Due to the harsh antarctic climate, coming up with an accurate number of Emperor Penguins has proved to be extremely difficult. However, a new study using satellite imagery has done what may be the most accurate count of the large flightless birds yet done, pegging their population at around 595,000 birds — nearly twice the previous estimate.
To carry out their survey, the international team of researchers used satellite imagery of the antarctic in 2009 to find colonies of the birds. During the mating season, Emperor Penguins group together in large colonies to mate. The rest, we know from The March of the Penguins: After the female lays a single egg, the unhatched offspring is transferred to the male, who incubates the egg while the females leave en masse to feed. The females return around hatching time, and the fluffy chicks are raised by the mated pair.
These gatherings of mated pairs were critical to the study, as it meant that most of the birds would be concentrated in groups. In their study, the researchers found 46 colonies of birds around the coast of Antarctica. Three of these were only hypothesized to exist, and four of them were completely unknown to science.
Once the colonies were plotted, the team then turned to Very High Resolution imagery in order to better discern individual birds. Though their black backs stand out in stark contrast to the white landscape, shadows and piles of penguin poo would have thrown off the count in lower resolution imagery. Using their count of birds combined with information from spotters on the ground and some algorithmic chugging, the researchers believe there were about 238,000 mated pairs or 595,000 individual birds at the time the imagery was taken in 2009.
The team’s research was published this week in the journal PLoS ONE. The researchers write that this was the first ever complete census of a species using satellite imagery.
This figure is surprisingly high, especially in contrast with the last count of about 135,000–175,000 mated pairs. This doesn’t suggest a sudden surge in population, but rather highlights the limitations of the earlier penguin census. The authors of this latest study believe that their count is accurate, being based off over 80% of the penguin population. The accuracy may be improved, however, as more information from researchers on the ground comes in.
While a fascinating and worthy enterprise in its own right (I mean come on — penguins!), the researchers believe that understanding the size and distribution of the penguin population will be vital in the coming years. PhysOrg quotes biologist Dr Phil Trathan, an author of the study, as saying:
“Whilst current research leads us to expect important declines in the number of emperor penguins over the next century, the effects of warming around Antarctica are regional and uneven. In the future we anticipate that the more southerly colonies should remain, making these important sites for further research and protection.”
Since the research relied largely on satellite photos and can be reviewed in the warm comfort of a lab, the researchers hope to carry out the census periodically to better track changes to the population over time. Hopefully, their efforts will help scientists better understand the lives of theses strange, majestic birds, and help ensure their survival in these times of climatic uncertainty.
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