Birds in V formations are frequently observed and two main hypotheses have emerged to explain this particular geometry: (i) it offers aerodynamic advantages and (ii) it is used to improve visual communication. Both explanations require a bird to track its predecessor. However, most V-formations observed in nature are small and the distribution of wing-tip spacings has a large variation. This suggests that tracking the lateral position of the preceding bird is a difficult task. Control theorists, when trying to control platoons of vehicles, also noted that predecessor following is difficult. In this paper, we apply a result from systems theory to explain the observations of bird V-formations. The strength of this result is that it does not rely on the details of the bird flight model. Thus we claim that formation flight is inherently difficult for birds.
Bibliographical noteFunding Information:
$This work was supported in part by Office of Naval Research (ONR) under the grant N00014-99-10756. nCorresponding author. Tel.: +1-510-642-6933. E-mail addresses: pseiler@vehic le.me.berkeley.edu (P. Seiler), email@example.com (A. Pant), khedrick@vehicle. me.berkeley.edu (J.K. Hedric k).