What is it about?
The Erect-crested penguin breeds on only two remote island groups in New Zealand’s subantarctic: the Bounty Islands and the Antipodes Islands. Between 2022 and 2025 we surveyed both island groups with drones, which gave us the first reliable full count of the species' world population. The two populations are going in opposite directions. The Bounty Islands population has stayed stable for over 25 years at about 27,800 breeding pairs. The Antipodes population has fallen by more than 40% since the mid-1990s and is now about 29,800 pairs. On the Antipodes, colonies with nests packed closely together are holding steady, while sparser colonies are declining steeply. This pattern fits with egg and chick predation by Brown Skuas, which are absent from the Bounty Islands, although differences in marine ecology and the impact of ocean warming between the two populations likely also play another important role.
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Photo by Martin Wettstein on Unsplash
Why is it important?
The IUCN Red List assesses a species’ global population as one unit. Added together, the two island populations look stable enough to move the species from “Endangered” to the less severe “Vulnerable”. That total would hide a substantial decline on the Antipodes. A downlisting could also be misread as grounds for less scrutiny of fisheries around the Bounty Islands at a time of broader deregulation. Our results, together with the uncertainty in the long-term trend, support keeping the species listed as "Endangered". More generally, threat assessments for species found at only a few sites need to look at what is happening at each site.
Perspectives
How do you get people to care about a penguin that is doing fine and in trouble at the same time? That is the conundrum at the heart of this paper. The Erect-crested penguin has been listed as Endangered for 25 years, yet it has been largely ignored. Until our surveys, nobody had properly counted the main population in decades. It took an independent group, the Tawaki Project, backed by overseas philanthropic funding, to find out what was happening. That says a lot about how precarious things are for species that sit outside public awareness. If a penguin can go unchecked this long, it is hard to know what else we are missing.
Thomas Mattern
Global Penguin Society
Read the Original
This page is a summary of: Schrödinger’s Penguin? Divergent population trajectories and the challenge of assessing the threat status of the Erect-crested penguin, PLOS One, October 2026, PLOS,
DOI: 10.1371/journal.pone.0359075.
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