To a kid, a backyard is a place to play. But they might be surprised at how many critters they’re sharing their play space with.
Entomologists (otherwise known as bug scientists) conduct something called a bioblitz to get a general count of how many bugs live in an area. They turn over rocks, peer under logs, and pull bits off trees to check out the number of critters in a place. Children can try something similar using observation skills and—yes!—math; the activity also helps foster exploration.
“Spending time in nature and specifically looking for insects or other creatures as part of a bioblitz activity can expose children to the amazing diversity of life around us,” says entomologist Patrick Liesch of the University of Wisconsin-Madison. “It can also teach about the life cycles and ecological roles of these creatures.”
Luckily a bioblitz doesn’t mean your kid has to count every single critter in your backyard. (Unless, of course, you’ve got a really long video meeting coming up.)
"When biologists want to know how many animals live in an area, they can’t count every single bug, every animal,” says Sophie Gilbert, assistant professor of wildlife ecology and management at the University of Idaho. “We’ve come up with a way to take a small sample and extrapolate to get a good estimate of how many animals live in a given area.”
Here’s how to get kids crawling around your backyard.
First, gather supplies:
—notebook for observations; kids will use this to list bugs and note things like size, color, location, etc.
—4 sticks and string, a Hula-Hoop, or an empty box for marking off the area to be sampled; scientists call this a “quadrat”
—measuring tape to figure out the area of your sample
—smartphone to help take photos and identify creatures
Building the bioblitz
If kids are using sticks and string for the quadrat, place the sticks in the ground so that they form a square or rectangle. Loop the string around each stick until the square or rectangle is connected, and tie off tightly. (This way, the quadrat will always be the same size if it’s moved to another part of the yard.) If kids are using the Hula-Hoop or box, have them place it on the ground. (Get kid-friendly instructions for making a Hula-Hoop.)
Using the magnifying glass, count every insect inside the quadrat. Don't forget to look in between grass blades, on flowers, and under rocks. If kids are using a bigger stick-and-string quadrat, check out bushes and trees inside the space as well. “Different animals live in the grass than on the rosebush,” Gilbert says. Critters such as ants, beetles, and worms favor dark, damp areas like under rocks and fallen branches. On flowers and bushes, you might find aphids, ladybugs, and bumblebees.
Count the number of bugs inside the quadrat several times, and help kids take an average. Then move the quadrat to a different place in the yard and repeat. Do this in many sections of your yard. Make sure to write down all the data in the notebook.
Once kids have the average number of bugs per section of yard they sampled, help them average the sections together so you get one number: the average number of bugs in one quadrat. So perhaps a kid has sampled and averaged 10 sections of the yard. Add those averages and divide by 10 to get the average number of bugs in one quadrat. (Let’s say 40 bugs in this case.)
Now have kids use the measuring tape to figure out how many square feet are in the quadrat. For example, if the quadrat is 2 feet by 2 feet, your quadrat is 4 square feet. Divide the average number of bugs per quadrat (40) by the quadrat’s square footage (4). That means 10 bugs per square foot of yard.
Next, use the measuring tape again to help kids find the area of your yard. (Let’s say it’s 100 feet by 100 feet, so 1,000 square feet.)
Now just have children multiply the yard’s square footage by the number of bugs per square foot: 1,000 x 10 = 10,000 bugs in your yard!
If children don’t feel like doing all that math, that’s OK. Instead have them simply take notes on the creatures they find inside the quadrat. They can write down names, numbers, and details in their notebooks. Liesch also recommends watching a bug for a few minutes to observe how it behaves. Does it crawl around a lot? Does it wash itself? What path does it take?
Another bioblitz option is to be on the lookout for bigger animals with fur or feathers. The trick is finding an observation station where the animals won’t notice the humans. And instead of counting in a quadrat, they’ll count animals during a certain time. “Rather than sampling space,” Gilbert says, “you’re sampling time.”
Whether kids are looking for bugs, birds, or four-legged creatures, Liesch recommends sampling throughout the day since animals are active at different times. Birds are plentiful at daybreak. Fireflies, bats, and owls are active at dusk. Later at night is a good time for bug counting. That’s when Liesch checks for insects while he takes his dogs out just before bedtime. “It’s amazing how many different insects are attracted to outdoor lights,” he says.