What are the odds of being pooped repeatedly by a swarm of bees? Another great piece of party trivia from PlanterTomato.com.
Last week I parked myself in our hammock for the first time this year with the intention of getting some deserved rest from gardening and other chores on the to-do list.
While I sat looking at a magazine, I felt small raindrops hitting me. This was strange because there wasn't a cloud in the sky. I went back to reading, but the rain persisted and soon I noticed little yellow droplets appearing on the open page of the magazine.I looked up and observed a huge tornado of bees circling in the air about 10-15 feet above above my head. There were thousands and thousands of bees racing about.
The bees were swarming -- the method by which these little critters create new colonies; the old queen leaves with half of the worker bees; they circle in the air for a period of time before settling down on a tree, bush or other convenient location where they will build a new nest. The bees in this story appear to have been from a wild colony located in a neighbors tree. They did their flight over my backyard before taking off for parts unknown.
It was an amazing but scary sight. (see below photo of a swarm in flight care of the city of Chesapeake, Virginia). And as I watched them it dawned on me that the yellow rain falling from above sky above was bee poop. They nailed me pretty good and left lots of little yellow drops on the barbecue grill, my car etc.
I'm no stranger to being in the wrong place at the wrong time, but this was really ridiculous. I'm sure as individuals we've all gotten hit by an individual bee without knowing it (probably a bird or two as well) but I have never heard anyone complain that they got rained upon by thousands of bees.
I checked the internet and could not find a similar incident reported... plenty of cases of bees swarming, lots of information about colony collapse, even reports of car dealerships complaining about having to wash off the little yellow dots caused by individual bees from nearby hives, but no reports by individuals suffering a Pearl Harbor style bombing.
What are the odds of this happening? My inner geek was so intrigued that I just had to estimate the odds of being pooped on by a swarm of honey bees. I'm sure if you are a hobbyist or professional bee keeper, your odds will be much higher; this calculation is the odds of the average Joe taking the hit.
How I did the Calculation:
Broadly speaking, I calculated the probability of a hive swarming in a given location of 100 square yards during a particular 10 minute interval. I then calculated the probability of a person being outside in a given location of 100 square yards during a 10 minute interval. The probability of the bees and a person being in the same spot, at the same time, is calculated by multiplying the two simple probabilities.
Here are some of the particulars and assumptions for those interested...
- Locations - I used a space of 100 square yards as the basic unit of measure for figuring out where people and swarms might collide. I choose 100 square yards because this is the approximate space that the swarm in my backyard occupied during their flight. Rather than divide the entire US land mass into 100 square yard blocks, I used only those areas where people tend to be in reasonably dense communities. This space includes cities, suburbs and rural areas where people live and excludes forests, mountains, desserts and stretches of really unpopulated land. I used a US Census density map to determine these areas. As it turns out, this is about 30% of the total landmass of the US. Breaking this areas into 100 square yard "Locations" results in 36.1 million places where bees and people might intersect. [By the way, I got this estimate by using Photoshop to determine the populated areas (white pixels) and non-populated areas (black pixels)].
- Bee Data - The number of beehives in the US, swarming rates, etc come from various websites which are listed in the attached spreadsheet.
- Time Intervals Used In the Calculation - I did all calculations based on a day-length of 5 hours . I did this because bees tend to swarm during the hours of 10 am to 3 pm. Swarms occur during 3 months of the year in spring and early summer, so a 90 day time frame was used. Finally, bees swarm in the air for only a brief time before settling down. Based on my observation this is about 10 minutes. So that apples are compared to apples, I estimated how many people would be out of doors during the same time period of 10 am to 5 pm each day. I could find no hard data on this, so I assumed 5% of all people have jobs that have them outside all day long (all time intervals), 20% would venture out of work or the home for two 10-minute intervals during the 5 hour period, and 50% would go out one time (I reasoned this was OK since many people venture out of the office to buy lunch or run errands etc.) While people go outside more during the weekend, they will probably be out less during the winter so I did not make any particular adjustments, assuming that weekends and winters would balance out.
There are 36 million potential 100 square foot locations where a man-swarm encounter might happen. But this can happen in any of 2,700 ten minute time intervals during the 3-month swarm season. So the total number of Location-Time Intervals under consideration is huge -- over 97 trillion (36 million x 2,700).
Bees will swarm in only 1.2 million of these location time-intervals because there are relatively few bee hives in the US (2.3 million) and they only swarm for 10 minutes. The probability of a swarm happening in any given location time-interval is just .0000012%.
Likewise, people are indoors most of the time, venturing outdoors for just an estimated 225 million of the potential 97 trillion location time intervals. The probability that a person will be outside in any given location time-interval is .0002%.
As you can imagine, the occasions when bees swarm and a non-bee keeper is in the same spot is very, very rare. I estimate it at .0000000000028%.
Converting this probability to odds, shows that the odds are 1 to 352 million that you will be pooped on by a swarm.
For perspective, here are the odds for a variety of other events, care of Funny2.com:
Audited by the IRS 1 to 175 (ouch!)
Dating a supermodel 1
to 88,000
Struck by lighting 1 to 576,000
Killed by lightning 1 to 2.3 million
Killed by mountain lion in CA 1 to 32 million
Meteor hitting your house 1 to 182 quadrillion (quadrillion = 1,000 trillion)
So this means that your more likely to be pooped on by bees than hit by a meteorite, but your more likely to be eaten by a mountain lion than being pooped on by bees. Amazing.
For those interested, the calculations are attached in an Excel spreadsheet:
I am sorry to undo what you have done here. I cant go outside in summer without this happening to me. I must be under a flightpath for bees up high somewhere as I can't see them or hear them.
I would say it is impossible for me to sunbath for more than 10 minutes without getting hit. The whole house is covered. (untill it rains)
Sorry but it seems that is incredibly innacurate maths. Or I am a statistical anomally of biblical proportion. ( I know you did a lot of work) The whole area I live in gets it. It's just local knowledge. We are all cover'd in bee poo every day. Did you take into account people who live under these flightpaths? We can't be the only place in the world.
My email is [email protected]
Email me If you want me to send you photos. I was searching for information on where the bees are coming from and going to. Nothing yet.
I was provoked into coming in from the sun to do this search because today I was hit more than is usual. I would say five times in under 10 minutes.I wasn't keeping time. (Three times on the neck and face)
I would love to hear what you have to say.
Sincerely,
Cameron.
Posted by: Cameron | 05/19/2011 at 06:21 AM
Hi Cameron:
If you look at your car in summer, you may see some little yellow spots on it. Thats bee poop. So youre right in the sense that the odds of being hit by a drop here or there is much higher, particularly if you live near a wild hive.
What I calculated was the odds of being pooped on by lots of bees all at once because you happen to be under them when they swarm. Thats not a drop or two, its like being rained on. Believe me, youll know the difference. A swarm of bees looks like a tornado. The odds of this happening to anyone are much, much higher because swarms occur only during a brief season and for just 10 minutes.
With any luck, youll have this happen to you one day :)
-PlanterTomato
Posted by: H. Mark Delman | 05/19/2011 at 09:08 PM
whats the odds of being pooped on by a single be randomly.. just happened lol
Posted by: ray | 05/03/2013 at 01:06 PM