Global assessment of marine plastic exposure risk for oceanic birds.

Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Flying south: Foraging locations of the Hutton's shearwater (Puffinus huttoni) revealed by Time-Depth Recorders and GPS tracking.

The Hutton's shearwater Puffinus huttoni is an endangered seabird endemic to Kaikoura, New Zealand, but the spatial and temporal aspects of its at-sea foraging behavior are not well known.To identify foraging areas and estimate trip durations, we deployed Global Positioning Systems (GPS) devices and Time-Depth Recorders (TDR) on 26 adult Hutton's shearwaters during the chick-rearing period in 2017 and 2018.We found Hutton's shearwaters traveled much further from their breeding grounds at Kaikoura than previously considered, with most individuals foraging in coastal and oceanic areas 125-365 km south and near Banks Peninsula. Trip durations varied from 1 to 15 days (mean = 5 days), and total track lengths varied from 264 to 2,157 km (mean = 1092.9 km).Although some diving occurred in near-shore waters near the breeding colony, most foraging was concentrated in four regions south of Kaikoura. Dive durations averaged 23.2 s (range 8.1 to 71.3 s) and dive depths averaged 7.1 m (range 1.5 to 30 m). Foraging locations had higher chlorophyll a levels and shallower water depths than nonforaging locations. Birds did not feed at night, but tended to raft in areas with deeper water than foraging locations.Mapping the spatial and temporal distribution of Hutton's shearwaters at sea will be fundamental to their conservation, as it can reveal potential areas of overlap with fisheries and other industrial users of the marine environment.