Wild‐caught European starlings (Sturnus vulgaris) were exposed to a learning task to determine whether heart rate (HR) and behavior responses to the learning activated the sympathetic nervous system. Birds learned to discriminate between images of opposite convexity (concave and convex) based on shading cues in a closed economy (food only available through task completion). Once learned, the task was changed in three ways: (a) manipulating the angle and shape of the image; (b) altering the availability of the task; and (c) reversing the positive stimulus. HR, used as an index of catecholamine release, was measured during each change to determine whether having to alter previously established behaviors to learn new behaviors elicited a sympathetic response. Starlings decreased their HR during the initial discrimination training and did not alter their HR when presented with modified images or when the positive stimulus was reversed. However, HR increased when the task became unavailable and decreased upon its return, suggesting that preventing task performance was perceived as stressful. Birds also modified their behavior when tasks were changed. The number of trials per minute decreased during the reversal treatment, as did the success rate, suggesting that starlings may try to conserve energy when access to food diminishes. This is also supported by the decrease in perch hops per minute when the task was unavailable and the subsequent increase upon its return. Overall, these results suggest that learning per se does not activate the sympathetic nervous system and, therefore, is not a stressor for wild birds.

中文翻译：

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学习对欧洲椋鸟（Sturnus vulgaris）心率和行为的影响。

野生捕获的欧洲椋鸟（Sturnus vulgaris）接受一项学习任务，以确定心率（HR）和对学习的行为反应是否激活了交感神经系统。鸟类学会了根据封闭经济中的阴影线索（只有通过完成任务才能获得食物）来区分相反凸面（凹面和凸面）的图像。一旦学会，任务就会以三种方式改变：（a）操纵图像的角度和形状；(b) 改变任务的可用性；(c) 扭转积极的刺激。HR，用作儿茶酚胺释放的指标，在​​每次改变期间进行测量，以确定是否必须改变先前建立的行为来学习新行为会引起交感神经反应。椋鸟在最初的辨别训练中降低了心率，但在看到修改后的图像或逆转积极刺激时并没有改变它们的心率。然而，当任务不可用时，HR 会增加，而当任务返回时，HR 会下降，这表明阻碍任务执行被认为是有压力的。当任务改变时，鸟类也会改变它们的行为。在逆转治疗期间，每分钟的尝试次数减少，成功率也减少，这表明椋鸟在食物获取减少时可能会试图保存能量。当任务不可用时每分钟的栖息跳跃数减少以及任务返回时的随后增加也支持了这一点。总的来说，这些结果表明学习本身不会激活交感神经系统，因此不会对野生鸟类造成压力。