A recent expedition to the Danger Islands, a chain of remote islands off the northern tip of the Antarctic Peninsula, used new technologies to discover and survey a breeding colony of over 1.5 million Adélie penguins (Pygoscelis adeliae). The discovery is reported in the journal Scientific Reports.
Borowicz et al found that the Danger Islands have 751,527 pairs of Adélie penguins (Pygoscelis adeliae) — more than the rest of the entire Antarctic Peninsula region combined. Image credit: Rachael Herman, Louisiana State University / Stony Brook University.
“Until recently, the Danger Islands weren’t known to be an important penguin habitat,” said Stony Brook University researcher Dr. Heather Lynch, a co-principal investigator for the project.
“These colonies have gone undetected for decades, partly because of the remoteness of the islands themselves, and partly the treacherous waters that surround them. Even in the austral summer, the nearby ocean is filled with thick sea ice, making it extremely difficult to access.”
Yet in 2014, Dr. Lynch and NASA scientist Mathew Schwaller discovered telltale guano stains in existing satellite imagery of the Danger Islands, hinting at a mysteriously large number of penguins.
To find out for sure, they arranged an expedition to the islands with the goal of counting the birds firsthand.
When the researchers arrived in December 2015, they found hundreds of thousands of birds nesting in the rocky soil, and immediately started to tally up their numbers by hand.
They also used a modified commercial quadcopter drone to take images of the entire island from above.
“The drone lets you fly in a grid over the island, taking pictures once per second. You can then stitch them together into a huge collage that shows the entire landmass in 2D and 3D,” said Northeastern University’s Professor Hanumant Singh, a co-principal investigator for the project.
“Once those massive images are available, our team can use neural network software to analyze them, pixel by pixel, searching for penguin nests autonomously.”
“The accuracy that the drone enabled was key. The number of penguins in the Danger Islands could provide insight not just on penguin population dynamics, but also on the effects of changing temperature and sea ice on the region’s ecology,” said Louisiana State University scientist Dr. Michael Polito.
“Not only do the Danger Islands hold the largest population of Adélie penguins on the Antarctic Peninsula, they also appear to have not suffered the population declines found along the western side of Antarctic Peninsula that are associated with recent climate change.”
The team found that the Danger Islands have 751,527 pairs of Adélie penguins, more than the rest of the entire Antarctic Peninsula region combined.
“Being able to get an accurate count of the birds in this supercolony offers a valuable benchmark for future change, as well,” said Dr. Stephanie Jenouvrier, a seabird ecologist at the Woods Hole Oceanographic Institution.
“The population of Adélies on the east side of the Antarctic Peninsula is different from what we see on the west side, for example.”
“We want to understand why. Is it linked to the extended sea ice condition over there? Food availability? That’s something we don’t know.”
“It will also lend valuable evidence for supporting proposed Marine Protected Areas (MPAs) near the Antarctic Peninsula,” added Instituto Antártico Argentino researcher Dr. Mercedes Santos, who is not affiliated with this study but is one of the authors of the MPA proposal.
“Given that MPA proposals are based in the best available science, this publication helps to highlight the importance of this area for protection.”
“The size of these colonies makes them regionally important and makes the case for including them in the proposed Weddell Sea MPA,” added Dr. Tom Hart, a researcher at Oxford University.
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Alex Borowicz et al. 2018. Multi-modal survey of Adélie penguin mega-colonies reveals the Danger Islands as a seabird hotspot. Scientific Reports 8, article number: 3926; doi: 10.1038/s41598-018-22313-w
