Species that are constantly exposed to disturbances, such as human disturbance or non-lethal contacts with predators or conspecifics, can experience chronic stress. Within a species range, variation in the frequency and predictability of such disturbances can lead to population differences in stress responses. Here, we investigated the stress response of Little Penguins Eudyptula minor to an introduced predator and a conspecific at two South Australian colonies that differed in habitat, conspecific density, levels of human disturbance and predation risk (high, low). We used playback experiments of Cat Felis catus or Little Penguin calls and recorded the behaviour and physiological (heart rate) response of adults in relation to playback type (Cat, Penguin) as well as habitat characteristics (habitat type, nest type, nest visibility) and number of conspecifics present. Our results showed that individuals from the high-disturbance colony (also living in a mixed habitat with fewer neighbours) exhibited higher vigilance and heart rate responses than individuals from the low-disturbance colony (living in a closed habitat with a high number of neighbours). Our results highlight that guidelines for managing penguin species cannot be generalized across populations and need to be colony-specific.

中文翻译：

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在人类干扰和捕食风险水平不同的两个小企鹅种群中，对压力源的行为和心率反应

经常受到干扰的物种，例如人类干扰或与捕食者或同类的非致命接触，可能会经历慢性压力。在一个物种范围内，这种干扰的频率和可预测性的变化会导致压力反应的种群差异。在这里，我们调查了小企鹅Eudyptula minor对引入的捕食者和同种物种的应激反应，这些物种在栖息地、同种密度、人类干扰水平和捕食风险（高、低）方面不同的两个南澳大利亚殖民地。我们使用了 Cat Felis catus 的回放实验或 Little Penguin 呼叫并记录与回放类型（猫、企鹅）以及栖息地特征（栖息地类型、巢穴类型、巢穴可见度）和同种物种数量相关的成年人的行为和生理（心率）反应。我们的结果表明，来自高干扰群体（也生活在邻居较少的混合栖息地）的个体比来自低干扰群体（生活在具有大量邻居的封闭栖息地）的个体表现出更高的警惕性和心率反应. 我们的结果强调，管理企鹅物种的指南不能在种群中推广，并且需要针对特定​​群体。