Persistent Link:
http://hdl.handle.net/10150/282865
Title:
Information use and species interactions in a hummingbird guild
Author:
Sandlin, Elizabeth Ann
Issue Date:
1999
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
How might an individual's ability to learn environmental information affect competitive interactions among species? Learned behavior can influence foraging decisions. Competition for food resources can influence patterns of species coexistence via habitat selection. I wondered if both learned behavior and competition might act together to influence interactions among species. I used Rosenzweig's shared-preference isoleg theory to predict four possible ways that differences in environmental information could affect density-dependent habitat selection. To test these predictions, I conducted field experiments to examine the foraging behavior of free-living hummingbirds. I studied black-chinned (Archilochus alexandri), blue-throated (Lampornis clemenciae), and magnificent (Eugenes fulgens) hummingbirds where they coexist in the Chiricahua Mts. of Southeastern AZ. I gave hummingbirds two types of habitats (rich and poor feeders) and let them learn to associate colors with feeder quality. I confirmed that learned color associations can increase hummingbird foraging efficiency. All birds shared a preference for the rich feeders. However, they will shift their preference toward poor feeders when competitor densities are high (Pimm et al. 1985). I quantified hummingbirds' preferences for the rich feeders when both competitor densities and information (via learned color cues) varied. The data support my fourth prediction---that birds foraging with complete information enjoy reduced negative effects from competition. Without complete information, the two subordinate species (black-chinned and magnificent) shifted their preference away from rich feeders in response to high densities of the dominant species (blue-throated). Each subordinate shifted in a unique way; the black-chinned reduced its foraging efficiency, while the magnificent reduced its total foraging time. Birds foraging with complete information remained highly selective on rich feeders even with high competitor densities. Thus, learned information affected competitive interactions (for rich feeders) among these species. My results require us to consider the information-gathering (e.g., learning) abilities of individual decision-makers when we evaluate density-dependent habitat selection. These results should help us better explain patterns of species diversity and distribution, especially for cases in which species learn environmental cues. This study provides the first demonstration, either theoretically or empirically, of a link between learned behavior and its cascading effects within a guild of coexisting species.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology, Ecology.; Biology, Zoology.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Ecology and Evolutionary Biology
Degree Grantor:
University of Arizona
Advisor:
Rosenzweig, Michael L.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleInformation use and species interactions in a hummingbird guilden_US
dc.creatorSandlin, Elizabeth Annen_US
dc.contributor.authorSandlin, Elizabeth Annen_US
dc.date.issued1999en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractHow might an individual's ability to learn environmental information affect competitive interactions among species? Learned behavior can influence foraging decisions. Competition for food resources can influence patterns of species coexistence via habitat selection. I wondered if both learned behavior and competition might act together to influence interactions among species. I used Rosenzweig's shared-preference isoleg theory to predict four possible ways that differences in environmental information could affect density-dependent habitat selection. To test these predictions, I conducted field experiments to examine the foraging behavior of free-living hummingbirds. I studied black-chinned (Archilochus alexandri), blue-throated (Lampornis clemenciae), and magnificent (Eugenes fulgens) hummingbirds where they coexist in the Chiricahua Mts. of Southeastern AZ. I gave hummingbirds two types of habitats (rich and poor feeders) and let them learn to associate colors with feeder quality. I confirmed that learned color associations can increase hummingbird foraging efficiency. All birds shared a preference for the rich feeders. However, they will shift their preference toward poor feeders when competitor densities are high (Pimm et al. 1985). I quantified hummingbirds' preferences for the rich feeders when both competitor densities and information (via learned color cues) varied. The data support my fourth prediction---that birds foraging with complete information enjoy reduced negative effects from competition. Without complete information, the two subordinate species (black-chinned and magnificent) shifted their preference away from rich feeders in response to high densities of the dominant species (blue-throated). Each subordinate shifted in a unique way; the black-chinned reduced its foraging efficiency, while the magnificent reduced its total foraging time. Birds foraging with complete information remained highly selective on rich feeders even with high competitor densities. Thus, learned information affected competitive interactions (for rich feeders) among these species. My results require us to consider the information-gathering (e.g., learning) abilities of individual decision-makers when we evaluate density-dependent habitat selection. These results should help us better explain patterns of species diversity and distribution, especially for cases in which species learn environmental cues. This study provides the first demonstration, either theoretically or empirically, of a link between learned behavior and its cascading effects within a guild of coexisting species.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiology, Ecology.en_US
dc.subjectBiology, Zoology.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineEcology and Evolutionary Biologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRosenzweig, Michael L.en_US
dc.identifier.proquest9923142en_US
dc.identifier.bibrecord.b39470672en_US
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