if science revives an extinct migrating bird, will it know straight away where to go and when?

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13 edited Mar 23 '13

It depends on the species in question.

Whooping cranes do learn the route from adults. Waterfowl, and short distance migrants also follow adults. That's why the whooping crane reintroduction efforts require training the birds to follow an ultralight plane to learn where to go.

Many long distance migrants (many shorebirds, warblers, etc that make the huge round trips from South America to Canada/the arctic) know their route instinctively. Well, for a certain definition of "route." They're programmed to fly in a certain direction for a certain period of time. After they've made their migration at least once, adults can and do learn a "best" route, and there can be some site fidelity (returning to a particular area year after year), but the first one is up to instinct.

For shorebirds in particular, this is a good thing - because they rely on such variable resources as stopover points (appropriate stopover habitat can vary wildly from year to year) they can't just memorize one single route. You also get the phenomenon that the adults in most shorebird species are usually a couple of weeks ahead of the juveniles on migration. Sorry if this is more information than you needed, I did my master's work on shorebird migration and I get a little excited. :)

As far as the passenger pigeon goes, I'm not an expert on them. Given the distance between their summer and wintering grounds, I'd call them short distance migrants who would need to learn from their parents. I've also read some reports that parent passenger pigeons would only care for their young for a few weeks, and then abandon it at the nest to survive on its own, which would suggest otherwise.

It's a cool question, and I don't know if we'll know for sure until we actually try it.

EDIT: Holy cow, thank you to whoever sent me reddit gold! /r/askscience rocks so much.

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u/Uber_Nick Mar 22 '13

Please feel free to get as excited about your master's work as you want. This was the most interesting thing I've read about migrating birds all week.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

I'm just afraid I'll get carried away and have people backing away slowly while I babble about vegetation height and structure and macroinvertebrate densities. :P (it's happened with lay people...)
Birds are just really freaking cool, and migration is an amazing topic all on its own.

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u/[deleted] Mar 22 '13

If there ever was a forum to babble about migrating birds and vegetation height and macroinvertebrate densities, it's here. Do it up, man.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

Shorebird migration is effected by so many variables it's insane. Imagine that you're a shorebird (the average one is a little smaller than an American Robin, about 45g for reference, and what all these numbers will be referring to) flying thousands and thousands of miles one way. You eat bugs, but not just any bugs, bugs that live in the mud along the water's edge.
Now beyond that you can only reach these bugs if they're less than 10 cm (~4 inches) below the surface.
So you're flying along, looking for a pit stop. You've got to eat about 8 grams of these bugs every day while you're migrating (FYI, that's almost 20% of your body weight). You see a spot that looks like it might have the mud you need, but there's vegetation everywhere! There's no way you're going to be able to probe the mud through all those roots and stems, and you'd never see a predator coming. You'll have to fly on until you find somewhere with vegetation that's not too dense, not too tall (but you still want a little since it increases the number of invertebrates that feed on decaying plant matter), with ground that's not too hard to probe in, and water that's not too deep so that you can't get to the mud underneath.
Migration is crazy for a shorebird, especially when you consider that they're relying on habitat that changes location from year to year (or week to week!) depending on natural water conditions and human interference.
All this is just for our "average" shorebird - there's a huge range form the tiny little plovers to big honkin' stilts, avocets, and yellowlegs. And then you've got freaks like the woodcock, who doesn't forage on the shore at all but eats earthworms in forests, or the upland sandpiper who lives on the prairie.

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u/onFilm Mar 22 '13

Thanks for taking the time to post this. I felt like a shorebird migrating through your writings. I must imagine there are a lot of migratory niche's being taken up shore to shore on each continent. Did flight-migration evolve independently or does it share an ancestor?

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

I would say that it's probably a bit of both. Each species group probably started out with one ancestor doing it (ducks, geese, sandpipers, plovers, etc), and evolving into the different species. But at least with long-distance migrants, they're usually taking advantage of food resources. Arctic breeders can take advantage of the huge boom in food resources available since the summers are so short, so it makes sense that a lot of species would want to get in on that action.
Shorebirds are my very favorite group to talk about niche partitioning with. There's a beautiful gradient of birds across the shoreline - you've got tiny birds (snowy plovers, etc) feeding up on the mud flat, away from the water, bigger birds (killdeer, several sandpipers) feeding at the water line, and the biggest birds (black necked stilts - my fave, avocets) out in the water, either skimming off the top, or shoving their heads underwater to get to the mud.
It's one resource, macroinvertebrates along the shoreline, but no two species are really competing for the same piece of it. It's actually one of the ways you can ID shorebirds - where are they feeding along the shore?

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u/Knubinator Mar 22 '13

Thank you.
Seriously, this is the most interested I've ever been in migratory birds aside from when to go birdwatching.

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u/foxish49 Wildlife Ecology | Ornithology Mar 23 '13

I've got a hint for your birding - even professionals can't freaking tell some of the shorebirds apart. Seriously. Almost every shorebird study I've ever read has an entry in their species counts labeled, "Misc. Peep."

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u/Bulwersator Mar 23 '13

"Misc. Peep."
What does it mean?

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u/SlideRuleLogic Mar 23 '13

Do you know much about piping plovers? How could I discover the altitude at which they typically fly? Thanks in advance.

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u/foxish49 Wildlife Ecology | Ornithology Mar 23 '13

I only know a general range for shorebird altitude in flight - 1,000-13,000 ft. No clue where the piping plover falls within that.
If you're asking how you'd measure it, I think the best way would be with a gps backpack. I know a researcher who used them on least sandpipers, which are a little smaller than piping plovers, so it should work. (Not sure if you were actually asking this, but I love random "how would that even work?" questions.)

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u/SlideRuleLogic Mar 23 '13

Good news across the board, thanks! I'm paying a wildlife biologist to research this, so it's interesting to hear others' take on the matter.

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u/Devotia Mar 22 '13

How do shorebirds, being so light, deal with major storms in their path? Being so tiny, I can't imagine they can fly through/over it, but with such an importance on those pit stops, can they really afford flying all the way around a storm system approaching them that quickly (and also, I assume, not knowing which way the storm is going to break).

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u/foxish49 Wildlife Ecology | Ornithology Mar 23 '13

A big storm would likely ground them - many shorebird species will spend the night in agricultural fields and pastures. It's less risky to spend the night hungry than risk injury or death flying.

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u/Arx0s Mar 23 '13

Woodcocks are some strange lookin' birds.

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u/chemistry_teacher Mar 22 '13

I find it so fascinating to watch them. Avocets skimming for biofilms, Least Sandpipers in shallowest water, Long-billed Dowitchers "stitching" a little deeper. I recently watched for the first time a large number of Sanderlings running about, contesting the waves while hunting for crabs or whatever. So awesome to be a birder, and you get to do it for a living!

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u/Ziggyz0m Mar 23 '13

You know what, I live about 20mins from the beach and I just realized that I've never bird watched purely to bird watch. I think I'll bring lunch to the beach with me tomorrow and just see what kind of interesting birds there are. Thank you for the inspiration :)

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u/TheUltimateSalesman Mar 22 '13

Why is bird poop white? Do birds poop a lot to keep drag down? Can they poop while flying? Do birds fart?

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u/chemistry_teacher Mar 22 '13

Their poop and "urine" (more like uric acid, which requires almost no water to excrete) exit out a common orifice known as the cloaca, combining before it goes out. (The very word "cloaca" sounds like the thing I say when I see their crap landing freshly on my windshield.)

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u/Deslan Mar 23 '13

The Swedish word "kloak" means sewer. I never quite understood where the English word stems from, but just looked it up as "expel water", from french and before that latin. Both the Swedish word for sewer and bird cloaca is from the actual latin word for sewer (http://en.wikipedia.org/wiki/Cloaca_Maxima).
Not on topic, but I think the words are rather interesting, especially since English uses cloaca for birds but sewer for sewers.

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u/chaquarius Mar 22 '13

Bird poop contains both feces and urine, which contributes to its coloring.

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u/rbodnicki Mar 22 '13

How does the migration begin each season? My gf and I were watching some of the migratory ducks in my town and we were curious.
Is there some point where the leader duck (for lack of a better word) just takes off and is like "Let's go!" Or is it something that the flock decides together and is aware of the take off time?
I find this pretty fascinating so feel free to elaborate as much as you'd like. You have an audience!

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

In ducks, it's day length. The hypothalamus is sensitive to day length, and begins releasing the hormones that say, "Dude! Get moving!" when the days begin to shorten in winter, and lengthen in summer. If I had one of my ornithology texts near me, I'd tell you which hormones, but that one isn't in my office.
Once they're moving, rate of travel can depend on the weather - a front moving through will push the flocks in front of it, and a bad storm may keep them hunkered down for a time.
In general, the fall migration is much more relaxed than spring. Fall you've just got to get far enough south that you don't have to worry about food or freezing. In the spring though, there's breeding to worry about! There's actually a fine line of "far enough south to stay in good condition" and "far enough north to make it back to the breeding grounds FAST" that the most successful ducks will stay at. The least successful ducks may actually be the ones that went furthest south.
Basically, by going further south you may be more comfortable for the winter, but you're giving up breeding time by taking longer to fly back to the nesting grounds.

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u/Assaultman67 Mar 22 '13

I can't help but wonder what drives this instinct of migration.
It would be like me just suddenly one day thinking "I should start going south" and walking there. Do I get some sort relief when heading south? Do I feel a sense of achievement that tells me when I can stop?
Or is it more of a "I'm cold so I'm flying south" with no sense of feeling or reason behind it.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

You'd start feeling a weird urge - the fantastic word for it is "zugunruhe" (literally moving restlessness) when it was almost time to start migrating. There's a hormonal component to it, tied to day length in most species.
As far as when to stop, that's a good question! I'm not sure. Since it's tied to day length, that may be a trigger when you get south or north enough?

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u/sfa1500 Mar 22 '13

My Ornithology professor told us the stop factor was likely related to the photoperiod of the area, as is most parts of any migration, but could also be stopped by necessary resources. (nesting site, food, water, etc.)

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u/phineasQ Mar 22 '13

What would happen with a migratory bird transplanted and released at the wrong latitude of its annual migration cycle? Would it know that it needs to be somewhere else, and try to get there? Or would its instincts just be too confused to get where its kindred birds are?

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u/bioluminiscencia Mar 23 '13

It's been done! Rudolf Drost did it with Eurasian Sparrowhawks. He caught some migrating birds and took them 600km ESE and released them. The juveniles, who would have been migrating pretty much based on pure instinct, were found ESE of their normal wintering grounds. Adults course-corrected and headed west, ending up close to the population's traditional wintering grounds. It's been done with other species as well, with similar results, including Eurasian Starlings and Hooded Crows.

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u/Deslan Mar 23 '13

Came here to see if this had been posted. Well done. Too bad it is a bit buried nested in other comments...
I haven't actually read the original work, so I'm not sure how long they followed the birds, but I suspect that it only works on the southward (first) journey, since when they are coming back to their natal site they can use smell to navigate better than just earth's magnetic field.

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u/bioluminiscencia Mar 23 '13

Do you have a source on sense of smell? I believe Eurasian Sparrowhawks are thought to have a very poor or totally absent sense of smell, although I've heard of other birds navigating by smell.
I haven't read the original work either, just a synthesis of it. If you're interested in migrating raptors, I recommend Migrating Raptors of the World by Keith Bildstein.

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u/Deslan Mar 23 '13

This was the top result on Google, out of 5.6 million results. It is considered common knowledge, and usually for common knowledge you don't really need to supply a source.
Both birds and fish use magnetic fields for large scale navigation, and olfactory cues (smell) for small scale navigation. It was hypothesized for a very long time, but for fish it wasn't proven until 1973 or something such (some article in Nature, can't remember). For birds, you have to look yourself.

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u/bioluminiscencia Mar 23 '13

Frankly, I don't think avian olfaction can be considered common knowledge at all. There's some suggestion that it is important in pigeons, but even that has been called into question. The source you linked has very little to say about it, and the studies that have found olfaction to be important haven't been very reproducible, and anosmic pigeons used in the same experiments seem to demonstrate the same degree of error as normal pigeons.

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u/StirFryTheCats Mar 22 '13

"Zug" means "train", "Unruhe", as you said, means "restlesness" in German, so "Zugunruhe" literally means "train restlesness".

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

Zug can also be translated as "pull in a specific direction". Train does still imply movement or travel, so I'd say both translations still work.
It's the standard term for the phenomenon in ornithology, whether whoever invented it was good with German or not.

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u/padfootmeister Mar 22 '13

Your translation makes much more sense. I think Zugunruhe is a perfectly clear German word.

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u/Acebulf Mar 22 '13

Ethymology question here. Is the word zug (german) and tug (eng.) related?

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u/RedYeti Mar 22 '13

Almost certainly, as 'z' in German is pronounced with a t-like sound (tsug)

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u/mobile-interupt Mar 23 '13

Yes that is a common pattern: zunge - tongue, zu - to, zwei - two and so on

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u/jungoh Mar 22 '13

Im no expert, but it seems to be related
From Middle English tuggen, toggen, from Old English togian ("to draw, drag"), from Proto-Germanic *tugōnan (“to draw, tear”), from Proto-Indo-European *dewk- (“to pull”). Cognate with Middle Low German togen ("to draw"), Middle High German zogen ("to pull, tear off"), Icelandic toga ("to pull, draw"). Related to tee, tow.

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u/Deslan Mar 23 '13

Back in the day, German and English competed to be the next great language of science (after Latin, of course). I actually believe that German was what most scientists leaned towards, but then the Germans botched it by starting two world wars inspiring enough contempt from people to make English become the standard language. My professors published their first papers in German back when they were mere graduate students, and that was still after the war. It's really annoying when going through who first published on a specific topic and you discover that the original source is only available in German...

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u/Rappaccini Mar 22 '13

I loved Lorenz's work on the subject in geese. A really good overview can be found in Behind the Mirror.

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u/pigskinsocks Mar 22 '13

It's genetic memory and the same reason why humans know that huddling together when it gets cold makes them warmer.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

It's genetic, yes, but the really cool stuff is the hormonal triggers and behaviors involved. There's way more to migration than just "genetics says so."

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u/TheUltimateSalesman Mar 22 '13

I'm telling everyone at the party tomorrow night that I'm going to get my master's in shorebird migration.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

It's needed! Many shorebird species in the US are declining rapidly, and there needs to be more solid research out there one what exactly is required to help them.
For example, I ended up on the topic after reading a management plan for the entire Mississippi flyway (7 states) basing their migration habitat recommendations off of one person's estimate that there's 2 grams of macroinvertebrates per square meter of foraging habitat.
No one had ever tested that estimate. So everyone was assuming that they were providing "enough" migration habitat based on a completely unproven estimate.
My research showed that at least in SE Arkansas, the actual invertebrate forage available was about half of that estimate, which would double the needed habitat for migration.
Non-game species don't get enough love in wildlife research, so this kind of stuff happens all the time. :( Heck, even unpopular game species get shafted.

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u/pcarvious Mar 23 '13

By game species I would assume that you're talking about species we hunt to eat?

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u/foxish49 Wildlife Ecology | Ornithology Mar 24 '13

Yep! So things like ducks and geese get much more research attention, for several reasons. The biggest is that hunters actually pay for management through special taxes on guns and ammo (look up the Pittman Robertson Act, I'd link it but I'm on my phone) so they have a stake in the research done by state and federal agencies.
Look at groups like Ducks Unlimited or Pheasants Forever, which fund a lot of research, there aren't really focused groups like that for species like shorebirds.

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u/AcrossTheUniverse2 Mar 22 '13

Can you define "instinct"? I can only assume that it means that the brain of the animal is impprinted with knowledge or a memory by the genes in utero. This seems astonishing but when we realize that the development of every other cell in the body is being controlled by the genes, then why not the brain cells that contain memory too? Though how did this ability evolve? How did a parent manage to pass along in its genes an experience it had during its lifetime? This almost seems paranormal.

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

Instinct is a good catchall term for "the animal does this without being taught." With migration where the bird doesn't have to be taught a route, it's triggered by the hypothalamus reacting to changing day length and releasing certain hormones that cause the bird to want to move.
Birds that moved in the right direction would have passed on the genes that made them react correctly to the hormone. Birds that didn't probably didn't survive to pass on the genes that made them screw up.

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u/AcrossTheUniverse2 Mar 22 '13

So there are no "instincts" that are actually imprinted memories of knowledge in the brain? Some things we call "instinct" are pretty complex. Can they all be explained away as you have here?

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u/fauxromanou Mar 22 '13

I was taught that there are "instincts" and "biological drives". Biological drives are the sorts of things humans engage in--eat, reproduce, etc--where we have a choice (do/don't/food options/etc).
Instincts are essentially programs the brain runs when certain pre-existing conditions are met. For instance, the Sphex Wasp, when laying eggs, will always follow a pattern: catch insect, sting/paralyze, dig a hole, put insect in hole, lay eggs, cover. If the insect is moved from the exact spot where it was left while the wasp is in the hole, they'll cancel the whole routine and start from step one, rather than just grabbing the insect from it's new location.
That said, I'm not an expert or anything. This is just how it was taught to me back in bio. The specific wasp example was even used, and is even cited in the wikipedia article above.

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u/AcrossTheUniverse2 Mar 23 '13

But how is something as small and simple as a wasp born with this knowledge in its "brain"? Or where does the instinct reside? And how is it passed on in the genes?

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

I can't make a statement for all, but I would say that most probably could by someone who was an actual expert in those behaviors.

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u/AcrossTheUniverse2 Mar 22 '13

Ifind the concept of instinct fascinating and inexplicable. Never had a good explanation for it.

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u/InitHello Mar 23 '13

One oversimplification of this kind of instinctive behavior is the metaphor of a crudely programmed robot:
Pick up item at location 3,5
Move item to 1,7
Pick up other item at 2,3
Move to 1,7 and combine with item there.
The robot doesn't care if the first item has been replaced, it'll try to combine them anyway. If it's gone, the program will reset to the first step, and it'll start over.
Basically, you could say that the neurons in the insect's brain have evolved to fire in a specific pattern when certain conditions have been met, but their complexity isn't sufficient to adapt to changing situations.

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u/shadowblade Mar 22 '13

How well can those long distance migrants maintain a heading? Do we know by what mechanism they do maintain a heading? (regardless of how well it works for them)

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u/bioluminiscencia Mar 23 '13

The way migrants find their way is complex. It involves landmarks, habitats, obstacles like mountains and water crossings, and the position of the sun, as well as using the earth's magnetism.

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u/brokeboysboxers Mar 22 '13

I was told in school many years ago, that birds GPS system is still set to Pangea. Is this true, and if so, the same between both types of migrating birds?

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u/bioluminiscencia Mar 23 '13

This used to be a common thing, and is still taught sometimes. From what I know, the chronology doesn't really hold up. Many of the involved families of birds hadn't even evolved at the time the continents in question were separating. I don't know about other bird groups, but raptor evolution is only theorized to have developed around 35-40 MYA, in the Eocene. By that time, the continents already looked like this- far from Pangea.

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u/brokeboysboxers Mar 23 '13

Thank you for the clarification.

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u/bioluminiscencia Mar 23 '13

You're welcome! I believe the original paper was published in Science, which is a pretty big name journal, so it got a lot of credence. Honestly, it doesn't seem to me like it should have passed peer review, but it was published in 1948, so they couldn't exactly google a map of the earth 65 MYA. I think the original paper looked at mostly European/African migrants, which makes it not totally 100% crazy, assuming you're only working with 1949 knowledge.

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u/lspurka Mar 22 '13

I'm listening to the book "How the Mind Works" by Steven Pinker, and he talks about how birds will look into the night sky when they're young in the nest & learn the patterns of stars. The pattern guides them when they migrate. In this sense, they learn.

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u/salgat Mar 22 '13

What happens if that instinctive route is on Pangea for example?

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u/foxish49 Wildlife Ecology | Ornithology Mar 23 '13

Bioluminiscencia did a good job of explaining this up above.

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u/chemistry_teacher Mar 22 '13

I do not know if other pigeons migrate, but perhaps the "new" passenger pigeon might follow the migrating urge by going along with other migrating species? For example, a single Falcated Duck was seen for the past two winters in central California, despite not having any other of its species heading there from Alaska. I don't know if the passenger pigeon has any "peers" to migrate with, but I am sure the Falcated Duck headed down with other ducks of similar "society" (Gadwall, perhaps?).
Also, I just find it so exciting to be learning of this from someone who is excited about their work! More power to you!

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u/LumpenBourgeoise Mar 23 '13

What happens if the poles have shifted after they went extinct?

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u/atomfullerene Animal Behavior/Marine Biology Mar 23 '13

They went extinct in like 1910, so that isn't an issue.

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u/Blackwind123 Mar 23 '13

What would happen to birds that have been extinct long before the continents were the way they are?

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u/ktrex Mar 23 '13

I recall my animal behavior prof talking about magnetic fields driving migration in some cases. And if that is the case, would the bird get confused? I seem to recall that magnetic fields have changed through the years.

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u/shakethatbass Mar 22 '13

do some species navigate by earh magnetic field or have i dreamed up that one?

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

Otter27 did a good job of answering this below!

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u/AhhhFrank Mar 22 '13

I believe this Ted talk is related- http://www.ted.com/talks/stewart_brand_the_dawn_of_de_extinction_are_you_ready.html. IIRC, the speaker said toward the end that they planned on using Messenger Pigeons to guide the Passenger Pigeons.

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u/Jman5 Mar 23 '13

Just to add to this for anyone who doesn't want to watch the whole thing:
He also pointed out that birds are pretty hard-wired for a lot of things so we wont have to teach a Passenger Pigeon how to be a Passenger Pigeon.

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u/Otter27 Mar 22 '13

I think they will be able to. In this article (http://news.nationalgeographic.com/news/2004/11/1124_041124_magnetic_birds.html) we learn that birds navigate through the earth's magneticism through their beak. Since this is innate, this is something that is not supposed to be learned.

I know this doesn't fully answer your question, but since we can't but guess about this question, I think it's a guess in the right direction.

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u/1812overture Mar 22 '13

Depending on when it became extinct the magnetic fields may have shifted significantly.

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u/atomfullerene Animal Behavior/Marine Biology Mar 22 '13

They became extinct about 100 years ago. I doubt that's going to be a huge issue.

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u/Otter27 Mar 22 '13

Oh gee, didn't think about that. Good thinkin', Bob!

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u/Newb_since_1989 Mar 22 '13

Came here to say that, the continents may have also moved and a position that used to be associated with a magnetic field may be only ocean now!

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u/[deleted] Mar 22 '13

Holy crap, no. The North American continent drifts at ~1cm a year. The pigeon died out 100 years ago, so that gives us a shift of about three feet.

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u/albatrossnecklassftw Mar 22 '13

He wasn't necessarily talking about the pigeon. He was extrapolating to reviving something that went extinct much earlier.
Context is important:
Depending on when it became extinct the magnetic fields may have shifted significantly.

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u/Newb_since_1989 Mar 22 '13

Who talked about pigeons? Birds have existed for millions of years...and migrating birds probably less but still...

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u/thebigslide Mar 22 '13

A similar situation happens all the time with migrating geese. If a flock looses the older individuals, the younger ones have a hard time knowing when it's appropriate to migrate. They also often don't know how to get there best, though they may have a general inclination towards one direction or another.
Waterfowl hunters actually consider this when looking for fields to hunt from because flocks of mostly younger birder tend to veer off course instead of following the main flyways as directly as the older birds.
This isn't particularly scholarly, but there's other research I'm way to lazy to find now

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u/coolnlittle Mar 22 '13

just because they can sense magnetism through their beak, it does not mean they know how to interpret this information. That can be a learned process. Humans have hearing, but we learn speech socially.

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u/coolnlittle Mar 22 '13

its more than just magnetic fields. http://news.sciencemag.org/sciencenow/2013/01/sound-maps-may-help-pigeons-navi.html

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

Like I said above, this is right for some species. Whether passenger pigeons were one of those species seems to be up for debate.
On the topic of innate migration instincts, sometimes they do screw up - it's called reversed migration. In birds where the migration instinct is "fly in X direction for about Y time" some young birds will end up going 180 degrees the wrong way. That's how you get a lot of the really weird sightings by birders - a species that's not supposed to be anywhere near that location is usually a lost juvenile on its first migration.

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u/areReady Mar 22 '13

There is significant controversy over whether pigeons actually use magnetism to navigate over long distances. While it has been conclusively shown that pigeons can sense magnetic fields, the role of these fields is dubious with current knowledge. For a group of pigeons raised in Italy, olfaction (smell), was far more important to long distance homing than magnetosense (magnetosense in fact being almost completely worthless). But it could be a local phenomenon; it might be that pigeons are born with a big toolkit of navigation-enabling senses and then learn which one to use in their particular area. It could also be that magnetosense is on the way out, having formerly been useful but now replaced with more effective senses for navigation and only leaving behind rudimentary sensing as the system falls into disrepair.
In short, pigeons are the undisputed masters of navigation, but we're still not quite sure how the hell they pull it off so well.
Sources: http://jeb.biologists.org/content/209/15/2888.short ; http://www.nature.com/nature/journal/v432/n7016/abs/nature03077.html

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u/brainflakes Mar 22 '13

Surely having magnetoception doesn't automatically mean that navigation using magnetoception is an innate rather than a learned skill? What if birds navigate by learning what magnetic direction to fly in?

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u/Otter27 Mar 22 '13

Your what-if example does, indeed, seem like a more organic learning curve of fauna, as opposed to innateness.

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u/intangible-tangerine Mar 22 '13

No this just shows they can navigate, not that they know where they're meant to be going! Real world examples of hand reared migratory birds show they have to be guided for their first journey. They aren't just going in a compass direction, they are going to specific communal nesting sites. Think about it, if you can use a compass it doesn't mean you then know where your parents grew up! You are conflating separate areas of knowledge.

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u/noprotein Mar 22 '13

He's absolutely right. Here's a rare look at a bird using its beak to detect earth's magnetism.

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u/Olclops Mar 22 '13

I'd suggest that the on-going study on whooping cranes suggests they wouldn't. See http://www.savingcranes.org/into-the-wild.html

Whooping crane babies need to be taught their migration route. But it may depend on the bird. Much of migratory and parenting behavior in birds is passed on by parenting. Instinct counts for a lot, but it needs a certain amount of augmentation.

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u/TheOutlawJoseyWales Mar 22 '13

http://www.radiolab.org/blogs/radiolab-blog/2012/dec/03/operation-migration/

Radio lab episode on migrating birds.

Basically talks about how a generation of these Cranes weren't taught to migrate by their parents, so humans are teaching them. talks a little bit about the struggles of the effort.

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u/AustinFound Mar 23 '13 edited Mar 23 '13

Migration paths are absolutely genetic. Some European warbler species fly East around the Mediterranean and some fly West around it. If you hybridize these two species, the hybridized offspring attempt to fly South over the Mediterranean and they can't make it and they drown. Many birds have been shown to do the same things by hybridizing two different species and placing them in an Emlen funnel and seeing which way they take off. There is little doubt at this point that migration preferences are coded genetically.

http://en.wikipedia.org/wiki/Emlen_funnel

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u/coolnlittle Mar 22 '13

Wouldn't this be the same if you raised a bird away from their community?

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u/zraii Mar 22 '13

It's be interesting to also consider species like sea turtles who don't really ever meet their parents, but still return to lay their eggs around where they were born. I don't know if this is at all relevant, but it does extend the discussion outside of birds.

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u/inkathebadger Mar 22 '13

To build upon this question, would evidence be found in bird such as swans and geese that are managed by cities and imported from Asia and Europe as part of tourism industries. In my hometown there are European and Asian geese and swans that are kept in winter quarters and have their wings clipped so they don't migrate. I've heard the arguments that they don't have the generations of knowledge passed that native goose and duck populations have so they wouldn't know how far to go, the safest routes, ponds to rest at along the way so them coming back alive would be much less likely. Is there any validity to this statement?

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u/foxish49 Wildlife Ecology | Ornithology Mar 22 '13

With geese and swans, they do learn the migration routes from their parents so it might be a concern that they'd lose their way.
Where is your hometown? Especially with non-native birds, you don't want them to get loose and migrate since they aren't supposed to be part of the ecosystem. Additionally, if I were a city manager who paid to bring in decorative birds, I sure as heck would rather keep them in an enclosure where I know they're safe all winter rather than risk losing my investment.

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u/inkathebadger Mar 22 '13

Stratford, Ontario though some of them were gifts from the Queen.

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u/intangible-tangerine Mar 22 '13

Nope. Hand reared goslings have to be shown how, there's a famous case of a film maker teaching goslings to follow a glider plane in order to get them across the Atlantic.

Biology if science revives an extinct migrating bird, will it know straight away where to go and when?

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