Eikenaar Cas, Hessler Sven, Fischer Sandra, Bairlein Franz
Institute of Avian Research, An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.
Institute of Avian Research, An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.
Gen Comp Endocrinol. 2019 May 1;275:25-29. doi: 10.1016/j.ygcen.2019.02.010. Epub 2019 Feb 10.
Wild animals typically suffer from stress when brought into captivity. This stress is characterized by elevated circulating glucocorticoid levels and weight loss. We here describe for the first time a case where a wild animal, the long-distance migrating northern wheatear, does not show signs of stress when caged. We captured these birds on a stopover site during their spring migration and caged them individually with ad libitum access to food and water. The birds were divided into four groups and were blood-sampled immediately in the field, a few hours after caging, one day after caging, or three days after caging, respectively. From these blood-samples we determined circulating corticosterone level. Food intake and body mass were also monitored. We found that, with very few exceptions, corticosterone levels were low and did not differ among the groups. Accordingly, almost all birds consumed huge quantities of food and substantially increased their body mass. Together these results clearly show that caging does not result in indications of stress in wild migrating northern wheatears. Confinement-specific conditions such as restricted movement normally stress animals. We suggest migratory birds may not perceive such conditions as stressors due to their hyperphagic state, a notion that requires further testing.
野生动物被圈养时通常会遭受压力。这种压力的特征是循环糖皮质激素水平升高和体重减轻。我们在此首次描述了一个案例，一种野生动物，即长途迁徙的白斑黑石鵖，在被关入笼子时并未表现出压力迹象。我们在它们春季迁徙的中途停留地捕获了这些鸟，并将它们单独关入笼子，提供充足的食物和水。这些鸟被分成四组，分别在野外、关入笼子几小时后、关入笼子一天后或关入笼子三天后立即进行采血。从这些血样中我们测定了循环皮质酮水平。同时也监测了食物摄入量和体重。我们发现，除了极少数例外情况，皮质酮水平较低，且各组之间没有差异。相应地，几乎所有的鸟都大量进食并大幅增加了体重。这些结果共同清楚地表明，圈养并不会导致野生迁徙白斑黑石鵖出现压力迹象。诸如活动受限等特定的圈养条件通常会给动物带来压力。我们认为候鸟可能由于其贪食状态而不会将此类条件视为压力源，这一观点需要进一步验证。
