Editing Flocking (section)

=== Measurement ===
Measurements of bird flocking have been made<ref>{{ cite journal | last =Feder | first =Toni |date=October 2007 | title =Statistical physics is for the birds | journal = Physics Today| volume =60 | issue =10 | pages =28–30 | doi =10.1063/1.2800090 | doi-access =free | bibcode = 2007PhT....60j..28F }}</ref> using high-speed cameras, and a computer analysis has been made to test the simple rules of flocking mentioned below. It is found that they generally hold true in the case of bird flocking, but the long range attraction rule (cohesion) applies to the nearest 5–10 neighbors of the flocking bird and is independent of the distance of these neighbors from the bird. In addition, there is an [[anisotropy]] with regard to this cohesive tendency, with more cohesion being exhibited towards neighbors to the sides of the bird, rather than in front or behind. This is likely due to the field of vision of the flying bird being directed to the sides rather than directly forward or backward.

Another recent study is based on an analysis of high speed camera footage of flocks above Rome, and uses a computer model assuming minimal behavioural rules.<ref>{{cite journal | last1 = Hildenbrandt | first1 = H | last2 = Carere | first2 = C | last3 = Hemelrijk | first3 = CK | year = 2010 | title = Self-organized aerial displays of thousands of starlings: a model | journal = Behavioral Ecology | volume = 21 | issue = 6| pages = 1349–1359 | doi = 10.1093/beheco/arq149 | doi-access = free | arxiv = 0908.2677 }}</ref><ref>{{cite journal | last1 = Hemelrijk | first1 = CK | last2 = Hildenbrandt | first2 = H | year = 2011 | title = Some causes of the variable shape of flocks of birds | journal = PLOS ONE | volume = 6 | issue = 8| page = e22479 | doi = 10.1371/journal.pone.0022479 | pmid=21829627 | pmc=3150374| bibcode = 2011PLoSO...622479H | doi-access = free }}</ref><ref>[http://www.rug.nl/sciencelinx/exhibits/swarming/index Project Starflag]</ref><ref>[http://www.rug.nl/fmns-research/beso/_people/hemelrijk Swarm behaviour model by University of Groningen]</ref>