“…and today we’re talking about little bird blue, but more on that later.”
As seasons change, so do many animals. New coats, sloughed skin, fresh molts–even humans don’t wear white after labor day. For most, it’s a gradual process that can be a challenge, but makes way for growth. For some, it can be dangerous, as the cumbersome metamorphosis leaves animals sluggish and vulnerable. But for the little blue penguin, the necessary process of molting can be downright catastrophic in Life, Death and Taxonomy.
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com.
Height of the Little Blue Penguin
The Little Blue Penguin (Eudyptula minor) stands 13 inches (33 cm) tall. How many objects fit into the penguin’s height (if the object is shorter) or how many penguins fit into the object’s height/length (if the object is taller)?
a) The height of a New Zealand paua shell
A large New Zealand paua (Haliotis iris) shell, common along the penguin’s coastal habitat, measures about 18 cm (7.1 inches) in length, per marine biology data.
b) The length of a Māori taiaha spear
A traditional Māori taiaha, a wooden weapon used in New Zealand, measures about 150 cm (59 inches) long, based on ethnographic records.
c) The height of a yellow-eyed penguin chick
A yellow-eyed penguin (Megadyptes antipodes) chick, also from New Zealand, stands about 25 cm (9.8 inches) tall at fledging, per wildlife data.
Question: How many fit into each height comparison?
A) 3.8 New Zealand paua shells go into the height of a Little Blue Penguin
B) 4.5 Little Blue Penguins go into the length of a Māori taiaha spear
C) 2.3 chicks go into the height of a Little Blue Penguin
Weight of the Little Blue Penguin
The Little Blue Penguin weighs 3 pounds (1.36 kg). How many objects fit into the penguin’s weight (if the object is lighter) or how many penguins fit into the object’s weight (if the object is heavier)?
a) The weight of a kina sea urchin
A kina sea urchin (Evechinus chloroticus), a key food for New Zealand penguins, weighs about 0.5 pounds (0.23 kg) for a large adult, per marine biology data.
b) The weight of a pounamu carving
A small pounamu (greenstone) pendant, a traditional Māori carving from New Zealand’s South Island, weighs about 100 grams (0.1 kg or 0.22 pounds), per cultural artifact records.
c) The weight of a New Zealand fur seal pup
A newborn New Zealand fur seal (Arctocephalus forsteri) pup, found on the same coasts, weighs about 8 pounds (3.6 kg), per wildlife data.
Question: How many fit into each weight comparison?
A) 5.9 kina sea urchins go into the weight of a Little Blue Penguin
B) 15.6 pounamu carvings go into the weight of a Little Blue Penguin
C) 1.6 Little Blue Penguins go into the weight of a New Zealand fur seal pup
Major Fact: A Kororā Catastrophe
Little Penguins undergo a unique and dramatic annual event called the catastrophic moult.
What is a Catastrophic Molt?
Unlike most birds that replace feathers gradually, little penguins undergo a complete, simultaneous feather replacement over 2 to 3 weeks.
It’s called “catastrophic” because:
- All old feathers fall out at once, leaving the penguin temporarily bald and vulnerable.
- The penguin cannot swim or hunt because its plumage is no longer waterproof.
Why is the Molt So Intense?
Waterproofing is critical: Penguins rely on dense, overlapping feathers for insulation and buoyancy in cold waters. A patchy coat would cause hypothermia or drowning.
Energy demands are massive: Growing an entire new feather coat requires up to 50% more energy than normal. Little penguins double their body weight (from ~1 kg to ~2 kg) in the weeks before moulting by gorging on fish and krill.
The Molt Process
- Pre-moult fattening (2–6 weeks): Penguins come ashore and eat voraciously, building fat reserves.
- Onshore fasting (13–20 days): They hide in burrows or rocky crevices, unable to enter water. Old feathers loosen and fall out in clumps.
- New feather growth: Pin feathers (blood-filled quills) emerge, then unfurl into sleek, waterproof plumage.
- Return to sea: Once fully feathered, they waddle back to the ocean, often within hours.
Moult Plasticity
In a 2015–2016 Phillip Island study, molt started ~9.6 days earlier in 2016 (Feb 15 vs. Feb 24), with year as the sole predictor of start date. Duration was similar (median 18.0 d in 2015, 17.5 d in 2016) and slightly shortened with later starts (~58 min/day delay). Daily mass loss increased with longer molt and higher starting mass. Prey availability likely drives molt timing and pre-molt fattening; molt plasticity enhances survival.