Frozen emperor penguin chick at the Snow Hill Island rookery in Antarctica. Under normal circumstances, living and growing up in these harsh environments are challenging at best. The retreating sea ice further threatens their survival as their existence depends upon it. The rookery is on the sea ice, and its location is a fine balance between providing enough shelter and solid form for the chicks to incubate, hatch and fledge during the winter, and for the ice to retreat enough during the spring/summer for the juveniles to have access to the open water to feed when they are ready. If the ice melts before the chicks have molted from their downy feathers to their adult waterproof feathers, the chicks will drown. This is what likely happened in Halley Bay rookery, also in the Weddell Sea. In 2016 and subsequently in 2017 and 2018, the sea ice broke early. The second largest emperor penguin colony collapsed, with the deaths of all the chicks.
