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Interesting comment from Daryl, it sort of described the mechanics,
indeed I have seen the behaviours modelled very nicely on a computer. I suspect
though, that the answer to Ray's question is what Martin sent. The habit of
flocks flying circuits is one of domesticated birds homing or learning the
environment around their lofts. Feral pigeons will do flocking behaviour but
generally not in coordinated groups flying in a circuit. In short, the
behaviour through Lyneham is likely not a
feral feature. I have always advocated against include counts of such birds in
the GBS.
Philip
This question was addressed in a very nice paper in
Nature a couple of years ago. (Nagy, M., Akos, Z., Biro, D., and Vicsek, T. (2010).
Hierarchical group dynamics in pigeon flocks. Nature 464: 890-893).
Apparently
there is a strict social hierarchy of leaders and followers within pigeon flocks
by which movement of the group is coordinated. Behavioural change by just a few individual
leaders is sufficient to initiate change in the whole group, allowing extremely
rapid collective manouvers to be made. The average spatial position of an individual within the
flock correlates with its place in the leader/ follower hierarchy,
birds higher in the
hierarchy are more influential in determining the direction of the flock’s
movement, and
changes in direction by leaders are copied by followers in a fraction of a
second. Presumably a similar mechanism operates in Starling, Budgeriagar,
etc flocks.
Daryl
On 18/08/2012 8:38 AM, Sue-Ellen and Ray
wrote:
Good morning all – An issue that has intrigued me for some time now is
the habit of these birds to congregate in large groups adopting a circular
(roughly) flight path within a relatively narrow bandwidth which continues for
what seems to be a long time. I have noted this occurs at about the same time
each day as I do my morning stroll through Lyneham.
Could anyone throw any light on this characteristic of the maligned feral
pigeon which now carries the much more respected name of Rock Dove.
Ray Comer
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