Kaplan-Meier and Cox survival analysis of fuel oil-contaminated Black Sea birds reveals potential conservation measures

Tens of thousands of seabirds and coastal animals suffer from exposure to oily substances each year from oil product spills. Methods of bird assistance primarily include catching birds, removing contaminants from their feathers, and rehabilitation after laundering. Based on our practical experience in the treatment of birds contaminated with fuel oil, which was spilled into the Black Sea and the coast of the Krasnodar Territory as a result of an accident involving two tankers carrying 9200 tons of fuel oil, here we analyze the effectiveness of the traditional technology of cleaning birds with potato starch, followed by washing with detergents. Additionally, we collected dynamic data and applied Kaplan-Meier and Cox methods for stratification of non-survival risks in Black Sea bird species after washing and rehabilitation, respectively. Based on our experimental results and analysis, we consider the applicability of preventive measures to conserve bird populations, such as sound and kinetic deterrence. The conventional cleaning process of fuel-oil contaminated Black Sea birds is not always effective for some bird species, and the analysis of their survival rates using Kaplan-Meier and Cox methods reveals sound and kinetic deterrents as potential conservation measures.