Predator-elicited visual signal: why the turquoise-browed motmot wag-displays its racketed tail

Racketed tail of the male and female turquoise-browed motmot: male but not female tail length correlates with pairing success, performance, and reproductive success

“…These studies have concluded that the genetic correlation hypothesis, which was the null, was likely to account for the expression of what the authors interpreted as nonfunctional female traits (but see Hill 2002 for updated results). Likewise, I found no evidence for sexual selection on female tails; however, previous work (Murphy 2006(Murphy , 2007a showed that both sexes are likely to gain adaptive benefits in a nonsexually selected context by displaying their tail in a pendulum-like fashion (wag display) upon encountering a predator. This research experimentally showed a link between the presence of a predator and the performance of the wag display and suggested that the wag display is not directed at conspecifics but is instead directed to the predator and communicates awareness to deter pursuit or ambush.…”

“…Because body size is correlated with the size of many tail components (Murphy 2007b Statistical analyses were conducted using JMP software (SAS Institute, Cary, NC, 1989-2006. Multiple logistic regression was used to investigate the relationship between tail plumage and pairing success and between tail plumage and whether individuals fledged at least one young.…”

“…In previous research (Murphy 2006(Murphy , 2007a, I demonstrated that both males and females perform a side-to-side wag display with their long racketed tails in the presence of predators. Results from predator presentation experiments showed that the predator was the likely receiver of the signal, and data were consistent with the hypothesis that the wag display deters predators from attempting to ambush the signaler.…”

“…Natural selection can favor elaborate traits that serve a myriad of purposes among birds, including aerodynamic structures that aid in flight (Balmford et al 1993) and a diverse range of intraspecific signals, such as signals of aposematism (Dumbacher et al 1992), signals to startle prey to facilitate foraging (Mumme 2002), signals to distract predators from nests (Deane 1944), signals to disorient predators during attack (Palleroni et al 2005), and signals to deter predator pursuit (Woodland et al 1980) or predator ambush (Murphy 2006(Murphy , 2007a.…”

Same trait, different receiver response: unlike females, male American goldfinches do not signal status with bill colour

“…Some research has revealed that male and female ornamental traits may function in different selective contexts; for example, an elaborate trait may have sexually or socially selected ornamental function in one sex, while in the other sex, the trait may have evolved in response to natural selection for viability (e.g. for antipredation : Heinsohn, Legge, & Endler, 2005;Montgomerie, Lyon, & Holder, 2001;Murphy, 2006Murphy, , 2007Packer, 1983) . In addition, studies have found that elaborate traits may be functional in males, yet be expressed in females as nonadaptive by-products of genetic correlation (Cuervo, de Lope, & Møller, 1996;Lande, 1980;Muma & Weatherhead, 1991;Murphy & Pham, 2012;Wolf, Casto, Nolan, & Ketterson, 2004).…”