A group of geographers and ecologists from three continents has taken an unprecedented look at Antarctica's emperor penguins. Using very high resolution (VHR) images from satellites 450 kilometers above Earth, the team has come up with the first total population count for an entire species. With a whopping 595,000 penguins, they found nearly twice as many emperor penguins as did previous studies, and they counted 46 colonies, up from the earlier total of 38. Their results were published today in PLoS One.

"We were very surprised by the results," says geographer Peter Fretwell of the British Antarctic Survey, one of the study's authors. In 2009 Fretwell's group, in collaboration with the University of Minnesota's Polar Geospatial Center (PGC), Scripps Institution of Oceanography and the Australian Antarctic Division, took satellite images of emperor penguins during their September-through-December breeding season. Using a sharpening technique, a method of image editing commonly used to improve map quality, they adjusted their images to differentiate between adult penguins, their droppings and shadows, details that had confounded earlier efforts to survey the species. Using ground-based counts for reference, they developed an algorithm to identify which pixels in an image represented penguins, as opposed to the surrounding environment, and counted the hundreds of thousands of birds.

Previous measures have relied on either ground tallies or aircraft surveys, which require scientists to observe and count a group of penguins, then estimate the total number. The latter method can be costly and the former fraught with challenges. An emperor penguin colony packs thousands of penguins together, and the animals congregate in areas that hover at –50 degrees Celsius. Many of the colony locations are inaccessible by land or sea.

"There's literally no other way to do this," says ecologist and research fellow Michelle LaRue of the PGC, also a co-author. "The sea ice is way too extensive, it would be way too dangerous. I think this is probably the only cost-effective and efficient way to do it."

Monitoring the animals inhabiting both polar regions has taken on new importance as humans try to determine the impact climate change is having on various species. A team of scientists from a number of U.S. and Russian institutions have launched an aircraft-based survey of Bering Sea ice seals to evaluate how diminishing sea ice affects them.

LaRue is working on similar satellite projects to study Antarctica's Weddell seals, and biologist Heather Lynch of Stony Brook University in New York State is using satellite imaging to study crested and brushtail penguins on the White Continent. Satellite studies are a particularly good match for dark colored species that live on the ice as the animal is easy to spot on a white backdrop. LaRue also observes that given the high resolution of satellite cameras, other kinds of surveys—such as of deserts or savannas—are possible. To illustrate the strength of the satellite imaging, she explained that despite being read from hundreds of kilometers above Earth, a single pixel within an image represents a 61- by 61-centimeter area, or an area as wide as a grown man's shoulders.

Whereas the emperor penguin's environment may be too harsh for a human, the flightless bird is well adapted to its home. The hostile landscape ensures minimal competition and predation, and the waters are rich with scrumptious sea life. The penguins are facing new perils, however. The sea ice on which they breed is among the most susceptible habitats to climate change.

Last year Fretwell and Trathan, with Bernard Stonehouse of the Scott Polar Research Institute in England, announced the disappearance of an emperor colony first spotted in 1948. Its distance from other colonies, gradual population decline and the region's record loss of sea ice suggest that the colony's collapse is related to rising temperatures. The case illustrates why regular satellite imaging of the world's penguin population is needed, so scientists can monitor these species made vulnerable by a warming planet.

12 Comments

1. 1. RemieV 08:14 PM 4/13/12

   Hahahahhaha... I have to know who wrote the headline. Penguins from Space?? Also makes it sound like they're our new evil overlords, what with the 'emperor' part. You have now fully brightened my day.

   Reply | Report Abuse | Link to this

2. 2. geojellyroll 01:37 PM 4/14/12

   "The case illustrates why regular satellite imaging of the world's penguin population is needed, so scientists can monitor these species made vulnerable by a warming planet.'
   
   Really?
   Environment Canada last week annnounced that polar bear populations are at their highest levels since first surveys 36 years ago. This didn't fit the agendas of the GW groupies at Scientific American.

   Reply | Report Abuse | Link to this

3. 3. alan6302 02:59 PM 4/14/12

   The human census is likely off by more than 10%

   Reply | Report Abuse | Link to this

4. 4. ronburley 03:56 PM 4/14/12

   Geojellyroll,
   
   What you neglected to mention in your cherry-picking of data about polar bears is that Environment Canada continues to list polar bears as a species of concern and that the increase in polar bear population is the result of conservation efforts rather than a contrary indicator of climate change. Moreover, EC specifically names climate change as a continuing threat to polar bears.
   
   If you are going to use data to make your point, you would be far more credible if you happened to read beyond the headlines.

   Reply | Report Abuse | Link to this

5. 5. And Then What? 09:52 AM 4/15/12

   This is outrageous! Couldn’t the Penguins make a case against us for inter-species Voyeurism based on our covert “peeping” in on them? How would we feel if someone placed hidden cameras in our bedrooms and bathrooms? I think there is an opportunity here for a budding lawyer to take up this case and make a name for themselves as advocates for “Penguin Rights”. I mean really this is going to far. Come to think of it what about the Penguin’s neighbors who may have been indiscriminately caught on camera? A real sharp lawyer could make a fortune in the seafood processing business by demanding that their fee be paid in shrimp and fresh fish to be delivered to an Antarctica based processing plant.

   Reply | Report Abuse | Link to this

6. 6. brock2118 09:21 PM 4/15/12

   I thought the penguins all got hot and were trying to bust into Al Gore's hyperairconditioned mansion.

   Reply | Report Abuse | Link to this

7. 7. jtdwyer 08:05 AM 4/16/12

   The article states:
   "Using ground-based counts for reference, they developed an algorithm to identify which pixels in an image represented penguins, as opposed to the surrounding environment, and counted the hundreds of thousands of birds."
   
   That's great as long as this statement indicates that they used alternative methods of counting and estimation to test and confirm the accuracy of their algorithm, as I hope it does.

   Reply | Report Abuse | Link to this

8. 8. Simontcp in reply to geojellyroll 11:16 AM 4/16/12

   The world's temperature has already gone downward this year, so many experts seemingly do not emphasis the global warming...

   Reply | Report Abuse | Link to this

9. 9. jgrosay 04:04 PM 4/16/12

   We all thought that Pu-Yi was the last emperor. Was he?

   Reply | Report Abuse | Link to this

10. 10. IslandGardener 03:23 AM 4/19/12

    I've just signed up to the Scientific American weekly review email and this is the first article I've looked at. I'm really impressed by the article.
    
    I'm really disappointed by the comments. A fascinating article about one of the most beautiful and impressive and fascinating species on the planet, and about research which may help us understand how climate change is affecting them, and almost all the comments are...
    the usual immature head-in-the sand stuff complicit with the massive fossil fuel industries?
    
    Are there any other readers out there who actually want the human species to act like responsible adults?!
    

    Reply | Report Abuse | Link to this

11. 11. akkmm in reply to jtdwyer 01:57 PM 4/20/12

    Your comment includes your answer. The first part of the quote is "Using ground-based counts for reference..."
    
    
    

    Reply | Report Abuse | Link to this

12. 12. poihths in reply to IslandGardener 08:08 PM 4/22/12

    Unfortunately, the level of commentary across Scientific American is dominated by people who have no respect for science, for intellectual inquiry, or for the difference between truth and falsehood. Not to mention that an astonishing number of them demonstrate a nearly complete inability to formulate a simple English sentence and to spell the words in it correctly. My advice is - skip the comments entirely. They serve no purpose and will waste your time.

    Reply | Report Abuse | Link to this