Every winter, scientists visit Mexico's 12 traditional sanctuaries and measure the area of forest covered by monarchs.

Scientists 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.

In winter 2018/2019, the colonies covered an area of 6.05 hectares (as of December, 2018). Using data from this winter, you can see how imprecise estimates of individual butterflies are.

A colony in El Rosario sanctuary.

• A monarch colony is a large cluster of butterflies.
• A monarch sanctuary refers to the whole forest within which the colony moves.

• 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.