Kittiwake chick (IMAGE) McGill University Caption Once a kittiwake chick hatches, the parents have to forage to feed their offspring, sometimes flying as far as 250 km in a day. In the process they lose 10% of their body weight, mostly by losing fat, and increase their breast muscle size. New research suggests that, in the process, they may also be improving their muscle structure. Credit IMAGE CREDIT: Kristen Lalla Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.