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Does Wedding Rice Really Make Birds Explode?

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ThinkStock

Throwing rice at a newly married couple has been a tradition for thousands of years, possibly going back as far as the ancient Assyrians and Egyptians. The idea is to give the newlyweds good luck, fertility, and abundance using this symbol of a good crop. More recently, wedding meddlers have cautioned against throwing rice because it can kill birds who swoop down and eat it after the human revelers have left for the reception. The rice grains, absorbent as they are, supposedly start sucking up water in the birds’ moist innards and cause them to violently burst.

It's not clear where this idea came from, but it hit the peak of its popularity in the late 1980s when the Connecticut state legislature discussed a bill outlawing the tossing of rice at weddings and advice columnist Ann Landers printed a letter about the practice.

Wherever it came from, you can quit worrying about the birds.

The reality is that rice poses no harm to them. Wild birds eat uncooked rice all the time with no ill effects. Many types of waterfowl, shorebirds, and migratory birds depend on flooded rice fields to maintain fat in the winter. A bird called the bobolink eats enough rice that it's considered a pest by farmers and has earned the nickname "ricebird."

Besides the numerous birds that regularly eat rice and don’t explode, another thing to consider is the fact that dried rice grains are pretty slow to absorb liquid unless it's boiling, which birds’ stomachs certainly aren’t. Their internal temperatures generally range from 100.4 to 107.6 degrees F, well below the boiling point of any liquid that would be inside them. Even if birds did have boiling guts, any uncooked rice they consumed would be broken down well enough by their crops and gizzards that the pieces shouldn’t cause any problems as they expand.

Mythbusters or Gutbusters?

Now, these explanations of why rice is not bad for birds rely on two things: what we know about birds, and what we know about rice. We understand both pretty well, but wouldn’t a good experiment go a long way toward putting the myth to rest?

That’s what James Krupa’s students at the University of Kentucky thought. During the spring 2002 semester, Krupa and his 600 biology students decided to test the exploding bird myth with a series of experiments. They looked at the expansion of different types of grains, considered the strength of birds’ digestive organs, and tested an all-rice diet out on the professor’s pet birds.

The first notable thing they found was that white rice increased in volume by 33% when soaked, while bird seed expanded by 40%. If rice was going to make birds explode, then we’d already doomed them anyway with birdfeeders full of seed. The most significant expansion was seen in white and brown instant rice, which expanded 2.4 to 2.7 times its original volume when soaked. Of course, instant rice is usually more expensive than the regular stuff and comes in smaller quantities, so it's not very likely that anyone is throwing around opened packages of Uncle Ben’s at weddings.

But what if they did? To see if instant rice could burst a bird from the inside out, Krupa and his students built model bird crops from very thin plastic and from wet paper bags, and filled them with various grains and water. None of the plastic crops exploded, but a paper bag filled with instant white rice expanded and ruptured in about 15 minutes.

Not satisfied with their bird-gut surrogates, the students begged Krupa to test the rice out on real birds. Krupa felt confident enough that no birds would be harmed based on their previous results, so he agreed to turn the flocks of doves and pigeons he kept at home into guinea pigs. He fed 60 of his birds a diet of nothing but instant rice and water for a day, and monitored them for signs of distress or discomfort. Krupa reported that no birds choked, exploded, or otherwise were injured or died. None of them threw up or even showed any sign that they were in pain; they went through their all-rice day with no problems.

Birds, it seems, have no problem with rice, but this doesn’t mean that it's perfectly safe to throw at weddings. Hard, tubular grains spread out on the sidewalk in front of a church can still create a slipping hazard for another animal: wedding guests. The fear of slip and fall injuries and the lawsuits that go with them have led some wedding venues to ban rice—not for the birds, but to keep themselves out of court.

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Crafty Crows Can Build Tools From Memory
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Scientists have discovered yet another reason to never get on a crow's bad side. According to new research reported by Gizmodo, members of at least one crow species can build tools from memory, rather than just copying the behavior of other crows—adding to the long list of impressive skills that set these corvids apart.

For the new study, published in the journal Scientific Reports, an international team of scientists looked at New Caledonian crows, a species known for its tool usage. New Caledonian crows use sticks to pick grubs out of logs, sometimes stashing these twigs away for later. Tools are so important to their lifestyle that their beaks even evolved to hold them. But how exactly the crows know to use tools—that is, whether the behavior is just an imitation or knowledge passed down through generations—has remained unclear until now.

The researchers set up the experiment by teaching eight crows to drop pieces of paper into a box in exchange for food. The birds eventually learned that they would only be rewarded if they dispensed either large sheets of paper measuring 40-millimeters-by-60 millimeters or smaller sheets that were 15-millimeters-by-25 millimeters. After the crows had adapted and started using sheets of either size, all the paper was taken away from them and replaced with one sheet that was too big for the box.

The crows knew exactly what to do: They ripped up the sheet until it matched one of the two sizes they had used to earn their food before and inserted it into the dispenser. They were able to do this with out looking at the sheets they had used previously, which suggests they had access to a visual memory of the tools. This supports the "mental template matching" theory—a belief among some crow experts that New Caledonian crows can form a mental image of a tool just by watching another crow use it and later recreate the tool on their own, thus passing along the template to other birds including their own offspring.

This is the first time mental template matching has been observed in birds, but anyone familiar with crow intelligence shouldn't be surprised: They've also been known to read traffic lights, recognize faces, nurse grudges, and hold funerals for their dead.

[h/t Gizmodo]

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These Sparrows Have Been Singing the Same Songs for 1500 Years
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Swamp sparrows are creatures of habit—so much so that they’ve been chirping out the same few tunes for more than 1500 years, Science magazine reports.

These findings, published in the journal Nature Communications, resulted from an analysis of the songs of 615 adult male swamp sparrows found in six different areas of the northeastern U.S. Researchers learned that young swamp sparrows pick up these songs from the adults around them and are able to mimic the notes with astounding accuracy.

Here’s what one of their songs sounds like:

“We were able to show that swamp sparrows very rarely make mistakes when they learn their songs, and they don't just learn songs at random; they pick up commoner songs rather than rarer songs,” Robert Lachlan, a biologist at London’s Queen Mary University and the study’s lead author, tells National Geographic.

Put differently, the birds don’t mimic every song their elders crank out. Instead, they memorize the ones they hear most often, and scientists say this form of “conformist bias” was previously thought to be a uniquely human behavior.

Using acoustic analysis software, researchers broke down each individual note of the sparrows’ songs—160 different syllables in total—and discovered that only 2 percent of sparrows deviated from the norm. They then used a statistical method to determine how the songs would have evolved over time. With recordings from 2009 and the 1970s, they were able to estimate that the oldest swamp sparrow songs date back 1537 years on average.

The swamp sparrow’s dedication to accuracy sets the species apart from other songbirds, according to researchers. “Among songbirds, it is clear that some species of birds learn precisely, such as swamp sparrows, while others rarely learn all parts of a demonstrator’s song precisely,” they write.

According to the Audubon Guide to North American Birds, swamp sparrows are similar to other sparrows, like the Lincoln’s sparrow, song sparrow, and chipping sparrow. They’re frequently found in marshes throughout the Northeast and Midwest, as well as much of Canada. They’re known for their piercing call notes and may respond to birders who make loud squeaking sounds in their habitat.

[h/t Science magazine]

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