Tracking Penguin Colonies Through Their Droppings

When most people think of Antarctica, they tend to think of penguins. Antarctica’s great size and the harshness of its coastline has made it difficult for researchers studying penguins to accurately estimate how many of them there are in the Antarctic. However, with the help of satellites, researchers can now track colonies of penguins and find previously unknown groups by imaging their guano.

Researchers are using Landsat 7 satellite imagery on Antarctica’s penguin population and estimating their numbers based on the large guano stains left behind. Since researchers can’t possibly get to every penguin colony on the continent, they came up with the idea of using satellites to track the most obvious marker of a penguin colony- their poop.

From satellites and field research, scientists have been able to come up with unique ways to track penguin groups as they move and grow in this harsh region. New colonies of penguins, larger than most found on the Antarctic continent, have been found off the coast on a series of islands named the Danger Islands. Difficult to reach because of unstable sea ice, satellites are able to see the penguin colonies and have the images confirmed by researchers familiar with the areas in question. Using these methods, thousands of new penguins have been added to the Antarctic penguin population in recent years. Through the use of Landsat 7 imagery, researchers have counted an additional 166,000 penguins on Brash Island, 23,000 on Earle Island, and 7,000 on Darwin Island.

Detection of penguin guano on island in the Antarctic. Image: NASA using Landsat 7 imagery.

Detection of penguin guano on island in the Antarctic. Image: NASA using Landsat 7 imagery.

Satellite images that are looking for signs of penguins will show pinker areas that have been covered in penguin guano.   Bare rocks don’t appear to have that color naturally, making it a bit easier for scientists to determine if there is a group of penguins living nearby. Using color data from areas researchers have been to and tracked penguins, they are able to teach the satellite image to analyze new locations for those particular guano colors. A computer algorithm matches areas on remote islands with known ares of penguin colonies on visited islands. This allows the image analysis to make an educated guess on where penguin colonies may be, without ever having to send a researcher into a dangerous area of the continent.  All of the data on penguin colonies from Landsat 7 imagery analysis is deposited into the open access MAPPPD (Mapping Application for Penguin Populations and Projected Dynamics).

NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey and calculations from Lynch, H. J., & Schwaller, M. R. (2014).

NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey and calculations from Lynch, H. J., & Schwaller, M. R. (2014).

Smaller penguin colonies may go unnoticed because the resolution of satellite imagery can’t always detect smaller guano stains. However, scientists estimate that they can identify penguin colonies with about 3,000 breeding pairs approximately 50% of the time. Most of the penguins living in the Antarctic live in larger colonies, so researchers estimate that they can detect 97% of the penguins there.

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