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Science

Sound From Bird Wings Act As a Predator Alarm 100

Posted by samzenpus
from the that-noise-means-something-terrible-for-you dept.
An anonymous reader writes "Biologists have discovered that a species of Australian pigeon has a secret way of alerting fellow birds to predators — a 'whistle' emitted by flapping wings when the bird takes off in alarm. The crested pigeon (Ocyphaps lophotes) is well known for the abrupt metallic-sounding whistle that it makes on takeoff. Many birds have the ability to make vocal cries to alert other members of their flock, but this is the first study to show that flight noise can also serve as an alarm call."
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Sound From Bird Wings Act As a Predator Alarm

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  • by QuantumG (50515) * <qg@biodome.org> on Thursday September 03, 2009 @01:47AM (#29295995) Homepage Journal

    I walk near birds minding my own business, they fly off and make racket doing so.. only once or twice have I yelled "WHAT!?" at them.. but people look at me funny.

    • Re: (Score:3, Interesting)

      by 4D6963 (933028)

      Actually, that reminds me, I grew up in France and I never could approach a bird within 20 feet without them flying away, until I visited England and the same kind of birds would approach as close as two feet from you as long as you didn't move too much. I never thought much of it until someone else made the same observation after visiting England.

      Now I don't see how the nationality of birds could possibly influence their behaviour towards people, but has anyone else even noticed this?

      • by lastgoodnickname (1438821) on Thursday September 03, 2009 @04:23AM (#29296809)
        french birds run away sooner?
      • Re: (Score:3, Insightful)

        by BrokenHalo (565198)
        Now I don't see how the nationality of birds could possibly influence their behaviour towards people, but has anyone else even noticed this?

        It might have something to do with the fact that (lots of) French people will kill and eat anything that moves. Evolution at work.
        • by 4D6963 (933028)
          Yeah, we assumed it might have to do with different behaviour from people, although it must be said that we're talking about very small birds, no one eats those.
          • Re: (Score:3, Informative)

            although it must be said that we're talking about very small birds, no one eats those.

            For reference, the Romans occasionally had hummingbirds on the menus at feasts. So people do (or did) eat very small birds.

      • Re: (Score:2, Informative)

        by hcpxvi (773888)

        In some parts of the continent ( mostly southern Europe: Italy and Malta for sure but France too) it is common for people to shoot small birds for the sheer fun of shooting them. Anything that flies is shot and they don't care if it is edible, or rare, or a protected species. See here [rspb.org.uk] for details.

        In the UK, shooting of birds is restricted to (a) Farmers shooting pest species (e.g. crows) and (b) rich people shooting specially-reared game birds (grouse, pheasant etc.) and (c) People with green wellies s

        • Re: (Score:3, Informative)

          by Canazza (1428553)

          There are paranoid pigeons in the UK too, there are also some hard bastards too.
          In Glasgow, Pigeons in and around Partick station are timid, paranoid and flee at the first sight of people
          a 5 minute walk away at the Botanic Gardens I've batted several pigeons out of the air for trying to nick my dinner.

      • Re: (Score:2, Interesting)

        by Ninja Pigeon (1630325)
        Hmmm. Interesting question. If you are talking urban birds, are English more likely to feed/drop crumbs then the French? Or perhaps it is the opposite, maybe there is less food around in England so the birds must act bolder in order to scavenge enough resources.
    • by 32771 (906153)

      Awesome! Teach those little buggers manners.

      I have to reply because I accidently modded you overrated and now I have to invalidate my mis-click.

  • Really? (Score:5, Funny)

    by acehole (174372) on Thursday September 03, 2009 @02:14AM (#29296125) Homepage

    I would have thought the 3 laser dots on your chest or the bodies hung upside down in trees would have been pretty good signs of a predator.

    • Re:Really? (Score:4, Interesting)

      by Supurcell (834022) on Thursday September 03, 2009 @06:22AM (#29297301)
      Remember when they found those skinless bodies in the tree in that movie and one of the guys said it was probably guerrillas who did it? Well, as a kid, I thought he was talking about gorillas. That is one scary-ass thing to learn about the gentle great apes in school, and then come home to see some fleshy corpses on TV that were killed by those same monsters.

      Then, last week, Planet Earth was on TV, and there was a gang of chimpanzees making war on a rival gang, then cannibalizing the bodies of their enemies! I am never going into the jungle.
      • by Supurcell (834022)
        Here [youtube.com] is a clip from that Planet Earth episode. Sometimes those chimps are behaving just too human for me, like at the end when one of them extends his arm and waits for another chimp to hand him a piece of chimp to eat. I do that all the time!
      • by Chris Burke (6130)

        Remember when they found those skinless bodies in the tree in that movie and one of the guys said it was probably guerrillas who did it? Well, as a kid, I thought he was talking about gorillas.

        Martin Short [imdb.com] made the same mistake when Kurt Russel told him to watch out for the guerrillas.

    • Ha. This post rocks.

  • by Mr. Roadkill (731328) on Thursday September 03, 2009 @02:16AM (#29296145)
    Twenty or twenty-five years ago I noticed that those little buggers made different noises when startled than when taking off normally. I thought that was something that everybody who knew the birds knew about. Guess I should have gone into biology, and taken a little more notice of what was quite literally in my own back yard when I was growing up.
  • I throw out my Budgie's bird seed regularly on the front lawn so we have a few of these hang out at our house quite a bit and they're beautiful little birds. The sound they make when they fly is quite distinct so you know if you've scared one off without even looking.

  • by Korbeau (913903)

    Sound Act As a Predator Alarm.

    News for ornithologists (and creepy old dudes with lens) - stuff that flies!

  • So a bird who's wings create a whistling sound in flight creates a different sound when it flees from a predator and that is interpreted as an alarm by other birds.

    It seems to me that the "alarm" is a side effect of "getting out of Dodge" and nothing more. The bird did not do anything different than any other fleeing bird when it created the noise. I did not do something special with its wings other than beat them harder and faster to get away faster

    The fact that other birds also react is a no brainer; "Gee

    • by Fluffeh (1273756)
      The interesting thing isn't that bids make a noise when they fly off, and that it's different to the noise when they fly off in a panic.

      The interesting thing is that OTHER BIRDS react to this noise and understand there is danger nearby.
      • by jklovanc (1603149)

        Sorry, still not "interesting". I bet if any noise was played at the same volume as the "alarm", different frequencies but same volume, that the birds would flee just as well. Birds fly from loud noises; any loud noises.

        Attributing something special to a bird's natural reaction to flee noise in suspect at best.

        • by Andvari (685645)
          The link in the article is short on details, however the recordings were played louder and the birds did not respond. (the full paper is available as a pre-print from proceedings B)
        • Re:Natural alarm. (Score:5, Informative)

          by Ninja Pigeon (1630325) on Thursday September 03, 2009 @05:28AM (#29297073)
          Mae here. Actually, we DID do exactly that to control for the possibility that they were simply responding to the louder noise. During playbacks we also played a series of neutral natural sounds (rosella bell calls) that we matched in amplitude to the volume of the alarmed whistle, the birds paid absolutely no attention to them. We also played whistles recorded under non-alarmed conditions at 'alarmed' volume, again the birds did not respond. They only responded to whistles recorded under alarmed conditions, played back at alarmed volume (and once or twice to whistles recorded under alarmed conditions but softened to the volume of non-alarmed whistles). Give us some credit, a lot of time and thought is put into experimental design. In answer to the previous note, indeed the 'alarm' is linked with 'getting out of dodge'. As such, we can not distinguish yet if the whistle is an intentional 'signal' or simply a 'cue', we state this in our paper. Possibly the sound is intended for another purpose (mate choice? species recognition?) and the fact that it also indicates alarm is a side effect. Irregardless of intended function from the perspective of the 'signaller', it still produces a different sound in alarmed flight and co-specific birds are still using it as an indication to flee, and benefiting from doing so. Another note, It is different from the wing noises of other birds in that the upbeat and downbeat produce very different tones resulting in a 'pulsed' sound during flapping. In other birds you just hear an indistinct 'whoosh' during flight, in Crested Pigeons the pulse enables you to hear the faster alarmed flap rate quite clearly. If all birds flew away every time they heard another bird fly (without knowing how alarmed that bird was) they would never get anything done! I expect many species deliver information through noisy take-off's in alarm, its just that the Crested has exaggerated it to communicate the degree of alarm more reliably, thus negating the need for additional vocal alarms. It is actually quite a neat system, it is more inherently honest/stable then standard vocal alarms in that there is a much higher price to 'faking' an alarm, as the bird MUST fly away, and hard, in order to produce an 'alarmed' type whistle. Thus eliminating any benefit it might have received through getting unlimited access to resources. In vocal alarm systems, there are practically no costs to producing false alarms. Additionally, the bird can't 'forget' to produce the sound, the whistle is inherently graded and it also does not take any extra effort to produce. Additionally, since it causes all the other birds to also flee, it offers a benefit to alarm signalling, the escape of the individual who first flies away will be 'hidden' in the flights of others and the huge noise produced by the escaping flock is also likely to double as a way to scare/distract the predator. All at no extra cost, given the bird would be escaping anyway. Anyway, sorry you didn't find it interesting, each to their own. I know i loved working on it, and i think they are fantastic little birds, lots of character :) p.s. Sorry for the super long post. Ooops! Overenthusiasm.
          • wow. sorry guys. I originally had paragraphs in there. Not sure what happened o_O
            • /. ate them. You were probably posting in HTML mode instead of test mode.

            • Thanks for responding in slashdot. Not many original authors show this much enthu. After all most slashdotters are not qualified in experimental biology and we are prone to comment without reading either the article or the summary. So many authors, quite reasonably, dismiss slashdot criticisms as fluff. Thanks for setting the record stragitht.

              .

              Irregardless is not a proper word. Regardless is what you mean from the context. The prefix Irr is usually negative (example: regular, irregular). If irregar

          • Re: (Score:3, Insightful)

            by Chris Burke (6130)

            In vocal alarm systems, there are practically no costs to producing false alarms.

            And a possibility for great reward, as the Blue Jays know well. Bastards love to alarm call right as they're swooping in to the bird feeder.

            Anyway, sorry you didn't find it interesting, each to their own.

            Yeah, I wouldn't put much stock in the fact that a guy who knows literally nothing about the subject other than what they read in the summary, and is trying to use that vast body of knowledge to prove that they are smarter th

          • by LanMan04 (790429)

            Thanks for the post. Very interesting stuff.

      • by techess (1322623)

        I think the other thing that is interested is that it isn't just "other birds". I have horses and I've always noticed that when a flock of birds take off normally that the horses won't even lift their heads from grazing. When the birds take off in a panic the horses heads come up and they scan looking for the predator and sometimes begin defensive measures (spooking or bolting).

        When you spend a lot of time riding in fields on a spooky horse you get trained to the sound as well. Birds in a flock moving ar

        • Re: (Score:2, Informative)

          by Ninja Pigeon (1630325)

          This is interesting! There is a lot of evidence that different bird species can recognize the alarm noises/actions of other bird species (with similar predators), and some stuff on monkeys recognizing bird alarms as well. I haven't heard of horses spooking to spooking bird flocks before. I wonder if the horse is spooking to the louder sound of a spooked flock, or if it understands that the birds have seen a threat. I guess it would depend what the birds were most often spooking from, if the birds usually sp

          • by techess (1322623)

            The horse that is worst for spooking at danger signs (the alpha horse) is also the only one that could probably survive on his own. Most of the others wouldn't last the winter. I have one that used to winter in Flordia before I got him an he still hasn't learned that you can't drink ice and he bangs his face into frozen puddles when he wants to drink.

  • by Anonymous Coward

    From http://www.gardenbird.co.uk/Wood-Pigeon-Information/Bird-Watching/GBS_birdType_WoodPigeon,default,pg.html

    Sometimes they can be seen feeding on nut bags but because of their large size they generally forage on the ground and if they are disturbed when feeding they clap their wings to scare off other birds.

  • Did the researchers employ Robert Frost shaped balloon sculptures in this study?

  • I have mourning doves nestling on my balcony, their wings also whistle, but it seems like every time they take off, and not only when they're alarmed.

    • Re: (Score:2, Funny)

      by BrokenHalo (565198)
      Do mourning doves' wings whistle dirges?
    • Re: (Score:2, Informative)

      by Ninja Pigeon (1630325)
      A similar study has actually been done on mourning doves. Crested pigeons also always whistle in flight (both non-alarmed and alarmed), its just that when alarmed the whistle sounds more rapidly pulsed and louder then it does when the bird is not alarmed.
  • I know the one... (Score:5, Interesting)

    by MrKaos (858439) on Thursday September 03, 2009 @03:07AM (#29296409) Journal

    the abrupt metallic-sounding whistle that it makes on takeoff...

    That scares the absolute crap out of you if you haven't noticed them while you are going out to hang the washing on the line. Just another one of the craaazzzyy animals that occupy my back yard.

    Possums that fall out of trees when *you're* drunk, and then look all embarrassed about it - waaay too funny - I mean they live in trees.

    Myopic Kookaburras that *miss the ground* when hunting for food and slide along in a cloud of dust and feathers, get up and look at you like 'oh it's just a human'.

    The obstreperous lorikeets that race each other (they get to about 60kph) and decide both sides of your head is part of the obstacle course they are flying, squawking loudly as they pass by, also scaring the crap out of you.

    Or the owls that sit on the washing line at night and wait until you are about a foot away from them before they fly off and *also* scare the crap out of you.

    Oh yeah, Australian animals are all mental.

    • That's right. And don't forget the drop-bears that hang from lamp-posts at night and drop on you if you haven't taken the precaution of rubbing Vegemite behind your ears.

      ;-D
      • by MrKaos (858439)

        That's right. And don't forget the drop-bears that hang from lamp-posts at night and drop on you if you haven't taken the precaution of rubbing Vegemite behind your ears.

        That's just cruel. Locals know that dropbears *love* vegemite as much as the ears that it is smeared on. YOU shouldn't be telling people such fabrications or else tourists might get hurt trying to stop them. A bit of responsibility, please.

    • Don't forget the Dropbears. One of those buggers nearly took my head off last ANZAC Day while I was driving my ute down to pick up some prawns for the barbie.
      • by MrKaos (858439)

        Don't forget the Dropbears. One of those buggers nearly took my head off last ANZAC Day while I was driving my ute down to pick up some prawns for the barbie.

        One nearly took a roo steak I had on the barbie right off the barbie, the cheek of the thing. Fortunately I was on the last swig of me pale so I threw the bottle at the friggin thing. I dunno what it's like around your way but the drop bears here have been gettin *real* aggressive.

        They can hurt ya, but maybe you can eat them?

    • *sings!*
      Red Backed, Red Bellied, Blue Ringed Octopus
      Tiapan, Tiger Snake, Death Adder, Box Jellyfish
      *Shark!!*

      Come to Australia..... You might accidentally get killed!

  • Similar studies have been done with Mourning Doves [springerlink.com] (free abstract) and they have the same effect.

    • Re: (Score:2, Informative)

      by Ninja Pigeon (1630325)
      Yeah, i think its actually quite widespread. The mourning dove paper didn't manage to get them to flee, but i think that is because i think they amplitude matched alarm and non-alarm volumes. My birds did not flee either when the amplitude of the alarms was not natural, they were still more vigilant though. I think if they redid their work taking into account the volume aspect they would have got the exact same result.
  • I've always wondered why pigeons fly so loudly. It costs energy to make sound, so it can't be efficient.

    It all makes sense now.

    • by LSD-OBS (183415)

      You can definitely hear the difference when a pigeon takes off due to being startled, and when it launches itself normally. I always considered the nosie to be from coming from its wings, and as a signal conveying danger. Somehow this news seems like it isn't.

      • Indeed. The theory was all based in common sense. But so is much science. We are not claiming it is 'new' information per se, we are just providing evidence that a long held assumption was correct. Just because a difference in sound exists does not then prove that the birds actually use it in communication, this study did. We are not claiming to be geniuses for 'figuring it out' and know that lots of other people would have come to the same idea independently, we just wanted to test it. I think there is mer

        • by LSD-OBS (183415)

          Oh, believe me, of course I understand what science is, and I'm all for the independant and stringent validation of assumptions and even common knowledge. The point is, it's not really news, especially not on slashdot, is it?

          • I didn't mean to imply you didn't, sorry :(
            As for news, I guess that depends on what you define as news. It's not 'people' news obviously, but some news is just about learning a bit about the natural world around you, more of gaining knowledge for the sake of knowledge. I understand if you don't think it is appropriate for slashdot though, i don't really know what is appropriate here myself (i'm new, someone just emailed me that it was being discussed here) but i didn't actually post it here. You are welcom

  • Acts... (Score:2, Informative)

    by MarkoNo5 (139955)
    Sound from bird wings acts .... Sounds act, sound acts, mr. samzenpus.
  • They don't differentiate between big squarish, four-wheeled predators and the more flappery kind.
  • We have a lot of turtledoves [wikipedia.org] around here and they make a very loud whistling sound when they take off abruptly, usually causing every small critter (birds, squirrels, etc) in the area to scramble. Nothing new here?

  • I found some linked from this writeup [sciencemag.org]. It's a neat sound, one I'm tempted to sample and throw into music, but then again I say that after hearing almost anything.

  • That most bird species make a different sound on a alarmed take off.

    Most of them just beat their wings harder than normal to make a thumping sound to alert other birds to the possibility of danger.

Whenever a system becomes completely defined, some damn fool discovers something which either abolishes the system or expands it beyond recognition.

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