Smart USA employed zoology, statistics, engineering, and some cheeky graphic design to put an obnoxious Twitter follower in the right about the effects of bird doo-doo on cars. Here's the dirt on how much damage bird poop can cause to cars, and which color cars are most subject to aerial bombardment.

Clayton Hove (@adtothebone) tweeted, like a little bird, that he saw a bird had c---pped on a Smart Car. Totaled it. However, smart USA took umbrage at the implication that its cars could not hold up to a barrage of bird t---s, and the company set its statisticians to figuring out exactly how much bird c--p it would take to destroy a smart car.

The smart car's tridion safety cell can withstand 9,000 pounds of pressure, and the company did some simple math to figure out the weight of bird c--p required to damage the tridion safety cell. Its calculations were estimated and may not be exact. But they're not totally full of c--p, either, according to the company.

Turns out it would take 4.5 million pigeon c--ps to destroy a smart car, so an individual pigeon t--d is not particularly dangerous.  However, beware the much larger and more destructive emu: It takes just 45,000 emu t--ds to destroy a smart car. Emu t--ds are roughly 100 times more destructive than pigeon t--ds, according to smart USA's calculations.

Moreover, drivers of red cars may have the most to fear from a bird poop onslaught. According to a recent report by the British online retailer Halfords, red cars are more likely than any other color cars to be pooped on by birds, followed by black cars. Green cars were the least likely to be pooped on (however, as NewsFixNow pointed out, green cars are the least frequently sold).

This research does have a serious side because the problem annoys drivers, causes damaged paintwork, and affects the value of vehicles, Halfords car-cleaning expert David Howells said. To protect your bodywork from damage, droppings should be carefully cleaned off as soon as possible.

Either way, drivers -- particularly of red cars -- may want to beware of emus, although they are flightless and thus may have a slightly more difficult time c--pping on your car. Halfords estimated car owners spend about $89.3 million dealing with damaged paint jobs every year. That's a c--pload of money.