Skip to main content

Research Repository

Advanced Search

Social network correlates of food availability in an endangered population of killer whales, Orcinus orca

Morrell, Lesley J.; Foster, Emma A.; Franks, Daniel W.; Morrell, Lesley; Balcomb, Ken C.; Parsons, Kim M.; van Ginneken, Astrid; Croft, Darren P.


Lesley J. Morrell

Emma A. Foster

Daniel W. Franks

Ken C. Balcomb

Kim M. Parsons

Astrid van Ginneken

Darren P. Croft


For the majority of social species, group composition is dynamic, and individuals are interconnected in a heterogeneous social network. Social network structure has far-reaching implications for the ecology of individuals and populations. However, we have little understanding of how ecological variables shape this structure. We used a long-term data set (1984-2007) to examine the relationship between food availability and social network structure in the endangered southern resident killer whales. During the summer months individuals in this population feed primarily on chinook salmon, Oncorhynchus tshawytscha, which show annual variation in abundance. We tested the hypothesis that temporal variation in chinook salmon will correlate with variation in social network structure. Using a null model that controlled for population demography, group size and sampling effort, we found a significant relationship between the connectivity of the social network and salmon abundance, with a more interconnected social network in years of high salmon abundance. Our results demonstrate that resource availability may be an important determinant of social network structure. Given the central importance of the social network for population processes such as the maintenance of cooperation and the transmission of information and disease, a change in social network structure caused by a change in food availability may have significant ecological and evolutionary consequences. © 2012 The Association for the Study of Animal Behaviour.


Foster, E. A., Franks, D. W., Morrell, L., Balcomb, K. C., Parsons, K. M., van Ginneken, A., & Croft, D. P. (2012). Social network correlates of food availability in an endangered population of killer whales, Orcinus orca. Animal behaviour, 83(3), 731-736.

Journal Article Type Article
Acceptance Date Nov 29, 2011
Online Publication Date Jan 20, 2012
Publication Date 2012-03
Journal Animal behaviour
Print ISSN 0003-3472
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 83
Issue 3
Pages 731-736
Keywords Association; Chinook salmon; Clustering; Foraging; Group living; Killer whale; Orcinus orca; Prey; Social dynamics; Social organization
Public URL
Publisher URL