Environmental constraints can explain clutch size differences between urban and forest blue tits: Insights from an egg removal experiment

Urban environments present novel ecological challenges to wild species. In birds, urban populations generally exhibit reduced clutch sizes compared to forest populations. However, whether smaller urban clutches are adaptive or a result of environmental constraints is unclear. To investigate these two hypotheses, we quantified the ability of urban and non-urban blue tits (Cyanistes caeruleus) to lay new eggs after an experimental manipulation aimed to increase egg production. We removed the first four eggs laid by urban and forest birds to test their ability to produce new eggs. If the urban environment imposes constraints on egg production, we predicted that urban birds would not lay new eggs. If the small clutches of urban birds are an adaptive response, we predicted they would lay new eggs to reach the optimal clutch size for the environment. Consistent with the environmental constraint hypothesis, our results suggest that urban females do not lay new eggs to the same extent as forest..., , , --- # **Data from:** Environmental constraints can explain clutch size differences between urban and forest blue tits: Insights from an egg removal experiment This dataset contains all the data that was collected and analysed for a project investigating whether urban and forest blue tit populations respond differently to an egg removal experiment. --- Mark D. Pitt, Norah S.S. Alhowiti, Claire J. Branston, Eugenio Carlon, Jelle J. Boonekamp, Davide M. Dominoni, Pablo Capilla-Lasheras. **Environmental constraints can explain clutch size differences between urban and forest blue tits: insights from an egg removal experiment**. --- For any further information, please contact: Mark Pitt, email: [[e-mail]](mailto:[e-mail]) ## Description of code: The statistical software used to analyse our data was R v.4.3.2. Scripts are numbered in order of where they appear in the manuscript. Each script contains a small description to the section of the manuscript to...城市环境对野生生物提出了全新的生态挑战。在鸟类中，城市种群的窝卵数（clutch size）通常低于森林种群。然而，城市种群较小的窝卵数究竟是适应性演化的结果，还是环境限制所致，目前尚无定论。为验证这两种假说，我们量化了城市与非城市青山雀（Cyanistes caeruleus）在旨在提升产卵量的实验操纵后的补卵能力。我们移除了城市与森林种群鸟类所产的前四枚卵，以检测它们补产新卵的能力。若城市环境对产卵存在限制，我们预测城市鸟类不会补产新卵；若城市种群的小窝卵数属于适应性响应，则它们会补产新卵以达到该环境下的最优窝卵数。本研究结果与环境限制假说一致，表明城市雌性青山雀的补卵能力与森林种群存在显著差异…… # **数据来源：**《环境限制可解释城市与森林种群青山雀的窝卵数差异——基于卵移除实验的启示》 本数据集涵盖了一项探究城市与森林种群青山雀对卵移除实验响应差异的研究项目中，所有采集并经分析处理的数据。 --- 马克·D·皮特（Mark D. Pitt）、诺拉·S·S·阿尔霍维蒂（Norah S.S. Alhowiti）、克莱尔·J·布兰斯顿（Claire J. Branston）、欧金尼奥·卡隆（Eugenio Carlon）、耶勒·J·布恩坎普（Jelle J. Boonekamp）、戴维德·M·多米诺尼（Davide M. Dominoni）、巴勃罗·卡皮利亚-拉舍拉斯（Pablo Capilla-Lasheras）。**《环境限制可解释城市与森林种群青山雀的窝卵数差异——基于卵移除实验的启示》** --- 如需进一步获取相关信息，请联系：马克·皮特，电子邮箱：[[e-mail]](mailto:[e-mail]) ## 代码说明： 本研究用于数据分析的统计软件为R v.4.3.2。脚本按照其在论文手稿中的出现顺序进行编号，每个脚本均附带一段简短说明，对应手稿中的对应章节……