Body size mediated coexistence in swans

Katharina A.M. Engelhardt, Mark E. Ritchie, James A. Powell

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Differences in body sizes may create a trade-off between foraging efficiency (foraging gains/costs) and access to resources. Such a trade-off provides a potential mechanism for ecologically similar species to coexist on one resource. We explored this hypothesis for tundra (Cygnus columbianus) and trumpeter swans (Cygnus buccinator), a federally protected species, feeding solely on sago pondweed (Stuckenia pectinata) tubers during fall staging and wintering in northern Utah. Foraging efficiency was higher for tundra swans because this species experienced lower foraging and metabolic costs relative to foraging gains; however, trumpeter swans (a) had longer necks and therefore had access to exclusive resources buried deep in wetland sediments and (b) were more aggressive and could therefore displace tundra swans from lucrative foraging locations. We conclude that body size differentiation is an important feature of coexistence among ecologically similar species feeding on one resource. In situations where resources are limiting and competition for resources is strong, conservation managers will need to consider the trade-off between foraging efficiency and access to resources to ensure ecologically similar species can coexist on a shared resource.

Original languageEnglish (US)
Article number643694
JournalThe Scientific World Journal
StatePublished - 2014

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Environmental Science


Dive into the research topics of 'Body size mediated coexistence in swans'. Together they form a unique fingerprint.

Cite this