Eurasian tree sparrows are more food neophobic and habituate to novel objects more slowly than house sparrows

We captured wild Eurasian tree sparrows (Passer montanus) from a private field site in Illinois, United States. Sparrows were transported to Louisiana State University where we conducted neophobia trials. These behavioural assays consisted of weeklong trials to assess responses to novel objects and foods as well as the sparrows' abilities to habituate to repeated presentations of the same initially novel object. We followed methods used in Kimball et al. 2022 (Novel objects alter immediate early gene expression globally for ZENK and regionally for c-fos in neophobic and non-neophobic house sparrows, published in Behavioural Brain Research). Behavioural trials were recorded, and then the recordings were watched by two observers (KJK and EBC). Video watchers noted the time during the hour-long trials at which each sparrow approached and fed from the food dish, where novel objects or foods were placed. Because male and female Eurasian tree sparrows cannot be distinguished by plumage characteristics, we determined the sex of each sparrow by examining gonads in the body cavity after the birds were euthanized after behavioural trials. We compared the Eurasian tree sparrows' behavioural responses to those of house sparrows (Passer domesticus) collected in a previous study (Kimball et al. 2022). Again, house sparrow data were collected using the same methods. The manuscript and its associated dataset for the house sparrow study can be accessed here: https://doi.org/10.1016/j.bbr.2022.113863. For more details on our methods, please read the associated manuscript.本研究于美国伊利诺伊州一处私人野外样地捕获野生欧亚树麻雀（Passer montanus），将其转运至路易斯安那州立大学开展新物恐惧症（neophobia）行为实验。本次行为学测定实验为期一周，旨在评估受试个体对新奇物体与新奇食物的反应，以及其对重复呈现初始新奇物体的习惯化能力。实验流程遵循Kimball等人2022年发表于《行为脑研究》（Behavioural Brain Research）的研究方法，该原文主题为「新物体可改变新物恐惧症与非新物恐惧症家麻雀的ZENK基因全脑即时早期基因表达及c-fos基因脑区特异性表达」。行为实验全程录像，由两名观察员（KJK与EBC）对录像进行回放分析，记录每只麻雀在1小时实验期间，靠近并取食放置有新奇物体或食物的食槽的具体时刻。由于欧亚树麻雀无法通过羽色区分雌雄，故在行为实验结束后对受试个体实施安乐死，通过剖检体腔中的性腺确定其性别。本研究将欧亚树麻雀的行为反应与既往研究（Kimball等人2022）中捕获的家麻雀（Passer domesticus）的行为反应进行对比，家麻雀的数据采集采用完全一致的实验流程。家麻雀相关研究的论文及配套数据集可通过以下链接获取：https://doi.org/10.1016/j.bbr.2022.113863。若需了解本研究实验方法的更多细节，请查阅配套学术论文。