How Many Butterflies?

Every winter, scientists visit Mexico’s 12 traditional sanctuaries and measure the area of forest covered by monarchs. In winter 2018/2019, the colonies covered an area of 6.05 hectares (as of December, 2018). They measure area because estimates of individual butterflies in a colony vary too widely to be reliable. Such estimates range from 10 to 50 million monarchs per hectare.

Try This! Monarch Math

Using data from this winter, you can see how imprecise estimates of individual butterflies are. Estimate the number of butterflies in 6.05 hectares of forest.

• If there are 10 million monarchs per hectare there would be ____________ million monarch butterflies wintering in Mexico.

• If there are 50 million monarchs per hectare there would be ____________ million monarch butterflies wintering in Mexico.

• Based on these estimates, there are between _________________ and _________________ monarch butterflies wintering in Mexico.