Taking the pulse of the world's raptors — A systematic quantitative review of wildlife rehabilitation centre admissions

Abstract

Human activities, including urban expansion, persecution, and energy and transportation infrastructure, contribute to global wildlife declines. Understanding wildlife mortality and morbidity is crucial for conservation, especially for bioindicator species such as raptors. However, causes of raptor mortality and morbidity remain poorly understood on a global scale. Analysing 147,422 wildlife rehabilitation centre (WRC) admissions from 38 sources containing admissions records from 1989 to 2023, we conducted a systematic quantitative review of raptor admission causes for 148 species globally. Raptor admissions increased over time, with owls (34.3%), falcons (23.7%), and buteo hawks (22%) being the most frequently admitted taxonomic groups. Most admissions were due to unknown causes (40.7%), followed by human-related (39.1%) and natural causes (20.2%). The leading human-related causes were unspecified trauma (18.5%), vehicle collisions (14.1%), and electrocution or gas flare incidents (7.4%). Factors including taxonomic group, body mass, feeding guild, threat status, country GDP per capita, and continent significantly predicted admission type (human vs. natural). Mortality probabilities were 60% for human-related admissions and 19% for natural causes. Wind turbine collisions and electrocution or gas flares resulted in the highest mortality rates (98% and 92%, respectively), while eagles and New World Vultures faced the highest overall mortality probabilities following admission (56% and 55%, respectively). Our findings emphasise the need for comprehensive conservation strategies that address human-induced threats, particularly as the global green energy transition advances. Mitigating risks associated with future infrastructure development, including onshore wind turbines, powerlines, and roadways, is crucial for raptor conservation in an anthropogenic world.