Avian tissue sampling following oil pollution events: quantifying impacts and monitoring recovery

Oil pollution is a persistent threat to coastal environments and can cause significant harm to wildlife, particularly aquatic birds. Additionally, shipping rates are increasing across the globe, and while regulations are improving on certain aspects of fuel choice and chemical composition, there is still a growing potential for spills and increased chronic discharge. Existing and planned offshore oil production adds further complexity to oil pollution risks worldwide. Despite this, there is little guidance for wildlife responders on what avian tissues to sample, how to preserve them, and how many samples are needed in the immediate aftermath of a spill. We provide a practical guide for responders and researchers to assist with sample collection, preservation, logistics, and relevant laboratory analyses to address project goals. We also highlight the value of timely sample collection, especially in time-sensitive situations. We emphasize laboratory analyses that provide individual-level exposure metrics that cannot be obtained from population-level information alone. These metrics are helpful for understanding the spill’s immediate impact, supporting damage assessments, and informing legal actions, if applicable. We also provide guidance on long-term monitoring plans to evaluate the potential inter-annual impacts of spills on marine bird populations. Sampling techniques are reviewed for assessment of polycyclic aromatic compounds (PACs), trace metals, epigenetics, toxicogenomics, foraging ecology, endocrine disruption, and hemolytic anemia. Flowcharts are included to assist with quick decision-making while considering key factors such as Indigenous concerns, species selection, and seasonality.