Song post exposure, song features, and predation risk

Male birds use song to attract. Mates and deter other males, hot ill doing so, they also attract. the attention of predators and parasites. Such viability Costs are inherent in reliable signals, potentially causing females to prefer mates that. display from the most. exposed sites. However, viability costs, of sexual signals may be ameliorated by affecting the choice of microhabitat, which in turn may affect the design of song features that are most efficiently transmitted in this microhabitat. We estimated the exposure of song posts (microsites used by males when singing) Used by passerine birds in relation to prey selection by the sparrowhawk Accipiter nisus, by calculating the proportion of Males that Sang from song posts that. were at the maximum level Of the vegetation, in all attempt to (quantify the cost.; of sexual selection. We quantified prey susceptibility to predation as the difference between the log-transformed observed number Of prey minus the log-transformed expected number of prey ill the environment. This prep susceptibility index increased with increasing song post exposure similarly in sexually dichromatic and monochromatic species, although the prey susceptibility index was related to sexual dichromatism. Song post exposure was dependent on habitat, but comparative models controlling For the potentially confounding effects Of habitat, sexual dichromatism, hole nesting, coloniality, body mass, cognitive capacities, and flying abilities indicated that the relationship between the prey susceptibility index and song post exposure is strong. Path analyses of the relationship between song post exposure sexual dichromatism, and prey susceptibility index revealed that. selection acting oil sexual dichromatism and song post. exposure has secondary impact Oil prey susceptibility index. The opposite causal mechanisms by which predation affects sexual traits are less likely. These models suggest that female preference for high song posts or dichromatic plumage increases predation risk on an evolutionary time scale.