Ecology and Evolutionary Biology
Dr. Alexander Cruz
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.
Nishikawa, Elise, "The wag-display of the blue-crowned motmot (Momotus momota) as a predator-directed signal" (2011). Undergraduate Honors Theses. 656.