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Roadkill Forcing Cliff Swallows To Evolve 387

Posted by Unknown Lamer
from the also-evolved-laser-eyes dept.
sciencehabit writes "Cliff swallows that build nests that dangle precariously from highway overpasses have a lower chance of becoming roadkill than in years past thanks to a shorter wingspan that lets them dodge oncoming traffic. That's the conclusion of a new study based on 3 decades of data collected on one population of the birds. The results suggest that shorter wingspan has been selected for over this time period because of the evolutionary pressure put on the population by cars."
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Roadkill Forcing Cliff Swallows To Evolve

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  • Tricky EIRs (Score:3, Interesting)

    by Anonymous Coward on Monday March 18, 2013 @10:11PM (#43210133)

    This could be tricky, if this gets classified as a new species, how do we factor in the need for persistant traffic in environmental impact reports? If we cut traffic this species would lose its competitive edge and thus habitat and could become extinct!

    • Quick! Before it becomes a new established species, if you see one swerve your car dangerously to try and hit it!

    • Re:Tricky EIRs (Score:4, Informative)

      by Luckyo (1726890) on Monday March 18, 2013 @11:00PM (#43210391)

      No. The change is likely morphological rather then genealogical. As a result they will stay the same species, just like dogs do.

      • If you take a population of poodles, and breed them selectively for long enough, they would become a separate species. It just hasn't gotten that far yet.
        These swallows can just mix with the general population too, but given enough time, would become a separate species.

        • by dywolf (2673597)

          That's only because they keep breeding poodles to be poodles. They arent selectively breeding them to change them into something new.
          If it was me, I'd be going for size....big,,,curly haired...attack poodles!

      • >> No. The change is likely morphological rather then genealogical. As a result they will stay the same species, just like dogs do.

        And what if hedgehogs 'evolve' tungsten-carbide spikes that make car tires deflate so that they are fighting back the cars that kill them, and the car makers fit all their cars with caterpillar tracks... Would you consider those cars 'merely morphological' or genealogical different?
        And what about flying cars, is /that/ a new breed to you?
      • That is the same thing. They would still become different species after their outward appearance changed sufficiently, just like dog breeds.

        A 180-pound English Mastiff and a two-pound Chihuahua, are not the same species, by any definition of the term.

        • A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The species is the principal natural taxonomic unit, ranking below a genus and denoted by a Latin binomial, e.g., Homo sapiens

          If the sperm from one can create fertile offspring in the other, it's the same species...

          • First off that is not the definition of a species.

            And even using that definition, the would not be considered a species.

            We all use DNA, so it would not be difficult to interbreed any two species on the planet together. How a species puts together its sperm and eggs prevents most species from interbreeding, but that is a tiny part of an organism and not particularly important when defining species.

            Let us assume that even if you could impregnate a female Mastiff with with Chihuahua sperm that she came to term

    • Re: (Score:3, Insightful)

      by NFN_NLN (633283)

      This could be tricky, if this gets classified as a new species, how do we factor in the need for persistant traffic in environmental impact reports? If we cut traffic this species would lose its competitive edge and thus habitat and could become extinct!

      Unlike religion, taxonomy is based on science. You can't just name something a new species because of a slight variation.

      Species:
      A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

      If the short wing swallows can breed with the long wing swallows to create fertile offspring... they probably aren't a new species.

      • A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

        You make it sound so easy, when it is not, and the GP has a point.

        It's easy to tell when two things aren't the same species in many cases: e.g. a grey parrot and a rainbow trout.

        But in many cases it's very much harder. Evoloution isn't a neat tree with branches handily cut off as species (or clades). It's a DAG which at coarse scales rather resembles a tree. The arrows point in the direction of time si

      • by Lotana (842533)

        Species definition is quite messy. Easiest example is Tiger and Lion; They are listed as members of two separate species, yet they can interbreed.

    • ...environmental impact reports?

      Don't be a smartass...

  • excellent! (Score:5, Funny)

    by arekin (2605525) on Monday March 18, 2013 @10:11PM (#43210135)
    Now if only humans would evolve that fast...
    • by Grayhand (2610049)

      Now if only humans would evolve that fast...

      We have. Our asses have spread to better secure ourselves to couches. Our bellies are also evolving into shelves for beer cans.

    • by skine (1524819)

      If creating roadkill is the cause, then I've been doing part for years!

  • by NEDHead (1651195) on Monday March 18, 2013 @10:11PM (#43210137)

    If I keep on smacking my kids, their arms will get shorter?

  • by Anonymous Coward on Monday March 18, 2013 @10:12PM (#43210141)

    ...And this is yet another proof that God exists. My prayer circle has spent the last 10 years asking for Divine intervention to halt the senseless deaths of road-adjacent animals. Thanks to our unceasing intervention, He knew to trim a wee bit off the tip of every bird's wings (gradually, of course, so that mommy birds would still recognize their babies - and left longer wings on the sinner birds so that they would die and serve as a warning to others). Praise Jesus!

    • Re: (Score:3, Funny)

      by Anonymous Coward

      That is a really tough story to... Swallow...

  • by spongman (182339) on Monday March 18, 2013 @10:12PM (#43210143)

    these evolutionists are just trying to force these lies down your throats.

    how can the birds be changed by the overpasses? the bible tells us that the overpasses have existed since the creation of the universe, 3 decades ago.

    • by Trepidity (597)

      This is clearly heresy. As is recorded in the bible quite clearly, overpasses do not exist, and have never existed.

    • Re:lies, all lies (Score:5, Insightful)

      by Anubis IV (1279820) on Monday March 18, 2013 @10:30PM (#43210237)

      The funny thing, at least to me as a Christian, is that none of the other Christians I know would take issue with anything said in the summary, other than the use of "evolution" to describe natural selection and adaptation: principles with which they have no problems.

      • Re:lies, all lies (Score:4, Insightful)

        by X0563511 (793323) on Monday March 18, 2013 @10:48PM (#43210335) Homepage Journal

        ... even though that's exactly what evolution is?

        I think they have a hard time understanding what the Theory of Evolution really is. If they did, they'd suddenly find it's compatible with faith as-is.

        • Re:lies, all lies (Score:5, Interesting)

          by LordLucless (582312) on Tuesday March 19, 2013 @12:07AM (#43210693)

          Evolution and abiogenesis are frequently conflated. Many Christians have no problem with the former, but do not agree with the latter.

          • They do not agree that at some point life appeared where there was none before via some process---which is hte definiion of abiogenesis.

            That's an odd thing to believe.

            • No. Abiogenesis is life arising from non-living matter. In context as a piece of scientific terminology, it also usually conotes a natural process (i.e. not divine intervention).

              Merriam-Webster [merriam-webster.com]
              Wikipedia [wikipedia.org]

        • Re:lies, all lies (Score:5, Insightful)

          by Anubis IV (1279820) on Tuesday March 19, 2013 @02:41AM (#43211243)

          Hmm...yes and no. When people talk about "evolution", they're generally talking about the creation of new species via the combined mechanics of random mutation and natural selection. Natural selection is something that everyone I know is fine with. Random mutation is something that everyone I know is fine with. But the creation of new species? Not so much. And in this case, we're merely seeing natural selection at play, which is not evolution, in and of itself, any more than a motor by itself should be considered a car.

          • by drinkypoo (153816)

            But the creation of new species? Not so much.

            All "new species" means is "genetically incompatible". When people talk about evolution, they'd better fucking know what species means.

            And in this case, we're merely seeing natural selection at play, which is not evolution

            Uh wrong. If the changes we're seeing are genetic, then we're seeing evolution at play, through the mechanism of more or less natural selection. Consult your dictionary, it can help you the way it has helped so many others not be blatantly, stupidly wrong.

          • by Creedo (548980)

            Natural selection is something that everyone I know is fine with. Random mutation is something that everyone I know is fine with. But the creation of new species? Not so much. And in this case, we're merely seeing natural selection at play, which is not evolution, in and of itself, any more than a motor by itself should be considered a car.

            Until the sub-species is altered in some way to prevent interbreeding(physical isolation, physical inability to mate, behavioral changes which prevent mating, etc), it is indeed not a speciation event. It is, however, evolution("a change in heritable traits over time"). The term "species" is just a convienent label to place on living things in order to categorize them. It is just a snapshot of a particular group of living things at a particular time. All species are always adapting, always evolving. Some ca

      • The funny thing, at least to me as a Christian, is that none of the other Christians I know would take issue with anything said in the summary, other than the use of "evolution" to describe natural selection and adaptation: principles with which they have no problems.

        Dude, I gotta ask, how can you be on the internet and not have seen them?

        • I'm not denying that they exist, merely that they're representative of the whole. I'm aware that they're out there. I just don't know any personally, despite having grown up in the church. In fact, I learned about those principles while attending a private Christian school, back almost 20 years ago now (and no, I didn't learn them as "these are evil ideas that Godless people will try to tell you are truth", despite the stereotypes and Internet crazies that might lead you to believe otherwise :P).

      • Yes well , evolution is just a nice way of saying that all the birds with too long wings that chose to nest at an overpass, got splattered by traffic...
  • by Anonymous Coward on Monday March 18, 2013 @10:12PM (#43210145)

    What is the new air speed velocity of an unladen cliff swallow?

  • by Leuf (918654) on Monday March 18, 2013 @10:20PM (#43210181)
    The article says it's because they are more maneuverable, but what if they just sit on their asses a lot unlike their easier flying longer winged relatives? Fly less, get hit less.
    • Fly less, get less food, starve to death?

      • by Leuf (918654)
        Fly with a purpose when needed, live. Play dodge the highway traffic because you can, splat. If it takes more effort to fly then maybe you cut down on your recreational flying. Sort of like higher gas prices.
    • by Solandri (704621)
      Yeah, the maneuverability part was supposition (it's not like they tested the birds with shorter wingspans to see how much more maneuverable they were).

      Here's an alternative possible explanation. Older birds are bigger. Older birds have slower reactions. As overpasses became more common, it was predominantly older birds which were killed disproportionately by passing cars. Consequently the birds may have increased in number, but their population distribution is now skewed towards the younger, smaller
  • by Greyfox (87712) on Monday March 18, 2013 @10:51PM (#43210345) Homepage Journal
    I was driving up in the mountains a year or so ago and saw a chipmunk run out into the road between me and the car coming the other way. Now normally this is pretty much certain doom for the chipmunk, but this one stopped calmly on the yellow line, stood up and waited for us to pass before continuing. I've always wondered if the evolutionary pressure of traffic combined with their short generation cycles would lead to critters less likely to become roadkill. Guess I have my answer.
    • by KC1P (907742)

      I'm wondering the same thing about moths. In the last few years I've really started noticing that when I'm driving my car at night on a quiet road with no traffic, moths that are fluttering over the lane will suddenly drop to the pavement as my headlights hit them.

      Sort of like a fainting goat, only more useful -- moths who have mini-seizures when they see headlights must have a higher survival rate because now all they have to worry about (besides being bashed up a bit by the fall) is my tires, which are a

    • by TheLink (130905)
      Similar here I was wondering how long it would take for dogs, cats, etc to evolve to wait for traffic to pass before crossing.

      I see hawks or eagles circling some highways nowadays - I wonder if roadkill makes up a significant part of their diet. But they'd better learn to avoid becoming roadkill too ;).

      On a related note, I wonder if we are doing the wrong thing by eating/killing the larger members of various fish species while leaving the smaller ones alive. Seems to me for millions of years its been the sm
      • re: I see hawks or eagles circling some highways nowadays
        :>)
        My understanding of why birds of prey are often seen circling highways is that they are taking advantage of thermals [wikipedia.org], rising columns of air heated by the asphalt/cement roadway surfaces, to power and maintain their gliding and flying. The fact that there's also an abundance of roadkill may have something to do with it also. See also http://en.wikipedia.org/wiki/Wedge-tailed_Eagle#Behaviour_and_diet [wikipedia.org] for how the eagles can observe thermals wi
      • by sjames (1099)

        Crows in Japan have made the most of it. They drop nuts into an intersection, wait for the walk signal and then pick out the meat after car tires do the hard work for them. When the sign changes to don't walk, they fly back up to a wire and wait.

        • They drop nuts into an intersection... and then pick out the meat

          They can keep away from my meaty nuts, I says.

      • I think smarter dogs, who check for oncoming vehicles before venturing onto a road, will survive more. You can notice this behaviour in a few dogs in places that have large numbers of strays.

        It would be interesting to note how quickly this could result into an increase in the average intelligence of dogs (heh heh). Of course, not all dogs live near highways. This roadkill risk has arisen only in the last 100 years.

        • by TheLink (130905)

          You can notice this behaviour in a few dogs in places that have large numbers of strays.

          The males seem to lose their traffic sense once a female in heat is in sight.

          But that happens to humans too ;).

      • You are aware that the size difference in fish is NOT to seperate fit from unfit fish but that is a seperation on AGE of the fish?

        Basically you are suggesting that the answer to a healthy fish stock for the future is to kill all the young and life the adults to swim free...

        I know this is Slashdot and that with your intelligence we should all be grateful you got so little practical experience with reproduction but I think that even you might need to read up a bit on how a species survives.

        Hint: It involve

    • by DigiShaman (671371) on Monday March 18, 2013 @11:43PM (#43210597) Homepage

      Squirrels. They used to zig-zag back and forth (can't make up their mind) and get crushed. Now, they either wait patiently or bolt across the road when everything looked all in the clear.

      But yes, it would seem the indecisive critters got weeded out.

    • by Grayhand (2610049)

      I was driving up in the mountains a year or so ago and saw a chipmunk run out into the road between me and the car coming the other way. Now normally this is pretty much certain doom for the chipmunk, but this one stopped calmly on the yellow line, stood up and waited for us to pass before continuing. I've always wondered if the evolutionary pressure of traffic combined with their short generation cycles would lead to critters less likely to become roadkill. Guess I have my answer.

      I wish deer would learn this trick. I had a pair of them stop and stare at my car. Unfortunately they chose a night when the road was like glass and my brakes were nearly useless. I finally managed to change lanes a few feet from them and they only moved after my car was even with them. If I hadn't grown up driving on ice I would have had a face full of air bag and two deers riding shotgun. Apparently Chipmunk behavior is evolving faster than deer behavior.

    • My mother had a funny encounter with a hare when she was young. She was driving on a small country road at night, and suddenly a hare jumped from the field onto the road between her headlights. Not knowing how to dress one anyways, she slowed down.

      What happened then was hilarious. The hare saw the left head light, became scared and jumped to the right. Being now closer to the right head light, it became scared again and jumped to the left. Then again to the right, and so the hare became trapped between her

      • Venison is deer, you could possibly call the meat game, if you're looking for a generalized name for roadkill meat.

  • by camperdave (969942) on Monday March 18, 2013 @11:06PM (#43210413) Journal
    Yes, this may be due to evolution, not of the birds, but the automobile.

    To generate increased fuel economy, today's automobile is a lot more streamlined than ones of the past. So there is less air disturbance. It may be that the birds with smaller wings are not affected by the turbulence as much as the larger winged birds are now, and can thus survive an encounter, whereas in the past, there was enough turbulence to affect the birds regardless of wingspan. Also, changes in traffic patterns and vehicle types changes the exhaust, which changes the local plant life, which changes the insect life, which ultimately changes the birds.

    While it is simple to observe that long winged birds are being disproportionately killed and that the population's wingspan is growing shorter, and conclude that some sort of selection (Is it natural selection when birds are hit by cars?) is taking place, the reality may be quite different.
    • by Vreejack (68778) on Tuesday March 19, 2013 @12:45AM (#43210853)

      Um, what? Are you trying to suggest that bird wings are shrinking because automobiles produce less turbulence than they used to?

      I have seen some really stupid write-ups in Science, but this one was concise and accurate. Roadkill birds have longer wings and the average wingspan has decreased over the decades of the study. It is known that birds with shorter wingspans are more agile in the air. The conclusion is that roadkills are placing a selection pressure on the birds for shorter wingspans. Turbulence is not actually believed to play much of a part, as death is caused when the birds are struck by cars, not when they get caught in their wake.

      • maybe, caught in their wake, and then struck by the next car? (which they might have been able to avoid if they weren't caught in turbulence)?
      • by camperdave (969942) on Tuesday March 19, 2013 @10:08AM (#43212833) Journal

        Um, what? Are you trying to suggest that bird wings are shrinking because automobiles produce less turbulence than they used to?

        No, I am suggesting that bird wings are shrinking because the automobiles are using a different blend of fuel than they used to.

        Further, I am suggesting that turbulence inducing vehicles might be harder to avoid. The wake could cause a bird to hit the side or rear of a vehicle, or whip it into the ground, or just be violent enough to snap the wing altogether without the bird even hitting anything. Who knows? If the types and sizes of vehicles, the frequency and distribution of traffic, and even the fuel composition of the vehicles travelling through the underpass were the same, then the conclusion would have been a slam-dunk. However, the traffic now is not the same as it was thirty years ago, so there is another variable in the scenario; a variable that could cause the same observed phenomenon (unlikely though it may be).

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Is it natural selection when birds are hit by cars?

      Why would it not be natural selection?
      The environment in which the birds exist was rapidly changed due to the actions of another migratory species.
      This new environment is more dangerous to birds with a larger wing span. The birds with dominant short wing span alleles were able to survive longer and produce more offspring. Ergo, the nature of the environment selectively breed for short wing span alleles in this species in bird. The fact that the environmental change that catalyzed this selective process was

  • Kinda Related... (Score:5, Interesting)

    by SuperCharlie (1068072) on Tuesday March 19, 2013 @12:12AM (#43210719)
    I had to go through a set of lights by a couple truck stops back in the day more than once a week. I noticed grackles (crowish kinda birds) that would wait on the posts or nearby for the lights to turn red. Then they would jump down and pick the grasshoppers and bugs out of the 18 wheeler grills. When the light turned green, they all flew back up and waited. They were quite well fed.
  • What effect does this have on their air speed and coconut carrying ability?

    • They'll just land on a truck with their coconut, and ride along. Much less tiring this way, and faster too...
  • by flimflammer (956759) on Tuesday March 19, 2013 @03:11AM (#43211329)

    Is that seriously enough time for such an evolution to take place? I was not aware evolution happened so quickly, even accounting for their quicker viability for reproduction. Seems like there might be a million other reasons why this is happening, not because of something so recent.

    • Is that seriously enough time for such an evolution to take place? Seems like there might be a million other reasons why this is happening, not because of something so recent.

      It happened recently, so yeah, it probably is due to something recent. Don't believe it? You can always get yourself a PhD like the scientists who did the study and repeat the research yourself.

      Evolution can easily occur in a single generation if the selection pressure is high enough. In fact, it does occur, all the time, in every generation, but just isn't always this noticeable.

  • ... to simply avoid building nests that dangle precariously from highway overpasses? Why not chose safer nesting places? What if a huge truck passes on top of the bridge, shaking it so much that the nest comes off and falls down on the highway below? Then the brood is dead, shorter wingspans or not...
  • We often get stories like this where some scientists make some observation and declare that that was due to evolution. If evolution is such a great theory, how about someone come up with a prediction for once, as in something like, "Due to these conditions, this so-and-so life form will eventually evolve to have such-and-such appurtenances with such-and-such characteristics". Anybody up for the challenge?
    • how about someone come up with a prediction for once, as in something like, "Due to these conditions, this so-and-so life form will eventually evolve to have such-and-such appurtenances with such-and-such characteristics". Anybody up for the challenge?

      How about Darwin himself predicting that ther must be some mechanism for passing on most of the characteristics of parents on to children but with the opportunity for relatively small random changes to happen: small enough to be not necessarily harmful.

      DNA cro

      • by petman (619526)
        That's not a prediction. That's a proposition. Prediction is about estimating a future event. DNA already existed at the time, it's just that Darwin didn't know about it. So Darwin made a proposition, not a prediction.

I'd rather just believe that it's done by little elves running around.

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