Wildfires and invasive species have caused widespread changes in western North America’s shrub-steppe landscapes. The bottom–up consequences of degraded shrublands on predator ecology and demography remain poorly understood. We used a before–after paired design to study whether Golden Eagle (Aquila chrysaetos) diet and nestling survivorship changed following wildfires in southwestern Idaho, USA. We assessed burn extents from 1981 to 2013 and vegetation changes between 1979 (pre-burn) and 2014 (post-burn) within 3 km of Golden Eagle nesting centroids. We measured the frequency and biomass of individual prey, calculated diet diversity indexes, and monitored nestling survivorship at 15 territories in 1971–1981 and 2014–2015. On average, 0.70 of the area within 3 km of nesting centroids burned between 1981 and 2013, and the mean proportion of unburned shrubland decreased from 0.73 in 1979 to 0.22 in 2014. Diets in post-burn years were more diverse and had a lower proportion of some shrub-associated species, such as black-tailed jackrabbits (Lepus californicus) and mountain cottontails (Sylvilagus nuttallii), and a higher proportion of American Coots (Fulica americana), Mallards (Anas platyrhynchos), Piute ground squirrels (Urocitellus mollis), and Rock Pigeons (Columba livia) compared with pre-burn years. A high proportion of waterfowl represented a novel change in Golden Eagle diets, which are typically dominated by mammalian prey. Nestling survivorship was positively associated with the proportion of black-tailed jackrabbits and negatively associated with the proportion of Rock Pigeons in eagle diets. Rock Pigeons are a vector for Trichomonas gallinae, a disease-causing protozoan lethal to young eagles. Nesting attempts were more likely to fail (all young die) in the post-burn period compared with the pre-burn period. Dietary shifts are a common mechanism for predators to cope with landscape change, but shifts away from preferred prey to disease vectors affect nestling survivorship and could lead to population-level effects on productivity.

中文翻译：

---

野火和灌木消失后的金鹰饮食变化对雏鸟的生存产生负面影响

野火和入侵物种已引起北美西部灌木草原景观的广泛变化。退化的灌木丛对捕食者生态和人口统计的自下而上的后果仍然知之甚少。我们使用前后配对设计来研究金鹰 (Aquila chrysaetos) 的饮食和雏鸟生存率在美国爱达荷州西南部发生野火后是否发生了变化。我们评估了 1981 年至 2013 年的烧伤程度以及 1979 年（烧前）和 2014 年（烧后）之间的植被变化，在金鹰筑巢中心 3 公里范围内。我们测量了个体猎物的频率和生物量，计算了饮食多样性指数，并监测了 1971-1981 年和 2014-2015 年在 15 个地区的雏鸟存活率。平均而言，在 1981 年至 2013 年期间，筑巢中心 3 公里范围内有 0.70 个区域被烧毁，未烧毁灌木丛的平均比例从 1979 年的 0.73 下降到 2014 年的 0.22。烧伤后年份的饮食更加多样化，一些灌木相关物种的比例较低，例如黑尾长耳兔 (Lepus californicus) 和山地与燃烧前的年份相比，棉尾鹦鹉 (Sylvilagus nuttallii) 和美洲白帽 (Fulica americana)、野鸭 (Anas platyrhynchos)、Piute 地松鼠 (Urocitellus mollis) 和岩鸽 (Columba livia) 的比例更高。高比例的水禽代表了金鹰饮食的新变化，金鹰饮食通常以哺乳动物猎物为主。雏鸟存活率与黑尾长耳兔的比例呈正相关，与鹰饮食中岩鸽的比例呈负相关。岩鸽是鸡毛滴虫的载体，一种对幼鹰致命的致病原生动物。与燃烧前阶段相比，燃烧后阶段的筑巢尝试更有可能失败（所有幼仔都死亡）。饮食变化是捕食者应对景观变化的常见机制，但从首选猎物到疾病媒介的转变会影响雏鸟的存活率，并可能导致种群水平对生产力的影响。