https://www.upi.com/Science_News/2015/11...447091311/

I suspect what I am remembering may well predate the Internet - not a good or verifiable source.
I like the possibility of them flying the same route for maybe 60 million years or more with the rise of the Himalayas being no more than a minor inconvenience.

I can say that before they get all their feathers young seagulls are as different as any two children could possibly be. If this continues into adulthood and to some/most/all species then any flock of birds is a group of individuals agreeing to do the flocking thing.

As the Himalayas rose there'd have been birds thinking it was ridiculous to carry on and they'd either die or go on to become the sorts of geese or birds you find in other places.
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#6
C C Offline
(Jan 14, 2023 11:15 PM)confused2 Wrote:
Z. Wrote:Bar headed goose.

Basically yes - but I was hoping someone other than me would confirm that the Himalayas grew up underneath their route rather than that they initially chose to fly over a range of mountains that high. There's others but I think the bar headed goose is the most spectacular at zooming over at high altitude.

This author at least contends that the mutation did happen millions of years ago. The gov paper claims a vertical growth rate of 10km per million years for the Himalayas, but other factors are obviously mitigating that.

The Bar-Headed Goose, by Thomas H. Jukes ... published 1992
http://publications.americanalpineclub.o...aded-Goose

EXCERPT: Millions of years before George Leigh Mallory attempted to ascend Everest “because it was there,” a remarkable bird had found its way over Everest’s summit, thanks to winning a prize in evolution’s lottery. The bird was the bar-headed goose, truly a Reinhold Messner of the avian world.

[...] This story is about a hemoglobin mutant that made a goose into a mountaineer several million years ago.

[...] When this happened to the ancestor of the bar-headed goose, the bird found it could fly higher and further than before, so that it could live in places where ordinary geese could not compete with it. The key mutation was changing from proline to alanine at the 119th position in the alpha hemoglobin chain. Several other mutations took place in other locations, but these had no effect on oxygen transport; they were so-called “neutral” mutations.

This sounds like an unusual and unique event, but, very remarkably, a similar but not identical mutation took place in the Andean goose, thus making it possible for this goose to fly at 9000 meters, far above the usual enemies of geese. This time, the mutation was from leucine to serine at position 55 of the beta chain.
- - - - - -

The Himalayas: Two continents collide
https://pubs.usgs.gov/gip/dynamic/himalaya.html

EXCERPT: The Himalayas and the Tibetan Plateau to the north have risen very rapidly. In just 50 million years, peaks such as Mt. Everest have risen to heights of more than 9 km. The impinging of the two landmasses has yet to end. The Himalayas continue to rise more than 1 cm a year -- a growth rate of 10 km in a million years! If that is so, why aren't the Himalayas even higher? Scientists believe that the Eurasian Plate may now be stretching out rather than thrusting up, and such stretching would result in some subsidence due to gravity.
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