Satellite Guano Color Reveals Adélie Penguin Diet Shift Amid Sea Ice Loss

A team of scientists has used thousands of NASA Landsat images to track the color of Adélie penguin guano across Antarctica, a proxy for the birds’ diet. The study shows that colonies with more sea ice feed on small fish, while those in ice‑free areas rely more on krill. The shift is linked to the rapid sea ice decline since the 2010s, which reduces fish availability and results in lighter chicks that are less likely to survive. Populations in fish‑rich colonies remain stable or grow, whereas those feeding mainly on krill have declined over recent decades. The research demonstrates how satellite data can monitor wildlife diets in remote regions and highlights the broader impact of climate change on the Southern Ocean food web.