Breeding density affects the honesty of bird vocal displays as possible indicators of male/territory quality

摘要: Vocal displays are supposed to be an honest signal of the phenotypic and genetic quality individuals their territory. Moreover, interactions nearly always associated with in aggregations, function could part explained as social behaviour. Conspecific density has been shown a particularly strong proximate ultimate factor acting on several individual/population features; thus, it may expected affect vocal behaviour too. Here, I investigate hypothesis that, long-lived, territorial species, affects mated males, masking honesty possible male/territory quality. Each month listened dusk calls 17 breeding male Eurasian Eagle Owls Bubo bubo during prelaying period. Nine males bred lowdensity situation, other eight high-density one. was found call features signals and/or territory The display reliable predictor fitness measured productivity persisted only situations high owl density, where male‐male competition stronger. Accommodation activity allows minimize costs aggressive calling by adjusting territoriality threshold local conditions. results this study emphasize importance, when investigating evolution maintenance or sexual signals, considering environmental context experienced individual, thereby corroborating idea that contributes signalling.