Sexual signals, risk of predation and escape behavior

Abstract

Adults of many species display extravagant sexual signals during the reproductive season, apparently evolved as a means of attracting mates or repelling potential competitors, thereby inadvertently also attracting the attention of predators. Many studies have shown predation costs of sexual display. Therefore, we should expect species with the most exaggerated signals to have evolved antipredator behavior that reduces or eliminates predation costs of sexual signaling but also to have evolved behavior that allows for escape from a predator once captured. We quantified 6 aspects of escape behavior in 2105 free-living birds belonging to 80 species when handled after capture for banding. Escape behavior was species specific as demonstrated by significant consistency in behavior among individuals. Escape behavior was significantly related to susceptibility to predation by cats Felis catus and goshawks Accipiter gentilis, showing that escape behavior is under current selection. Escape behavior was related to the ease of feather loss estimated in a previous study but also to the frequency of tailless individuals recorded in the field. Thus, escape behavior reported here was cross-validated against other aspects of antipredator behavior shown to reflect risk of predation. Aspects of escape behavior differed significantly between males and females (biting, fear screams, and feather loss). Sexually dichromatic species differed in escape behavior from monochromatic species by having a reduced frequency of fear screams and increased tonic immobility. These findings suggest that exposure to risk of predation has modified escape behavior in relation to sexual coloration. Key words: alarm calls, escape behavior, fear scream, predation, sex, signaling, tonic immobility. [Behav Ecol]