The Joy of Releasing Penguins

Knowing when a penguin is ready to leave is more art than science. Weight, posture, behaviour, and disposition all factor in. During moulting, the state of the feathers matters too. Miss any of it, and you either send a bird back too soon or keep it longer than necessary.

Mid-moult and looking rough — patchy, fluffy, and not yet waterproof. This Hoiho came in underweight and needed help getting through one of the most physically demanding events of its year.

We do not put our penguins straight back into the ocean. Instead, we release them to a safe location and let them decide when they are ready to swim. Most spend a day getting their bearings, then leave with the colony the following morning. We release about 1km north of our site. Sometimes the penguins beat us back.

Two Hoiho in the enclosure, feathers still coming in, surveying the world from the highest point they can find. Classic penguin behaviour — curious, impatient, and already sizing up the exit.

Of the penguins we care for, 85% are Hoiho, 10% are Little Penguins, and 5% are crested species: Tawaki, Snares, Erect-crested, Royals, or Rockhoppers. The mix shifts with the season.

A crested penguin in care — this season brought both Hoiho and crested species through our doors. Each one comes with its own set of challenges and its own timeline.

This season has been Hoiho and crested penguins. Most Hoiho arrived because they were too light heading into the moult. A penguin can lose around 3kg during that process, so they need to start at 7kg or more to survive it without help. Starvation is, numerically, the leading cause of death in Hoiho.

Found during a monitoring round, tucked into the bush and moulting alone. Not every penguin makes it to us in time. This one did.

Even with clear criteria, we do not always get the timing right. Some birds are desperate to leave before they are ready. Others settle in a little too comfortably and overshoot their target weight. The average stay is three weeks.

Three crested penguins back on solid ground, healthy and together. This is what a good outcome looks like.

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Yesterday, we released the last Hoiho that had come into moult. This morning, on our monitoring rounds, we found another one that needs help.

That is the job. Not for gain. Not for glory.

This article was written for WReNNZ

By Rosalie Goldsworthy, Penguin Rescue