Declining juvenile survival of Adelie penguins in Antarctica

As summer sea ice around Antarctica reaches historical lows, quantifying the demographic response of polar species to such environmental changes becomes critical. To achieve this, synthesizing results from across species' ranges and elucidating the environmental factors driving population dynamics are key. Adelie penguins are considered reliable indicators of changes in Antarctica but the pathways through which sea ice and other environmental factors shape their population dynamics are still unclear, especially for the juvenile stage. Using a 17-year dataset of electronically tagged Adelie penguins from Adelie Land (Antarctica), we found that juvenile survival probability was most impacted by sea ice concentration near their natal colony right after fledging, with lower ice concentrations detrimental to survival. Importantly, we found that juvenile survival declined by 32% from 2007 to 2020, mirroring trends at other distant colonies. The emergence of similar patterns at opposite ends of the continent may be an early signal for shifts in population trends expected from climate change.