Can Birds Eat Rice? The Science of Throwing Rice at Weddings


Can Birds Eat Rice The Science of Rice at Weddings
Birds can eat rice. If you throw rice at a wedding and birds eat it, it won’t harm them.

You may have heard that you shouldn’t throw rice at weddings because birds eat it and it expands in their stomachs and harms them or even makes them explode. It’s not true. In fact, there are birds that eat so much rice that they are considered agricultural nuisances. A good example is the Java sparrow (Lonchura oryzivora), which is now an endangered species, in part from its extermination as a rice field pest.

Why People Throw Rice at Weddings

Throwing rice at weddings dates back to at least ancient Roman times and probably much earlier. Wheat, rice, and other seeds are symbols of prosperity. Throwing them onto the happy couple is a way of wishing them good fortune in their new lives together. While rice has always been the grain of choice in India and Malaysia, it replaced wheat in the Western world as wheat became more expensive and harder to find.

Why People Thought Rice Killed Birds

The “theory” (using the term very loosely) is that rice expands when it enters a moist environment, like a bird’s stomach. If birds eat enough of it, the pressure becomes too much for the animal’s stomach and it bursts and kills the creature. Likely, this comes from observations of rice expansion during the cooking process.

In the 1980s, two events expanded the myth. First, Rep. Mae S. Schmidle proposed a bill in Connecticut in 1985. Mrs. Schmidle stated that ”An Act Prohibiting The Use Of Uncooked Rice At Nuptial Affairs” would protect birds from injury and death. She said,

‘Unfortunately, when the birds eat the raw rice, they cannot digest it. When it gets in their stomachs, it expands and causes them to have violent deaths. I’ve heard from several ministers who say that the next morning after a wedding, they see all these birds toppled over because they got poisoned by the rice.’

It did not matter that the Connecticut Audubon Society and Connecticut Ornithological Society disagreed. The notion stuck. In 1988, newspaper columnist Ann Landers referenced the proposed bill in Connecticut and said rice “can indeed be lethal to wildlife.”

What Science Has to Say

There are multiple pieces of evidence that refute the urban legend.

First, there are the observations from rice farmers and ornithologists of birds eating rice and raising their chicks on it. If that’s not good enough, chemistry explains the differences between cooking rice and digesting it.

During the cooking process, heating rice in boiling water allows for rapid absorption of the water by the starch and expansion of the grains. The starch granules are amylopectin, which contains many water-loving hydroxyl groups. As rice cooks, water molecules attach to these hydroxyl groups and expand the space between molecules. The entire rice grain swells.

Digestion is different because the temperature is much lower, food particles get broken apart mechanically, and enzymes break down carbohydrate molecules. A bird’s body temperature is higher than a humans, but much lower than the boiling point of water. Rice does not “cook” and expand inside a bird’s body. Instead, birds break apart food in an organ called the crop. Saliva contains enzymes that immediately soften food and break the chemical bonds in carbohydrates. So, the amylopectin in starch granules breaks into amylose subunits.

In 2005, James Krupa and his students conducted an experiment testing the effect of rice on birds and proposing an activity so that others could replicate his results. He found that bird seed expands more than rice at room temperature. So, if rice is risky to birds because it swells inside a bird’s digestive tract, then birdseed is even more dangerous. Also, instant rice expands more at lower temperatures than regular uncooked rice. He offered both instant and regular uncooked rice to birds. Birds preferred the regular rice, but they were unharmed regardless of which type of rice they ate. The conclusion: birds can eat rice.

The Real Risk From Throwing Rice at Weddings

While throwing rice at a wedding won’t harm your feathered friends, there are two legitimate reasons why it’s not the best option for wishing the bride and groom good fortune.

The first reason is that cleaning it up is a pain. Someone has to sweep it up after the event. However, this issue also applies if you throw bird seed, flower petals, or even biodegradable confetti.

The second reason is that rice poses a safety hazard for the wedding party and wedding guests. If you get those hard grains under your heels or dress shoes, slipping and falling are strong possibilities.

Can Birds Eat Alka-Seltzer or Pop Rocks?

Another common urban myth is that seagulls and pigeons explode if you feed them the over-the-counter antacid medication Alka-Seltzer. The thinking is that bird saliva activates the tablets, releasing bubbles in the stomach. Pseudoscience says that birds can’t burp, so the gas swells the stomach until it explodes.

For the same reason, birds supposedly can’t eat Pop Rocks candy. These candies contain little pockets of carbon dioxide gas that expand with a popping sound as the sugar dissolves.

It’s simply untrue that birds can eat carbonated foods. Birds typically don’t pass gas, but that doesn’t mean they can’t. Also, birds regurgitate food at-will. What really happens is that a gull or other bird eats an Alka-Seltzer tablet and then throws it back up (plus a lot of foam). If you search the internet, you’ll find videos of pet budgies and parrots that think Pop Rocks are a highly entertaining treat.

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