Undergraduate Honors Theses

Thesis Defended

Spring 2011

Document Type

Thesis

Department

Ecology and Evolutionary Biology

First Advisor

Dr. Alexander Cruz

Abstract

This study addresses whether the tail wagging displayed in the family Momotidae serves as a signal directed towards predators to deter pursuit, as supported by previous research on the turquoise-browed motmot (Eumomota superciliosa). The blue-crowned motmot (Momotus momota) demonstrates several characteristics: territoriality, high site fidelity, impaired flight performance, and sedentary habits that could make the bird more vulnerable to prey-stalking and ambushing predators. Like other motmots, the blue-crowned motmot performs an exaggerated tail-wagging motion when presented with a potential predator. I studied the different reactions elicited by four treatments to examine if tail wagging was directed towards a predator that had been visually located by the displaying motmot. I presented either an avian predator or non-predator model or played back an avian call from a predator or a non-predator to motmots, and observed behaviors. Motmots were significantly more likely to wag-display (p = 0.0009) upon seeing an ambush predator model (a perched bird of prey), more likely to not interrupt normal behavior like foraging when presented with a non-predatory control call, and subjects never approached either of the predator stimulus trials. Despite the more disturbed study site and niche differences between the blue-crowned motmot and the turquoise-browed motmot, my results in M. momota are consistent with, and corroborate, previous research on the latter species, suggesting that motmots may use the wag-display as a pursuit-deterrent signal to advertise awareness of the predator. In the blue-crowned motmot, because the visual signal of the wag-display draws attention to the bird, it is presumably more advantageous to signal to a predator that has been sighted rather than to a predator of uncertain location. Additionally, I observed captive motmots and noted an alternate tail display that was associated with more aggressive behavior.

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