Grounded iceberg forces emperor penguin chicks to starve on Coulman Island

A massive iceberg that grounded near Coulman Island in July 2025 created a physical barrier for returning emperor penguins, forcing them to scale a steep face and take a longer route to the sea. This delay meant many chicks did not receive enough food, resulting in a 69 percent reduction in live chick counts from 21,242 in 2024 to 6,658 in 2025, according to aerial surveys. The iceberg, which split from a southern ice shelf, stayed lodged until January 2026, increasing the shortest water-to-colony distance from roughly 9.3 km to 14.9 km.

Researchers used 3-D reconstructions from satellite images to map the iceberg’s contours, noting a gentle slope that lured penguins onto a 20-meter drop. While the iceberg has now moved on, scientists caution that warming temperatures may cause more frequent iceberg break-offs that could similarly disrupt penguin breeding cycles. The study was published in Communications Earth & Environment.