Data for: Shy-boldness cannot predict egg rejection in the Japanese tit

In response to brood parasitism, which significantly reduces the reproductive success of avian hosts, hosts have evolved the ability to recognize and reject parasitic eggs. Many studies have revealed the influencing factors of egg recognition and egg rejection, and recent study found that host personality, along the bold-shy continuum, can influence egg rejection behavior. In addition, the egg rejection behavior of hosts differed among populations, suggesting that individuals with different personalities may evolve various adaptive behaviors under different parasitic pressures, but there has been few relevant experiments to verify this. In the present study, two populations of the Japanese tit Parus minor distributed in China were used to examine whether there were differences in egg rejection behavior of individuals with different personalities. The results showed that egg rejection rates of bold individuals (who remained in the nest box when encountering human invaders) and shy indivi..., During the breeding season (April-June) of year 2022, when Japanese tits were found occupying nest boxes, breeding nests were regularly monitored to determine the dates of the first eggs. Female Japanese tits usually started incubation the day after laying their last egg (Zhang et al. 2020), and therefore, we defined the date when the females laid their last eggs as day 0 of the incubation period. After determining that the Japanese tits had entered the incubation period, we began an escape behavior test and a foreign egg recognition experiment among the female Japanese tits.
In order to measure escape behavior, researchers slowly approached the nest box from about 10 m and gazed at the hole to record whether the females flew away, though the orientation of the approaching was adjusted according to location of focal nest boxes. If the female did not fly out from nest boxes when the experimenter went under the tree hung up nest box, we climbed the tree. We defined females that flew away..., We used generalized linear models (GLMs) (logit-link function) to analyze the impact of escape behavior of the female Japanese tits on whether they rejected foreign eggs. The egg rejection behavior of the females (rejected=1; accepted=0) was the response variable. For analyses on the same population (i.e., in DZ or ZJ), escape behavior (escaped: shy; did not escape: bold), clutch size, and date of egg experiment were the explanatory variables. For analyses on the two populations combined, escape behavior, location, clutch size, and date of egg experiment were the explanatory variables. Likelihood ratio tests were used to obtain p-values. Data analysis was completed using R 4.1.0 software, with a two-tailed test and a significance level of α=0.05.