Lost and Found

Satellite images reveal unexpected colonies of a beloved animal

Earth has up to 10 percent more emperor penguins than we realized.

Antarctica's iconic flightless bird, the emperor penguin, has been keeping a secret from scientists.

New satellite data reveals that the population is actually slightly bigger than previously estimated. Their existence is boon to scientists aiming to get an accurate sense of how the climate crisis is affecting penguins.

There are between 5 and 10 percent more penguins on the planet than researchers previously reported, according to a new study. Researchers used satellite data to identify several new penguin colonies and breeding sites — locales key to penguin survival — in Antarctica.

As of 2019, researchers had identified 54 colonies of emperor penguins. The new report introduced eight new colonies to the polar family.

Close-up satellite image of the Dawson Lambton penguin colony.DigitalGlobe

The researchers also confirmed the existence of three breeding sites, which were first reported before modern satellite imagery was available, increasing total breeding locations to 61. That's a 20 percent increase, however, because the breeding sites are small, the total population increase maxes out at around 10 percent.

The findings were published Tuesday in the journal Remote Sensing in Ecology and Conservation.

Solid sea ice is vital — Every spring, emperor penguins famously march to their favorite breeding sites and lay eggs from May to June. After a 65-day incubation, the eggs hatch, then chicks spend a few months at home — they're not ready to be independent until the following December or January.

For all of that to happen, sea ice needs to remain stable for most of the year. But in Antarctica, penguins' frozen refuge is slipping away.

Emperor penguin with chicks.Richard Burt

A 2019 study found that assuming today's greenhouse gas emissions keep pace, 80 percent of emperor penguin colonies could become "quasi-extinct" by the year 2100. Under the Paris Agreement, researchers found, the damage could shrink to the point of losing just 20 percent of penguins. This means that our best-case scenario still means smaller penguin populations.

Meanwhile, other research indicates that Antarctia's ice is melting away. NASA data in 2018 found that ice melt is not just persisting, but accelerating.

That puts the new findings into perspective.

"We need to watch these sites carefully as climate change will affect this region," study co-author Phil Trathan, a researcher at British Antarctic Survey, said.

View from above — High-resolution satellite images are helping researchers keep track of how emperor penguins are doing. This latest discovery uses the satellite Sentinel2, which researchers say is more efficient than previous methods of data collection.

The small colonies detected by Sentinel2 prompt new ideas about reproduction and metabolic rate as it relates to penguins huddling. The new data also gives scientists the first evidence of emperor penguin colonies in offshore habitats.

Emperor penguins on sea ice near Halley Research Station on Antarctica's Brunt Ice Shelf.Christopher Walton

Tragically, the new findings could also mean that populations of these emperors have further to fall. Where they live are the same regions expected to suffer from ice melt.

"Comparison with recent modeling results show that the geographic locations of all the newly found colonies are in areas likely to be highly vulnerable under business-as-usual greenhouse gas emissions scenarios," the study authors write, "suggesting that population decreases for the species will be greater than previously thought."

Abstract: The distribution of emperor penguins is circumpolar, with 54 colony locations currently reported of which 50 are currently extant as of 2019. Here we report on eight newly discovered colonies and confirm the rediscovery of three breeding sites, only previously reported in the era before Very High Resolution satellite imagery was available, making a total of 61 breeding locations. This represents an increase of ~20% in the number of breeding sites, but, as most of the colonies appear to be small, they may only increase the total population by around 5–10%. The discoveries have been facilitated by the use of Sentinel2 satellite imagery, which has a higher resolution and more efficient search mechanism than the Landsat data previously used to search for colonies. The small size of these new colonies indicates that considerations of reproductive output in relation to metabolic rate during huddling is likely to be of interest. Some of the colonies exist in offshore habitats, something not previously reported for emperor penguins. Comparison with recent modelling results show that the geographic locations of all the newly found colonies are in areas likely to be highly vulnerable under business-as-usual greenhouse gas emissions scenarios, suggesting that population decreases for the species will be greater than previously thought.
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