---
title: "Erect-crested penguins fell 40% on New Zealand’s Antipodes Islands; the tiny Bountys held steady for 25 years"
url: https://badiyaa.com/erect-crested-penguins-antipodes-bounty-islands/
published: 2026-11-15T14:30:00+00:00
modified: 2026-11-15T14:30:00+00:00
section: Science
publisher: Badiyaa
---

# Erect-crested penguins fell 40% on New Zealand’s Antipodes Islands; the tiny Bountys held steady for 25 years

Erect-crested penguins on New Zealand's Antipodes Islands fell over 40% since 1995 while the tiny Bounty Islands stayed stable, a drone census finds.

New Zealand’s erect-crested penguins live on just two remote island groups, and a drone census has found them heading in opposite directions. On the Antipodes Islands, breeding numbers have fallen by more than 40% since 1995. On the Bounty Islands, a cluster of rocks 40 times smaller, the population has barely moved in at least 25 years and is now almost as large.

The study, published in PLOS ONE, was led by Thomas Mattern of the Tawaki Project at the University of Otago, with the Antarctic Research Trust and the Global Penguin Society. Drone flights between 2022 and 2024 photographed every breeding colony on both island groups, giving the first full count of the species.

## The numbers

The Bounty Islands, just 50 hectares of land, hold about 27,800 breeding pairs. The Antipodes Islands, long treated as the stronghold, hold about 29,800.

Run the arithmetic and the contrast sharpens. Dividing 27,800 pairs by 50 hectares gives about 556 pairs per hectare on the Bountys. The Antipodes are roughly 40 times larger, about 2,000 hectares, so 29,800 pairs works out to about 15 per hectare. Together the two counts add up to about 57,600 pairs, a quarter of the 230,000 pairs estimated in the late 1970s, a figure whose accuracy has since been questioned, according to the [erect-crested penguin species account](https://en.wikipedia.org/wiki/Erect-crested_penguin).

“The results overturn a long-standing assumption,” Mattern said in a University of Otago statement.

## Why the Antipodes birds are losing ground

The researchers point to several pressures that stack on each other. Skuas, native seabirds that take penguin eggs and chicks, do more damage as colonies shrink, because small groups cannot defend themselves as well as big ones. Smaller colonies then lose more chicks and split further.

Co-author Klemens Pütz of the Antarctic Research Trust links that to a second collapse. Eastern rockhopper penguins on the Antipodes fell to fewer than 1,000 breeding pairs after a steep 20th-century decline. “As Rockhoppers disappeared, skuas may have turned to Erect-crested penguin eggs and chicks instead,” Pütz said.

Fiercer storms have also triggered landslides that break up colonies. And the two populations winter in different waters: Antipodes birds travel far south into the Antarctic Polar Frontal Zone, while Bounty birds stay closer to home, in more sheltered seas that may offer more food.

## Schrödinger’s penguin

The team calls the situation “Schrödinger’s Penguin,” after the thought experiment in which a boxed cat is both alive and dead until someone looks. Here, Mattern argues, the species looked like a single case from a distance, and only opening the box revealed two states: stable on one island group, falling on the other.

That matters for its legal and conservation status. The erect-crested penguin is one of four penguin species listed as Endangered on the IUCN Red List, a ranking built on inflated 1970s estimates. Averaging both populations could improve the global ranking to Vulnerable, which the authors warn would hide the Antipodes decline and leave the Bounty birds, likely the last secure stronghold, exposed to industrial fishing nearby.

## Limits

The causes are proposed, not proven: the survey measures how many birds there are, not why they changed. The historical comparisons rely on older counts made with different methods.

The finding joins other recent seabird surprises, from [Gus the emperor penguin’s 3,500 km swim to Western Australia](https://badiyaa.com/gus-emperor-penguin-western-australia/) to the [Midway Atoll albatross pair raising chicks season after season](https://badiyaa.com/george-geraldine-short-tailed-albatross-midway/). “A single, ostensibly improved threat ranking is like putting the lid back on Schrödinger’s box,” Mattern said.

## Further reading

- [Wikipedia: Erect-crested penguin](https://en.wikipedia.org/wiki/Erect-crested_penguin)

*Image: John Barkla, CC BY 4.0 via Wikimedia Commons*

*This article was produced with AI assistance and reviewed by our Editorial Desk. [How we work](https://badiyaa.com/editorial-policy/).*