The breeding population of Peregrine Falcon <i>Falco peregrinus</i> in the United Kingdom, Isle of Man and Channel Islands in 2014

<b>Capsule:</b> Overall numbers of Peregrines are higher than previously recorded, due primarily to the growth of lowland populations, despite declines in many upland areas. <b>Aims:</b> To estimate the breeding population of Peregrines, and changes in this population over time, as well as to relate variation in trends and observed breeding success to variation in region, breeding site type and other ecological influences. <b>Methods:</b> Two types of survey methods were used. Site-based visits focussed on locations where Peregrines were known to have bred previously, while area-based searches aimed to find all Peregrines breeding in randomly chosen 5 km × 5 km squares. Findings from each method were used to estimate population size in different parts of the survey area. Breeding outcome and site type were assessed for most of the pairs found during either survey. <b>Results:</b> In 2014, the breeding population of Peregrines in the UK, Isle of Man and Channel Islands was estimated at 1769 pairs. This is 22% larger than the population estimate from the previous survey in 2002. Most of this increase is accounted for by increases in lowland England. Populations in some upland areas have declined. <b>Conclusions:</b> The gap between the fortunes of lowland and upland Peregrines has continued to grow, along with the overall UK population. Likely reasons for the continued success of Peregrines in the lowlands include increasing uptake of breeding sites on human structures, abundant availability of prey in many lowland situations and, in many areas, a relative lack of conflict with humans. Factors likely to be limiting upland Peregrine populations vary between different regions, and include ongoing illegal killing and deliberate disturbance, and food supply.**概要**：整体游隼（Peregrines）种群数量较此前记录更高，这主要得益于低地种群的增长，尽管许多高地地区的种群出现下降。 **研究目标**：本研究旨在估算游隼的繁殖种群数量及其随时间的变化，并将种群趋势与观测到的繁殖成功率的差异与区域、繁殖位点类型及其他生态影响因素的差异关联起来。 **研究方法**：本研究采用两类调查方法：基于位点的走访聚焦于此前已知有游隼繁殖的区域，而基于区域的搜寻则旨在在随机选取的5千米×5千米样方内找到所有繁殖的游隼。通过两种方法的调查结果，可估算研究区域不同片区的种群规模。针对两类调查中发现的绝大多数繁殖对，均对其繁殖结果与位点类型进行了评估。 **研究结果**：2014年，英国、马恩岛与海峡群岛的游隼繁殖种群数量估算为1769对，较2002年上次调查的种群估算值提升了22%。此次增长主要源于英格兰低地地区的种群扩张，而部分高地地区的种群则出现了下降。 **研究结论**：随着英国整体种群规模的扩张，低地与高地游隼的种群境况差距持续扩大。游隼在低地地区持续繁盛的潜在原因包括：人类建筑上的繁殖位点被愈发频繁地利用、多数低地区域猎物资源充足，且在多数地区与人类的冲突相对较少。限制高地游隼种群的潜在因素因区域而异，包括持续的非法猎杀与人为刻意干扰，以及食物供给不足。