This time of year is busy for yellow-eyed penguins. They are molting, replacing all of their feathers at once for a brand new set. This is very energetically taxing and because they are no longer waterproof during this time they stay on land for three or four weeks. They can’t forage and find fish so must prepare by eating and eating before hand. They can go from around 5 kg to 7 or 8 kg. However, for reasons only speculated (including low fish stocks and poor water visibility), they sometimes are not able to gain that weight and will starve before their molt is over. This year we are seeing a lot of that, and many people working for a variety of different organizations, including the University (and good friend Mel), are out searching for underweight molters. These underweight birds will go to rehab for a week or two, get fed lots of fish, finish their molt, and be released again. Without this they would likely not survive.
I have had the chance to go with Mel to a few sites in the Catlins and with a DOC ranger to a breeding area on the Otago Peninsula. While there we have been crawling around searching for feathers, the tell-tale sign of a molting penguin. After successfully locating and catching said penguin, we weigh it to make sure it is heavy enough to make it through the next few weeks. Typically a bird weighing less than 6kg, and depending on how far it is into the molt period, we will uplift that individual and bring to rehab. This season this occurred about half the time. The rehab facilities have hit record numbers of patients!
Without the amazing work and all the organizations and rehab centers, think of the penguins that would not survive.