An important goal of urban ecology is determining what differentiates urban-tolerant populations of birds from their non-urban ancestors and urban-intolerant species. One key to urban success may be reacting appropriately to human activity, and the degree to which birds view humans as threats can be quantified by their escape behavior. Understanding individual-level plasticity, however, requires the tracking of known individuals. We compared flight-initiation distances (FID) and distances fled (DF) from approaches by a human across urban and non-urban populations of individually-marked Dark-eyed Juncos (Junco hyemalis) in southern California. The urban population is more tolerant to people as evidenced by attenuated FIDs and DFs relative to non-urban birds. Although individual urban birds either habituated or sensitized to repeated approaches, there was no significant pattern at the population level. Overall, the behavioral patterns exhibited by urban juncos are more supportive of in situ evolution than either being a biased sample from an ancestral non-urban population or intrinsic behavioral plasticity that produces a uniform adjustment to urban life.

中文翻译：

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城市黑眼jun（Junco hyemalis）对人类活动的耐受性的个体差异。

城市生态学的一个重要目标是确定使城市耐受鸟类与非城市祖先和城市非耐受物种有何区别。城市成功的关键之一可能是对人类活动做出适当反应，而鸟类将人类视为威胁的程度可以通过其逃逸行为来量化。但是，了解个人级别的可塑性要求跟踪已知的个人。我们比较了人类跨越加利福尼亚南部市区和非市区人口的，带有单独标记的黑眼Jun豆（Junco hyemalis）的进场飞行起始距离（FID）和逃离距离（DF）。与非城市鸟类相比，FIDs和DFs的减弱证明了城市人口对人的宽容。尽管个别城市鸟类已习惯或对重复进近很敏感，在人口水平上没有明显的格局。总体而言，与作为原始祖先非城市人口的偏见样本或固有行为可塑性（对城市生活产生统一的调整）相比，城市juncos表现出的行为模式更支持原位进化。