title: Goal-dependent current compensation and drift in surf scoter flocks.
abstract: BACKGROUND
  Animals moving through air or water toward a goal frequently must contend with fluid currents, which can drift the actual path of the animal away from the direction of heading. Whether, and to what degree, animals compensate for currents depends on the species and environmental context, but plays an important role in the movement ecology of the species. In this paper, flocks of surf scoters (Melanitta perspicillata), an aquatic diving duck, were individually tracked during collective foraging in the presence of sideward water currents to assess the individual compensatory response while moving from open water toward the foraging location versus return to open water.
  
  
  RESULTS
  During short-range movement toward the foraging location, surf scoters moved more slowly, and compensated for currents by orienting diagonally into the current to maintain a perpendicular track to the goal. In contrast, during return to open water, surf scoters moved faster, and maintained a perpendicular orientation away from the foraging location, and allowed the sideward current to drift their track diagonally.
  
  
  CONCLUSIONS
  Surf scoters show a behavioural flexibility in response to currents, alternately using compensation and drift as the movement goal and consequent cost of accuracy change.
authors.affiliation: Department of Mathematics, Statistics, and Computer Science, St. Francis Xavier University, P.O. Box 5000, Antigonish, NS Canada.
authors.forename: Ryan
authors.initials: R
authors.lastname: Lukeman
authors.affiliation: Department of Mathematics, Statistics, and Computer Science, St. Francis Xavier University, P.O. Box 5000, Antigonish, NS Canada.
authors.forename: Alexis
authors.initials: A
authors.lastname: Christie
authors.affiliation: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC Canada.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Ydenberg
keywords: Collective motion; Current compensation; Drift; Flocking
references.citation: Proc Natl Acad Sci U S A. 2010 Jul 13;107(28):12576-80
references.pmid: 20616032
references.citation: Curr Biol. 2008 Dec 23;18(24):1961-5
references.pmid: 19097901
references.citation: J Theor Biol. 2002 Oct 21;218(4):485-96
references.pmid: 12384051
references.citation: J Theor Biol. 2014 Aug 21;355:151-9
references.pmid: 24675619
references.citation: Curr Biol. 2011 Oct 25;21(20):R861-70
references.pmid: 22032194
references.citation: J Exp Biol. 2006 Oct;209(Pt 20):3974-83
references.pmid: 17023591