Climate: a cuddly toy to monitor the state of health of penguins

The Southern Ocean plays a major role in the regulation of the world's climate. From an ecological viewpoint it is one of the most productive regions of our planet. It harbours, among other things, the largest communities of seabirds, whose state of health depends directly on the resources of the sea. The large decrease in numbers in the majority of these bird populations suggests a major disturbance in this ecosystem. In order to assess the vulnerability of the Southern Ocean with respect to environmental changes, the PICASO project team has focused its attention on penguins in particular. Aided by a remote-operated vehicle (rover) "disguised" as a penguin chick, the scientists are studying their reproduction and survival on the scale of the population and on each individual bird. The aim is to obtain a better understanding of the overall state of health of this ocean.

The PICASO project team has been working on this theme for a long time, playing a leading role in the development of methods for studying wildlife while minimising disturbance of the populations. The particular anatomy of penguins' legs means that it is impossible to place a band (or ring) on them. The scientists therefore chose to tag the birds with flipper bands, enabling them to be monitored from a distance. In 2011 however, researchers demonstrated that this system hindered the penguins' movements in water, which risked compromising their survival. They therefore turned to an alternative: the transponder, i.e. an electronic tag inserted under the skin. The transponder does not create any discomfort for the bird but it does have a technical limitation, namely the very short range of the Radio Frequency IDentification (RFID) signal it emits, which is about 60 cm. To locate a penguin, the researchers had to walk through the colony carrying a hand-held RFID reader and risking disturbing the birds.

Human intrusion in the natural environment of the penguins effectively results in an increase in their heart rate and disrupts the structure of their colonies. The scientific team therefore had the idea of replacing humans by remote-operated vehicles equipped with RFID readers, the first of these being a former rover donated by the Mine Clearing Department of the French Ministry of the Interior. They experimented this system on king penguins - which have the reputation of defending their territory - on the Ile de la Possession (Possession Island) in the Crozet Archipelago (Sub-Antarctic). The penguins attacked the moving rovers with their beaks and flippers, but ignored them as soon as they came to a standstill. The study continued in the colony of emperor penguins situated near the French Dumont d'Urville station in Adélie Land. The reaction of the emperor penguins was to retreat when the rover approached. The researchers then had the idea of camouflaging the rover by placing a fake penguin chick on top of it. The rover could thus approach the penguins without frightening them and disrupting their organisation. The penguins even tried to communicate with it.

The value of this "disguised" remotely controlled device has just been proven by the multidisciplinary Hubert Curien Institute and the Scientific Centre of Monaco. It will thus enable the research to be conducted in a more ethical manner while at the same time avoiding the scientific biases associated with the disturbance of the birds. These results were published in the review Nature Methods in early November.

An original and multidisciplinary project

The initial postulate of the PICASO project is that environmental changes do not affect all individuals in the same way. In the researchers' opinion, the history of each bird could influence its capacity to adapt in terms of reproductive success and survival. This is an innovative approach because individual variability is rarely addressed in this type of research. Thanks to this technology, it was possible to conduct this study on the scale of both the individual and the population. Another originality of the project is that it studies "immunocompetence", that is to say the response of the penguins to oxidative stress and ageing, in order to judge the impact of the environmental conditions on the organisms. Lastly, by adopting a multidisciplinary and integrative approach, the PICASO project has allowed the development of global mathematical models that aid the understanding of the links between environmental changes and the trajectories of these populations. In other words, these are models for predicting the evolution of the biological component of southern (austral) ecosystems in response to major climate changes.

Find out more

The PICASO project brings together teams from the Alsace and Languedoc-Roussillon delegations of the CNRS (French National Scientific Research Centre), the Paris VI (Pierre et Marie Curie) University, the Oslo-Norway University's Centre for Ecological and Evolutionary Synthesis and the Phillip Island Nature Parks in Australia. Coordinated by Yvon Le Maho, this project was funded by ANR in 2010. It is also supported by the Paul-Emile Victor Polar Institute and the Total Corporate Foundation.