<b>Host personality and seasonal parasitism risk do not account for egg rejection behavior in the azure-winged magpie</b>

Recent studies have shown that host egg rejection behavior varies according to personality traits and parasitism risk. However, these relationships have not been clearly determined.The study was conducted in April–June 2024. The study site was located in Fusong County, Baishan City, Jilin Province, northeastern China (42°42ʹ N, 127°01′ E). The region is located in the temperate zone with an average elevation of 481 meters, a continental monsoon climate with cold and snowy winters, and an average annual temperature of 4°C (Yang et al., 2019).The azure-winged magpie belongs to the order Passeriformes and family Corvidae. It is widely distributed in the eastern Palearctic region and exhibits cooperative breeding behavior. Azure-winged magpies are typical resident birds in most parts of China (Zheng 2023); however, azure-winged magpies at the study site appeared in surrounding coniferous forests near populated areas only around April. These birds mainly used sporadically distributed artificially planted spruce (<i>Picea asperata</i>) and red pine (<i>Pinus koraiensis</i>) woods for nesting (Liu et al. 2023). In Europe, the azure-winged magpie is a host of the great spotted cuckoo (<i>Clamator glandarius</i>) (Avilés et al., 2004). In Japan, it serves as an important host for the common cuckoo (Nakamura, 1990). In China, it is parasitized by common cuckoos, Indian cuckoos (<i>Cuculus micropterus</i>) (Nakamura et al., 1998), and Asian koels (<i>Eudynamys scolopaceus</i>) (Lin et al., 2024).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<i> </i>(<i>Cyanopica cyanus</i>). 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 recognition behavior.