Alas, fundamental principles in animal behavior still tell us that animals should act selfishly. For selection to favor weakest individual willing to be in the hardest position, it only has to be the case that being in the hardest position in a group is still better than being alone. The reason we would expect the strongest individuals to be in the easiest positions is because they can move the weak individuals over. Selection should favor strong individuals who do not use their when they don't have to.
The only conditions under which this arrangement should be violated is when the strongest individual gains a benefit from the weaker individual's presence. Only if this last condition is satisfied could selection favor strong individual willing to do the hardest job. Of course, if fighting is costly, this must be taken into account. Eric On Mon, Mar 7, 2011 10:00 PM, "Hugh Trenchard" <[email protected]> wrote: > > > >>I'm curious to know if there is much >work showing the relative strengths of the birds and their proportionate >times spent in various positions. For example, intuitively one might >expect that weaker birds would actually take the easiest positions for longer >durations (contrary to the ornithologist's assumptions of the day); >conversely one might expect the weakest birds to be in the most difficult >positions for shorter durations than the stronger birds. I >imagine the rotational pattern to be counter-intuitive, at least >counter-intuitive to my understanding of peloton dynamics, since a weak >bird in a hard position can't simply accelerate to the easiest position at the >apex - unlike a weakening cyclist in the hardest position at the front, who can >simply decelerate and find a drafting position behind. >> > >>From this one might imagine that flock >rotation is more of a "backwards rotation" in which new effective apex >positions are created farther back in the flock. These might be initiated >by weaker birds behind the apex position, which due to weakening, gradually drop >backward at some angle (perhaps) to its previous trajectory, and >creates a new apex position for another bird (but not for the bird >that started drifting back). One might imagine events in which >such a drift backwards is lateral across to the opposite arm of the vee in >order to avoid wing collision and/or some sort of other air >instability. This might also create new or effective apex positions where a >weaker bird may be able to recuperate. These adjustments behind the >apex would also, one might imagine, force the bird in the previous apex position >also to readjust position when the imbalance in uplift on either side begins to >weaken it (if that happens). >> > >>In any event, I'm just throwing out some thoughts >here and I would be interested to know if there is much work on flock >rotational dynamics (I haven't seen much, but I haven't done an exhaustive >search). >> > >> > >>Hugh Trenchard >> > >>----- Original Message ----- > > > >From: > <a title="" href="#">[email protected]</a> > > >To: <a title="" href="#">[email protected]</a> > > >Sent: Monday, March 07, 2011 12:59 > PM > > >Subject: [FRIAM] Birdies do the right > thing! > > > > > >Yes, as > always, Steve is correct. In my 1971 paper I included some > stability calculations indicating that for a flyer moving ahead of the Vee > line things became tougher, and vice versa. >The funny thing, as noted in > that paper, was that the lead bird, at the apex of the Vee, had the easiest > job. This caused a lotta comment by ornithologists who had observed that > the lead position was normally assumed by the oldest and senior bird. > They asked, "Why would the strongest take the easiest job?". > My cynical answer was, "Twas ever thus, for Birds and Men!" >Peter Lissaman, > Da Vinci Ventures > >Expertise is not knowing everything, but knowing what > to look for. > >1454 Miracerros Loop South, Santa Fe, New Mexico > 87505,USA >tel:(505)983-7728 > > > > > > > > > > > ============================================================ >FRIAM > Applied Complexity Group listserv >Meets Fridays 9a-11:30 at cafe at St. > John's College >lectures, archives, unsubscribe, maps at >http://www.friam.org ============================================================ >FRIAM Applied Complexity Group listserv >Meets Fridays 9a-11:30 at cafe at St. John's College >lectures, archives, unsubscribe, maps at http://www.friam.org > Eric Charles Professional Student and Assistant Professor of Psychology Penn State University Altoona, PA 16601
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
