I had no idea this was a technique! From a British Antarctic Survey report on these devices[1]:
Accuracy
In field trials at Bird Island, South Georgia, the mean
error (great-circle distance) in position estimation
of static devices was 85 km, with standard deviations
in latitudinal and longitudinal errors of 0.61° and
0.99°, respectively (BAS, unpublished data).
I think they have a microprocessor, a battery, some sensors and flash memory. To get the data out you have to find/catch the swift and remove the device. The device wakes every 5 mins and records briefly.
Unit conversion: 0.04oz is approximately 1.14g, which sounds pretty impressive. But it can't be much heavier because a common swift typically only weighs around 35-56g (that's 1¼–2oz) according to http://www.commonswift.org/swift_english.html
According to the Wikipedia article linked by mongol, these devices can be as light as 0.3g. It's a battery, a phototube, a clock, and a recording chip. Longitude can be reconstructed from the time of most/least light, whereas the length of day and night allow reconstruction of latitude. Battery life is between 6 months and 5 years.
So, basically fish, in a thinner medium? There must be perpetually airborne macroscopic lifeforms flying/floating through the upper layers of some gas giant somewhere..
My layman theory for why it hasn't happened yet is that evolutionary pressure is not high enough. I believe the main advantage of not having to breed on land would be safety from predators. I guess there is no shortage of "safe" places.
Oh come on, use your imagination. The feet evolve for carrying eggs. They re-develop live birth. The young learn to hang on from the first moment. They fly earlier. That's just the ideas from 20 seconds of thought.
You realise that Emperor Penguins pretty much do this already?
When the egg is hatched, it cannot touch the ground or it will instantly freeze and the chick will die. So the female lays the egg onto her feet, where she holds it until she transfers it over to her partner, who will hold it on his feet for the weeks it takes the female to walk back to the ocean and replenish her energy reserves. When the chick hatches, it will spend the first few days (weeks?) of its life on its parents' feet, still never touching the ground, before it is old enough to venture out itself.
Evolution comes up with some pretty weird solutions to hard problems. :-)
It blows my mind that these birds spend summer in Europe, then migrate to Africa where they stay most of the year -- without ever touching ground there.
Don't birds need to preen their feathers periodically? That seems like a tricky maneuver while flying.
Reading the supplementary data [0], some of their results rely on sampling for 1 second every 5 minutes. So a bird could make occasional short landings for a quick preen & stretch without it necessarily being detected.
Preening has a few purposes; cleaning is most obvious, and beside that are straightening out disarranged feathers and ensuring that secreted oils are evenly spread for waterproofing.
For the swift in cruising flight, none of these requirements is likely to apply; the slipstream itself will help a great deal to keep the feathers in aerodynamic conformation, and dirt, parasites, and bodies of water are rarely found at altitude. (Rain is a plausible concern, and I'd be curious to know how swifts cope. Given their small size and altitude of flight, I wouldn't be surprised to learn they rarely notice any but the heaviest of storms.)
Why would this be an April fool's? Birds are amazing! This one has a variable-geometry wing adapted for an enormous degree of flying efficiency, and can spend almost its entire life aloft, landing only to lay eggs and rear young. They're fast as anything, too - the fastest known bird in level flight is a swift - and fly at altitudes well over a mile, where the air is too thin and the ascent too time-consuming for a lot of birds ever to go.
In a lot of ways, the swift is the Concorde of birds - small, sleek, astonishingly fast, and accustomed to operating in regimes beyond anything accessible to most of its kin. Fortunately for the swift, though, it need not rely on the mercurial good graces of Airbus to stay aloft.
Its weird having HN submission where only a subset of HNers can make comments though. I am happy for them to have a paywall but question whether it should be kept on HN if there is no information for most people to comment on.
It is the equivalent of linking to a paid book on Amazon and having a discussion about the book's content.
Well, if 99% of the book was freely available for viewing on 9 other websites than Amazon, I bet that people would complain A LOT for being given a link to Amazon instead of one of the numerous readable sites.
I don't have cookies disabled but I do have adblock and I get the paywall, but if I open it in an incognito window it shows so I'm guessing its also triggered by ABP (or some other condition).
Depends on the species; the white-throated needletail has been clocked doing about 170km/h, which is the fastest yet seen of any bird in level flight. (Peregrines, commonly awarded the "fastest bird" laurel, of course outdo this by far - but only in a power dive, where they get 9.8m/s² for free.)
And a link to the paper: http://www.cell.com/current-biology/fulltext/S0960-9822(16)3...