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Wikimedia Commons

Some Birds Benefit From Having Parasites

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Wikimedia Commons

Cuckoos are some of nature’s most practiced—and successful—con artists. Many species from this large family of birds are brood parasites. They lay their eggs in the nests of other birds and outsource the raising of their chicks to these foster parents, whose own babies are often murdered by the new arrivals. Even when the cuckoo doesn’t defenestrate its adoptive siblings, it usually outcompetes them for food and parental care. So they're typically lousy house guests—but scientists now think that hosting a murderous freeloader might have some benefits, too. 

Because of the costs of caring for them, many cuckoo hosts have developed defenses against them, like recognizing and evicting alien eggs or mobbing adult cuckoos when they try to sneak their eggs in. In northern Spain, carrion crows are plagued by great spotted cuckoos. More than two thirds of their nests are parasitized, but the crows don’t drive the cuckoos out. The cuckoo chicks leave their foster siblings alone as well, and they’re raised alongside each other without many problems. Even though they have to share food and attention from mom and dad, the crow chicks in parasitized nests don’t seem to be in any worse condition than ones that grow up cuckoo-free. 

Sometimes birds don’t defend their nests because cuckoos are a relatively new problem, but the crows and cuckoos have been neighbors for ages. Biologist Daniela Canestrari wondered if the crows instead keep the cuckoos around because they get something out of it. 

Canestrari has spent more than a decade studying crows in Europe, and long-term data from her years of crow studies showed that eggs in both parasitized and nonparasitized nests had roughly the same chance of hatching. Once the chicks were born, the parasitized nests were more successful (that is, more likely to produce at least one crow fledgling) than the ones without cuckoos.

To see if there was a benefit to getting saddled with another bird’s chicks, Canestrari and her team tracked four different kinds of crow nests: 14 ones that they’d transferred cuckoo hatchlings to; 16 ones they’d removed hatchlings from; and 28 parasitized and 24 non-parasitized ones that they left alone to serve as controls. The chick-shuffling experiment suggested a direct link between cuckoo chicks and the success of a nest. The nests that had their cuckoo chicks removed failed more than any of the others, including the controls, while the ones that had cuckoos added to them were the most successful of all the nests. 

So how do cuckoo chicks help crows when all they do is sit around and take free meals? Jostle a great spotted cuckoo and you’ll find out. When the chicks are harassed, they secrete a foul-smelling goo from their cloaca (a bird’s entrance and exit for mating and getting rid of waste) that’s loaded with “caustic and repulsive” ingredients like acids and sulfurous compounds. It’s not something you want around your mouth or nose, and the researchers thought that it might scare predators away from the nests. When they offered bits of meat covered with either cuckoo secretions or plain water to feral cats, falcons and other crows (the three main groups that prey on crow nests), the predators overwhelmingly rejected the one with the cuckoo goo.

Canestrari’s study area was home to plenty of predators, which cause the failure of anywhere from a quarter to three-quarters of the crows’ breeding attempts each year. As much of a pain as a cuckoo can be sometimes, any help a crow can get keeping all these predators at bay might be worth the hassle of taking care of someone else’s kids. The benefit only comes when the cuckoo actually has predators to repel, though. In years with overall low rates of predation and nest failure, cuckoo-parasitized nests were less successful than they were during times with more attacks from predators. 

The line between friend and foe, or parasite and protector, isn’t always as cleanly drawn as it seems. As the shifting relationships between crow and cuckoo show, a lot depends on context and sometimes even the most obnoxious nest mates are nice to have around. 

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iStock // Ekaterina Minaeva
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technology
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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© Nintendo
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fun
Nintendo Will Release an $80 Mini SNES in September
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© Nintendo

Retro gamers rejoice: Nintendo just announced that it will be launching a revamped version of its beloved Super Nintendo Classic console, which will allow kids and grown-ups alike to play classic 16-bit games in high-definition.

The new SNES Classic Edition, a miniature version of the original console, comes with an HDMI cable to make it compatible with modern televisions. It also comes pre-loaded with a roster of 21 games, including Super Mario Kart, The Legend of Zelda: A Link to the Past, Donkey Kong Country, and Star Fox 2, an unreleased sequel to the 1993 original.

“While many people from around the world consider the Super NES to be one of the greatest video game systems ever made, many of our younger fans never had a chance to play it,” Doug Bowser, Nintendo's senior vice president of sales and marketing, said in a statement. “With the Super NES Classic Edition, new fans will be introduced to some of the best Nintendo games of all time, while longtime fans can relive some of their favorite retro classics with family and friends.”

The SNES Classic Edition will go on sale on September 29 and retail for $79.99. Nintendo reportedly only plans to manufacture the console “until the end of calendar year 2017,” which means that the competition to get your hands on one will likely be stiff, as anyone who tried to purchase an NES Classic last year will well remember.

In November 2016, Nintendo released a miniature version of its original NES system, which sold out pretty much instantly. After selling 2.3 million units, Nintendo discontinued the NES Classic in April. In a statement to Polygon, the company has pledged to “produce significantly more units of Super NES Classic Edition than we did of NES Classic Edition.”

Nintendo has not yet released information about where gamers will be able to buy the new console, but you may want to start planning to get in line soon.

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