Unraveling the secrets of the Snow Hill emperors | Polarjournal
The emperor penguin colony on Snow Hill Island is the northernmost of the 66 colonies. Although it is frequently visited by expedition ships, little is known about the migrations and feeding behavior of approximately 4,000 breeding pairs. (Photo: Michael Wenger)

Although emperor penguins are considered the most iconic species in Antarctica, knowledge about the largest penguin species is still patchy. This is not least due to the remoteness of the 66 known colonies and the animals’ complex breeding strategy. A British research team now wants to find out more about the animals and has visited the northernmost colony near Snow Hill Island.

Using a drone, many samples of guano and satellite transmitters, Dr. Peter Fretwell, Dr. Norman Ratcliff and PhD student Hugo Guimaro looked into questions about the way of life of the approximately 4,000 breeding pairs of emperor penguins. They were supported by the expedition team from tour operator Quark Expeditions on board its vessel Ultramarine. Where do the animals migrate in search of food for their chicks and afterwards, what do they feed on during the breeding season and, above all, exactly how large is the colony: all basic questions to which there are hardly any answers to date, but which are essential if the animals are to be better protected. After all, Snow Hill Island is the northernmost colony in an area that is very strongly influenced by the effects of climate change. The data collected by the three researchers could provide an insight into what could happen at the other 65 sites in the future.

The methods used by the three researchers, who were accompanied by photographer Neil Ever Osborne for documentation, included taking guano samples for DNA identification of food components. PhD student Hugo Guimaro from the University of Coimbra in Portugal not only wants to collect information about the diet of emperor penguins during the breeding season in the western Weddell Sea, but also gain an overview of the region’s food web. In addition to the genetic data of the emperor penguins’ prey, the samples also contain genetic material of the organisms that were eaten by the prey.

Dr. Norman Ratcliff uses GPS Argo transmitters attached to the backs of 15 animals to investigate where the animals search for and find their food. These transmitters transmit the migration routes practically in real time until the time of moulting. When the animals then change their feathers, the transmitter falls off. Attaching the transmitters was not something he could do on his own, however, and in the end all team members were required to attach the transmitters as quickly and gently as possible. They received support from sea ice specialist Steffen Graupner, who was part of the ship’s team and responsible for measuring the thickness of the sea ice.

One of the most important questions surrounding emperor penguin colonies is how large these aggregations actually are. Due to the remoteness of most colonies, very little data is available. As a result, the information on the total population is only a rough estimate. However, Dr. Peter Fretwell believes that this situation can be improved in the future thanks to the increasing resolution of satellite images. However, in order to be able to calibrate these satellite images and their evaluation, data must first be collected from lower altitudes. To do this, the researcher flew over parts of the colony with a drone and took pictures in which the individual animals can then be counted. AFterwards, the data can be compared with the corresponding satellite images, allowing the population size of the colony to be determined more accurately.

In the future, an artificial intelligence currently under development should make it possible to quickly and efficiently analyze VHR (Very High Resolution) satellite images and thus give a more accurate number of emperor penguins around Antarctica. However, in order to train this AI in the best possible way, some data collection at other locations is still necessary. This means that a number of expedition projects are still to come in order to learn more about the icon of the Antarctic.

Dr Michael Wenger, PolarJournal

Link to the project page at British Antarctic Survey: Snow Hill Emperor Penguin Expedition

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