Pre-laying vocal activity as a signal of male and nest stand quality in goshawks

Abstract

In this study we examined male vocalisation patterns as a measure of individual and nest stand quality in goshawk Accipiter gentilis. We related the male call rate at dawn (considered to be part of a reproductive strategy) to breeding success and nest stand structure. We recorded the two main chattering-type calls of nine goshawks during the 3 months preceding egg-laying (January-March). Nest stand characteristics were assessed by means of six parameters of nest trees and four parameters of the forest stands within a 1-ha plot. The vocalisations varied significantly among individuals: successful breeders had longer vocalisations and began vocalising earlier than failed ones. Males that successfully reproduced also differed significantly from unsuccessful ones in nest stand characteristics. The results indicate that dawn vocal activity may be considered a honest advertisement of male quality, as well as the quality of its nest stand, expressed by breeding success. The conservation concerns we may gain about territory quality in relation to male vocal activity are also discussed.