Globally, evaluation of population trends is the most pressing research need for many species of conservation concern. Road counts for birds of prey are useful for monitoring long‐term population trends and examining year‐to‐year variations in abundance. We examined data from 2155 road surveys conducted from 2001 to 2018 by community scientists who recorded > 85 000 individuals of 14 species of raptors while participating in the Pennsylvania Winter Raptor Survey, in Pennsylvania, USA. We estimated abundance and population growth rates while accounting for observation error by using dynamic Bayesian state‐space models. Model estimates indicated that counts of wintering Bald Eagles Haliaeetus leucocephalus, Red‐shouldered Hawks Buteo lineatus and Black Vulture Coragyps atratus increased over the course of the study. Counts of Rough‐legged Buzzard Buteo lagopus, Red‐tailed Hawk Buteo jamaicensis, Northern Harrier Circus hudsonius, Turkey Vulture Cathartes aura and American Kestrel Falco sparverius varied more (CV > 5.0) over the duration of the study than other species did. Higher winter temperatures were associated with increases in counts of species whose local populations are partially migratory (American Kestrel and Red‐tailed Hawk), and with lower counts of a long‐distance arctic migrant – Rough‐legged Buzzard. Counts of these species were therefore correlated such that more American Kestrels and Red‐tailed Hawks were counted during years when Rough‐legged Buzzards were less frequently seen. Generally, the number of individuals counted declined as survey speed increased. A general rule for road counts therefore seems to be ‘slower is better’, consistent with past recommendations that observers travel at a speed < 40 km/h during road counts. Our study highlights the utility of road surveys and advances analytical approaches to monitor raptors.

中文翻译：

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年度温度波动和调查速度会影响冬季猛禽的行进次数

在全球范围内，对种群趋势的评估是对许多保护物种的最紧迫的研究需求。猛禽的路数可用于监测长期种群趋势并检查数量逐年变化。我们检查了2001年至2018年期间由社区科学家进行的2155次道路调查的数据，这些科学家在参加美国宾夕法尼亚州的宾夕法尼亚州冬季猛禽调查时记录了14种猛禽的85,000多人。我们通过使用动态贝叶斯状态空间模型估算了丰度和人口增长率，同时考虑了观测误差。模型估计表明，越冬的秃头鹰Haliaeetus leucocephalus，红肩鹰Buteo lineatus和黑雕的数量在整个研究过程中，孔雀鱼增加了。粗足的秃鹰But，红尾鹰But，北Har马戏团，土耳其火鸡兀Cat Cathartes aura和美国红est Falco sparverius的计数在研究期间，其变化比其他物种变化更大（CV> 5.0）。较高的冬季温度与当地人口部分迁徙的物种数量增加（美洲红est和红尾鹰）有关，而与长距离北极迁徙者（粗足B）的数量减少有关。因此，这些物种的数量具有相关性，因此，在不经常看到粗腿秃鹰的年份中，有更多的美国Kestrels和红尾鹰被计数。通常，随着调查速度的提高，被统计的人数有所下降。因此，道路盘点的一般规则似乎是“越慢越好”，这与以往的建议一致，即观察者在道路盘点期间以<40 km / h的速度行驶。