Abstract
Brood parasitism reduces the reproductive success of hosts and many host birds have evolved a range of anti-parasitism strategies, including egg recognition and egg rejection. Recent studies have shown that host egg rejection behavior can vary according to personality traits and parasitism risk. However, these relationships have not been clearly determined. The aim of this study was to further investigate the influence of seasonal parasitism pressure and host personality traits on egg rejection behavior in the azure-winged magpie (Cyanopica cyanus). Our results showed no significant difference in the proportion of egg rejection between hosts with low (before the arrival of cuckoos) and high (after the arrival of cuckoos) parasitism pressure. In addition, no significant difference was detected in the proportion of egg rejection between bold individuals (shorter flight initiation distance, FID) and shy individuals (longer FID). We hypothesized that the relatively weak effect of the presence or absence of cuckoos on this species could be attributed to their inherently strong egg recognition abilities. Moreover, the quantification of host behavior along a single personality axis (boldness-shyness) may be insufficient to capture behavioral differences that arise from the combined effects of various personality traits. Our study provides novel insights into the influence of seasonal parasitism risk and personality traits on host egg rejection behavior.