Stanek Jenna E, Thompson Brent E, Milligan Sarah E, Tranquillo Keegan A, Fettig Stephen M, Hathcock Charles D
Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Bandelier National Monument, Los Alamos, NM 87544, USA.
Animals (Basel). 2022 Feb 12;12(4):454. doi: 10.3390/ani12040454.
Birds are good indicators of environmental change and are often studied for responses to climate. Many studies focus on breeding birds, while fewer look at the migration period, which is a critical time for many birds. Birds are more susceptible to unusual climatic events during their migration due to the metabolic stress of long-distance movements. In the fall of 2020, an unusual cold weather event coupled with drought and wildfire smoke led to a large avian mortality event in New Mexico. Later analysis pointed to the mortality being largely due to starvation. This was the impetus for our research. We used 11 years of fall bird banding data from two locations, along with local drought indices, to determine what predicts avian health during the migration period. We used fat score data from over 15,000 individual birds to assess whether drought indices, age, diet, or residency influenced avian health using multiple logistic regression. We found that the probability of positive fat scores decreased as drought severity increased for younger, insectivorous, migratory birds. Insectivores had a higher probability of receiving a fat score greater than zero relative to local drought conditions, which is important, since many North American insectivores are in steep decline. Migratory birds showed a greater response than year-round residents, and older birds showed a lower but significant response compared to hatch-year birds. Our results suggest that migratory insectivores in the southwestern United States may be less resilient to drought-related climate change.
鸟类是环境变化的良好指示生物，常被研究其对气候的反应。许多研究聚焦于繁殖期的鸟类，而关注迁徙期的研究较少，然而迁徙期对许多鸟类来说是关键时期。由于长途迁徙带来的代谢压力，鸟类在迁徙过程中更容易受到异常气候事件的影响。2020年秋季，一场异常寒冷的天气事件，再加上干旱和野火烟雾，导致新墨西哥州发生了大规模鸟类死亡事件。后续分析表明，死亡主要是由于饥饿。这成为了我们开展研究的动力。我们利用来自两个地点的11年秋季鸟类环志数据，以及当地的干旱指数，来确定在迁徙期预测鸟类健康状况的因素。我们使用了超过15000只个体鸟类的脂肪评分数据，通过多元逻辑回归来评估干旱指数、年龄、饮食或居留情况是否会影响鸟类健康。我们发现，对于较年轻的食虫候鸟而言，随着干旱严重程度的增加，脂肪评分呈正值的概率会降低。相对于当地干旱状况，食虫鸟类获得大于零的脂肪评分的概率更高，这一点很重要，因为许多北美食虫鸟类的数量正在急剧下降。候鸟比留鸟表现出更大的反应，与当年幼鸟相比，年长鸟类的反应较低但显著。我们的研究结果表明，美国西南部的食虫候鸟可能对与干旱相关的气候变化适应能力较差。
