title: From daily movements to population distributions: weather affects competitive ability in a guild of soaring birds.
abstract: The ability of many animals to access and exploit food is dependent on the ability to move. In the case of scavenging birds, which use soaring flight to locate and exploit ephemeral resources, the cost and speed of movement vary with meteorological factors. These factors are likely to modify the nature of interspecific interactions, as well as individual movement capacity, although the former are less well understood. We used aeronautical models to examine how soaring performance varies with weather within a guild of scavenging birds and the consequences this has for access to a common resource. Birds could be divided broadly into those with low wing loading that are more competitive in conditions with weak updraughts and low winds (black vultures and caracaras), and those with high wing loading that are well adapted for soaring in strong updraughts and moderate to high winds (Andean condors). Spatial trends in meteorological factors seem to confine scavengers with high wing loading to the mountains where they out-compete other birds; a trend that is borne out in worldwide distributions of the largest species. However, model predictions and carcass observations suggest that the competitive ability of these and other birds varies with meteorological conditions in areas where distributions overlap. This challenges the view that scavenging guilds are structured by fixed patterns of dominance and suggests that competitive ability varies across spatial and temporal scales, which may ultimately be a mechanism promoting diversity among aerial scavengers.
authors.affiliation: Department of Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK. e.l.c.shepard@swansea.ac.uk
authors.forename: Emily L C
authors.initials: EL
authors.lastname: Shepard
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Lambertucci
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001717:Birds / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D008954:Models, Biological; D011157:Population Dynamics
keywords: competition; cost of transport; energy landscape; movement ecology; scavenger; soaring
references.citation: Ecol Lett. 2012 Feb;15(2):96-103
references.pmid: 22077120
references.citation: Science. 2012 Jan 13;335(6065):211-4
references.pmid: 22246774
references.citation: J Exp Biol. 1997;200(Pt 17):2355-61
references.pmid: 9320274
references.citation: Proc Biol Sci. 2011 Sep 7;278(1718):2682-90
references.pmid: 21270037
references.citation: J Theor Biol. 2004 Jun 7;228(3):431-6
references.pmid: 15135041
references.citation: Proc Natl Acad Sci U S A. 2007 Jul 24;104(30):12398-403
references.pmid: 17609382
references.citation: J Exp Biol. 1973 Feb;58(1):239-53
references.pmid: 4705622
references.citation: PLoS One. 2011;6(11):e27375
references.pmid: 22087301
references.citation: Ecology. 2012 Jan;93(1):29-34
references.pmid: 22486084
references.citation: Science. 2002 Aug 30;297(5586):1548-51
references.pmid: 12202829
references.citation: Science. 2000 Apr 7;288(5463):100-6
references.pmid: 10753108
references.citation: Curr Biol. 2011 Oct 25;21(20):R861-70
references.pmid: 22032194
references.citation: J Exp Biol. 2007 Jan;210(Pt 1):82-90
references.pmid: 17170151
references.citation: PLoS One. 2010 Nov 11;5(11):e13956
references.pmid: 21085655
references.citation: Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4139-43
references.pmid: 18316724
references.citation: J Clim. 2017 Jun 20;Volume 30(Iss 13):5419-5454
references.pmid: 32020988
references.citation: J R Soc Interface. 2012 Dec 7;9(77):3351-8
references.pmid: 22951344
references.citation: Curr Biol. 2006 Jul 25;16(14):R527-9
references.pmid: 16860724
references.citation: Am Nat. 2013 Sep;182(3):298-312
references.pmid: 23933722