Presentation Type

Presentation

Faculty Mentor’s Full Name

Creagh Breuner

Faculty Mentor’s Department

Division of Biological Sciences

Abstract

Sexual selection theory states that male ornamentation may evolve if it helps males obtain more matings by means of male-male competition or female preference. Dominant males can monopolize limited resources to attract mates, increasing variance in male reproductive success and strengthening the effects sexual selection. While there have been several studies examining the function of ornaments in intraspecific contests, less is understood about the role of ornamentation in interspecific competition. In a population of mountain bluebirds near Ronan, MT, tree swallows arrive after mountain bluebirds are nesting, and compete directly for access to nest-boxes. A successful tree swallow intrusion often results in total brood mortality for bluebirds, so the ability of a male mountain bluebird to defend a territory is directly linked to his and his mate’s fitness. Male mountain bluebirds have structural UV-blue plumage and there is evidence that more saturated coloration is associated with increased success in defending territories. We conducted 30 minute observations at active bluebird nests and recorded the parental behavior of bluebirds such as nest attendance and feeding rate. Observations also recorded the length of tree swallow intrusions, number of intruders, and bluebird behavioral response. Through this research, we aim to explore the relationship of male mountain bluebird coloration to his and his mate’s behavior and the characteristics of tree swallow intrusions. Our findings not only provide insight into the effect of ornamentation on interspecific competition, but also serve to support hypotheses regarding status-signal honesty.

Category

Life Sciences

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Apr 27th, 2:20 PM Apr 27th, 2:40 PM

The​ ​effect​ ​of​ ​plumage​ ​coloration​ ​on​ ​nest-box​ ​competition​ ​between mountain​ ​bluebirds​ ​​Sialia​ ​currucoides​ and​ ​tree​ ​swallows​ ​​Tachycineta​ ​bicolor

UC 327

Sexual selection theory states that male ornamentation may evolve if it helps males obtain more matings by means of male-male competition or female preference. Dominant males can monopolize limited resources to attract mates, increasing variance in male reproductive success and strengthening the effects sexual selection. While there have been several studies examining the function of ornaments in intraspecific contests, less is understood about the role of ornamentation in interspecific competition. In a population of mountain bluebirds near Ronan, MT, tree swallows arrive after mountain bluebirds are nesting, and compete directly for access to nest-boxes. A successful tree swallow intrusion often results in total brood mortality for bluebirds, so the ability of a male mountain bluebird to defend a territory is directly linked to his and his mate’s fitness. Male mountain bluebirds have structural UV-blue plumage and there is evidence that more saturated coloration is associated with increased success in defending territories. We conducted 30 minute observations at active bluebird nests and recorded the parental behavior of bluebirds such as nest attendance and feeding rate. Observations also recorded the length of tree swallow intrusions, number of intruders, and bluebird behavioral response. Through this research, we aim to explore the relationship of male mountain bluebird coloration to his and his mate’s behavior and the characteristics of tree swallow intrusions. Our findings not only provide insight into the effect of ornamentation on interspecific competition, but also serve to support hypotheses regarding status-signal honesty.