Comparing non-breeding distribution and behavior of red-legged kittiwakes from two geographically distant colonies.

Knowledge of non-breeding distributions is a crucial component to seabird conservation, as conditions during the non-breeding period can play an important role in regulating seabird populations. Specifically, if seabirds from different colonies share the same wintering grounds, conditions in that shared region could have a widespread impact on multiple breeding populations. Red-legged kittiwakes (Rissa brevirostris) are endemic to the Bering Sea and may be especially susceptible to effects of climate change due to a restricted breeding range, small population size, and specialized diet. To examine whether red-legged kittiwakes from different breeding colonies overlapped in winter distribution and activity patterns, we used geolocation loggers to simultaneously track individuals from the two largest red-legged kittiwake breeding colonies in Alaska (separated by over 1000 km) during two consecutive non-breeding periods. We found that non-breeding activity patterns were generally similar between birds originating from the two colonies, but birds employed different migratory strategies during the early winter. Kittiwakes from Buldir Island in the western Aleutian Islands left the colony in September and immediately headed west, spending October through December around the Sea of Okhotsk and the Kuril Islands. In contrast, birds from St. George Island in the Pribilof Islands remained in the eastern Bering Sea or around the eastern Aleutian Islands for a couple months before traveling farther west. During late winter however, from January through March, birds from both colonies converged south of Kamchatka and east of the Kuril Islands over the Kuril-Kamchatka Trench and in the Western Subarctic Gyre before returning to their respective colonies in the spring. This late winter overlap in distributions along the Kuril-Kamchatka Trench suggests the region is a winter hotspot for red-legged kittiwakes and highlights the importance of this region for the global kittiwake population.

Ecosystem response persists after a prolonged marine heatwave.

Some of the longest and most comprehensive marine ecosystem monitoring programs were established in the Gulf of Alaska following the environmental disaster of the Exxon Valdez oil spill over 30 years ago. These monitoring programs have been successful in assessing recovery from oil spill impacts, and their continuation decades later has now provided an unparalleled assessment of ecosystem responses to another newly emerging global threat, marine heatwaves. The 2014-2016 northeast Pacific marine heatwave (PMH) in the Gulf of Alaska was the longest lasting heatwave globally over the past decade, with some cooling, but also continued warm conditions through 2019. Our analysis of 187 time series from primary production to commercial fisheries and nearshore intertidal to offshore oceanic domains demonstrate abrupt changes across trophic levels, with many responses persisting up to at least 5 years after the onset of the heatwave. Furthermore, our suite of metrics showed novel community-level groupings relative to at least a decade prior to the heatwave. Given anticipated increases in marine heatwaves under current climate projections, it remains uncertain when or if the Gulf of Alaska ecosystem will return to a pre-PMH state.