Counting Albatrosses from Space
Satellites can help scientists keep track of these endangered birds at the bottom of the world.
Nearly 400 miles above earth, there’s a hunk of metal taller than an elephant and heavier than a rhino. It’s a privately operated satellite named WorldView-3 that’s been orbiting the planet every 97 minutes since 2014, taking tens of thousands of high-resolution pictures as it rips across the edge of our atmosphere. In addition to its duties monitoring flood damage, tracking invasive plant species, watching crops for drought stress, and scouting landscapes for the oil, gas, and mining industries (nobody’s perfect), it can help conservationists keep an eye on some of the planet’s most far-flung critters.
The albatross is one such animal. With an up-to-11-foot wingspan that would dominate most people’s living rooms, these birds soar across the southern seas for months on end, touching down on terra firma only to breed and raise chicks. Many of the craggy islands albatrosses call home are remote and uninhabited—and even if you could maneuver a boat up to one without its getting smashed to smithereens, you’d have to climb cliffs hundreds of feet high to reach the grassy plateaus where albatrosses make their nests.
All of these factors make albatrosses difficult to study, which is troublesome considering that all six species in the Great Albatross genus appear on the International Union for Conservation of Nature’s Red List.
Even living at the ends of the earth isn’t enough for albatrosses to escape humanity’s negative influence. Albatross chicks sometimes choke to death on ocean plastic that their parents inadvertently feed them. And on some islands, invasive species like rats, left behind by ships, feed on albatross eggs and chicks. (Even house mice have been known to “scalp” albatross chicks.)
But according to the IUCN, the largest threat to these great white birds is related to the longline fishing industry. Albatrosses have learned that if they dive down fast enough, they can nab the bait fishermen toss into the sea before it sinks. Unfortunately, the morsels become the birds’ last suppers when they become stuck on the hooks holding the bait and get dragged down into the icy depths by the heavy line.
If we’re going to learn the best ways to conserve albatrosses, we need to track their population sizes—and frankly, the birds are hard to survey the old-fashioned way. Take the wandering albatross. We know, for example, how many breeding pairs of that species were on the Prince Edward Islands in the austral summer of 2001–02 because someone conducted a study at that time. Same with Marion Island and South Georgia for other summers. But these are just snapshots. How many albatrosses of all kinds are flying around, dropping eggs on various islands strewn across the Southern Hemisphere? That’s anybody’s guess.
“If there are sudden declines in albatross numbers, we need to know about them quickly so that we can act on them before it is too late, especially for birds that are so rare,” says Peter Fretwell, a geographer with the British Antarctic Survey. And it would sure help, he adds, if we could monitor these colonies on a yearly basis.
This is where the fancy satellites come in. For the past few years, scientists have been using satellite images to count animals, such as polar bears, wildebeests, and southern right whales. There are, however, some limits to the technology. Satellites, after all, can only spy on animals of a certain size, and all of those previously mentioned range from pretty big to positively ginormous.
Albatrosses may be large birds, but they are puny compared with a whale. Still, with more-powerful imaging platforms like the one offered by the WorldView-3, we can now zero in on smaller wildlife. Fretwell proved this in a new paper published in the journal Ibis earlier this month by showing that albatross counts from space produce population estimates comparable to those taken on the ground.
The benefits are many. For one, scientists can now count albatrosses and other animals without spending a ton of money and time getting to remote locations. Satellites also don’t have to worry about illness, injury, or a region’s political instability. And because they silently and stealthily gather their information from miles above, satellites have no direct impact on the species on which they eavesdrop.
Of course, it’s not all gravy. Michelle LaRue, a research ecologist at the University of Minnesota who currently uses satellites to count Weddell seals, says the images can be pretty expensive to purchase at higher resolutions, especially when you have a lot of ground to cover. Scientists are also limited to counting animals that stand out against their background and in areas without much vegetation. “So we won’t be able to use it on tigers in India or Thailand,” she says.
But conservation strategies are seldom one-size-fits-all, and LaRue says it is still a “pretty cool tool” for certain situations, to which we can now add nesting albatrosses. And who knows what other species might yet benefit from this developing technology?
In 2015, Congress relaxed restrictions on commercial satellites, nearly doubling the available resolution from a clarity of 50 centimeters to 30. This incremental advance is what allowed Fretwell and his coauthors to zoom in on individual albatrosses. The ability to enhance the images further in order to benefit even more endangered species exists, but doing so is prohibited by law because it raises all kinds of privacy issues—for people, not so much for birds or seals. Thankfully, scientists are still able to conduct some meaningful work at the resolutions they do have access to.
“If this is as good as it gets, I think that’s pretty darn good,” says LaRue. “We can see albatrosses. That’s awesome.”
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