Tuesday, January 20, 2026

 

A two-week leap in breeding: Antarctic penguins’ striking climate adaptation




University of Oxford
Gentoo colony at Neko Harbour 

image: 

Gentoo colony at Neko Harbour (ES: Puerto Neko). An egg is visible at one of the nests. Credit Ignacio Juarez Martinez

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Credit: Ignacio Juarez Martinez


More images available via the link in the notes section

 

A decade-long study led by Penguin Watch1, at the University of Oxford and Oxford Brookes University, has uncovered a record shift in the breeding season of Antarctic penguins, likely in response to climate change. These changes threaten to disrupt penguins’ access to food and increase interspecies competition. The results have been published today (20 January - World Penguin Awareness Day) in the Journal of Animal Ecology.

Lead author Dr Ignacio Juarez Martínez (University of Oxford/Oxford Brookes University) said: “Our results indicate that there will likely be ‘winners and losers of climate change’ for these penguin species. Specifically, the increasingly subpolar conditions of the Antarctic Peninsula likely favour generalists like Gentoos at the expense of polar specialists like the krill-specialist Chinstraps and the ice-specialist Adélies. Penguins play a key role in Antarctic food chains, and losing penguin diversity increases the risk of broad ecosystem collapse.’

The researchers examined changes in the timing of penguin breeding between 2012 and 2022, specifically their “settlement” at the colony, the first date at which penguins continuously occupied a nesting zone. The three species of penguins studied were the Adélie (Pygoscelis adeliae), Chinstrap (P. antarcticus) and Gentoo (P. papua), with colony sizes ranging from a dozen to up to hundreds of thousands of nests. They used evidence from 77 time-lapse cameras overlooking 37 colonies in Antarctica and some sub-Antarctic islands, which ensures conclusions are relevant to species as a whole and not just specific populations.

The results demonstrated that the timing of the breeding season for all three species advanced at record rates. Gentoo penguins showed the greatest change, with an average advance of 13 days per decade (up to 24 days in some colonies). This represents the fastest change in phenology recorded in any bird – and possibly any vertebrate – to date. Adélie and Chinstrap penguins also advanced their breeding by an average of 10 days.

Senior author Professor Tom Hart (Oxford Brookes University and founder of Penguin Watch) said: “Ecologists are good at counting populations to show trends, but often the early warnings of decline can be found in the behavioural change of animals, which can be very hard to monitor. The idea of this whole monitoring network is to put something in place that does both; monitoring populations and their behavioural responses to threats. This study proves the benefits of monitoring animals at a landscape level.”

These record shifts are happening in relation to changes in the environment including sea-ice, productivity and temperature. Each monitoring camera was equipped with a thermometer, enabling researchers to also track the temperature changes at colonies. The data revealed that colony locations are warming up four times faster (0.3ºC/year) than the Antarctic average (0.07ºC/year), making them one of the fastest-warming habitats on Earth.

Though statistical models suggest that temperature appears to be one of the dominant drivers of the observed shifts in breeding season, it remains unclear whether the changes reflect an adaptive response or not, risking a potential mismatch with other ecological factors such as prey availability. Even in the best-case scenario, it is unclear how much more elasticity these species will be capable of displaying if temperatures keep rising at the current rate.

Co-author Dr Fiona Jones (University of Oxford) added: “As penguins are considered 'a bellwether of climate change', the results of this study have implications for species across the planet. Further monitoring is needed to understand whether this record advance in the breeding seasons of these penguin species is impacting their breeding success.”

This research was also made possible thanks to international collaborators in the UK (University of Oxford, Oxford Brookes University, British Antarctic Survey), US (Stony Brook University, NOAA) and Argentina (CADIC-CONICET). The researchers would also like to thank the John Ellerman Foundation, Save our Seas Foundation, Quark Expeditions and the UK Government's Darwin Plus funding scheme for their support.

Notes to editors:

For media enquiries and interview requests, contact Ignacio Juarez at ijuarez.research@gmail.com and Tom Hart at t.hart@brookes.ac.uk

The study ‘Record phenological responses to climate change in three sympatric penguin species’ will be published in Journal of Animal Ecology at 05:01 AM (GMT), Tuesday 20 January, 2026 at doi.org/10.1111/1365-2656.70201. To view a copy of the study before this under embargo, contact ijuarez.research@gmail.com

Images available to use in articles can be found here Outreach Images IJM. These are for editorial purposes relating to the press release ONLY and MUST be credited. They MUST NOT be sold on to third parties.

About the University of Oxford

Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the tenth year running, and ​number 3 in the QS World Rankings 2024. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer. Oxford is world-famous for research and teaching excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research alongside our personalised approach to teaching sparks imaginative and inventive insights and solutions. Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 300 new companies since 1988. Over a third of these companies have been created in the past five years. The university is a catalyst for prosperity in Oxfordshire and the United Kingdom, contributing around £16.9 billion to the UK economy in 2021/22, and supports more than 90,400 full time jobs.

About Oxford Brookes University
www.brookes.ac.uk

Oxford Brookes is one of the UK's leading modern universities, and is amongst the world’s top universities in 23 subject areas. Oxford Brookes prides itself as a diverse and inclusive university with students and staff from over 170 countries and it enjoys an international reputation for teaching excellence as well as strong links with business, industry and the public sector.

1. Penguin Watch project
https://www.polarsentinels.org/projects/penguin-watch

Penguin Watch is the largest penguin monitoring project in the Southern Ocean. Initiated at the University of Oxford in 2009 and currently hosted at Oxford Brookes University, it focuses on disentangling the confounded threats faced by penguins by harnessing time-lapse cameras to monitor penguin colonies year-round.

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