Heat stress in a high-latitude seabird:: effects of temperature and food supply on bathing and nest attendance of great skuas Catharacta skua
Heat stress in a high-latitude seabird:: effects of temperature and food supply on bathing and nest attendance of great skuas Catharacta skua
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DOI：
10.1111/j.2008.0908-8857.04187.x
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发表时间：
2008-03-01
影响因子：
1.7
通讯作者：
Hamer, Keith C.
中科院分区：
文献类型：
--
作者：
Oswald, Stephen A.;Bearhop, Stuart;Hamer, Keith C.
适合在高纬度地区成功繁殖的鸟类，例如大贼鸥（Catharaacta skua），在温和的气候下可能会遇到散热问题。大贼鸥花时间在靠近繁殖地的淡水地点沐浴，在这里，我们研究了三个繁殖季节中热应激对成年贼鸥沐浴、觅食和筑巢的影响，其中猎物（1组白鹬Ammodytes marinus）的可用性存在显着变化。成年人的沐浴活动表现出与热应激条件相匹配的昼夜变化。此外，更多的鸟类在平均热应激较高的日子里洗澡，这表明洗澡在体温调节中发挥着作用。在粮食供应不足的年份，当领地的成年出勤率较低时，洗澡的数量就会减少，这可能是因为出勤率较低减少了父母在不让雏鸟无人看管的情况下洗澡的机会。雏鸟通常由雌性父母看管并由雄性喂养，但在食物供应不足的情况下，在高热应激的日子里，繁殖对的领地出勤率特别低，在气温超过 14 摄氏度的情况下，雏鸟经常无人看管。无人看管的雏鸟有被邻近同种动物杀死的风险，而且在黄鳝种群数量较低的两年里，雏鸟的羽翼存活率也很低。我们的研究表明，对于大贼鸥来说，气候变化对猎物的间接影响和对成年贼经历的热应激的直接影响可能是相加的。
Birds such as great skuas Catharacta skua adapted for successful breeding at high latitudes may experience problems of heat dissipation in mild climates. Great skuas spend time bathing at freshwater sites close to breeding territories and here, we examine impacts of heat stress on bathing, foraging and nest attendance of adults during three breeding seasons with marked variation in the availability of prey (1-group sandeels Ammodytes marinus). Adults exhibited diurnal variation in bathing activity that matched heat-stress conditions. Moreover more birds bathed on days of higher average heat stress, suggesting that bathing plays a role in thermoregulation. Bathing numbers were lower in years of poor food availability, when adult attendance at territories was low, probably because lower attendance reduced the opportunity for parents to bathe without leaving chicks unattended. Chicks are normally guarded by female parents and fed by males but under conditions of low food availability territorial attendance of breeding pairs was particularly low on days of high heat stress, with chicks regularly left unattended at air temperatures exceeding 14 degrees C. Unattended chicks are at risk of being killed by neighbouring conspecifics and survival of chicks to fledging was low in the two years of low sandeel stocks. Our study indicates that for great skuas, indirect effects of climate change on prey stocks and direct effects on heat stress experienced by adults may be additive.