Hands-on Activity – Estimating Populations of Endangered Species

Can you use or re-work this point-counting activity to match the theme of your upcoming café? This Café was about rescuing an extremely rare species of butterfly found only in Ft. Bragg, NC, but the activity could be used to have teens get up and act as ecologists studying populations of any species.   Read the full Cool Café report this activity came from here

Rescuing Rare Butterflies Group Activity Background and Instructions


Students will simulate a field test performed by ecologists studying populations of various endangered species. This activity will allow students to recreate the process of point-counting and illustrate the difficulty of determining the accurate population sizes of four different species of butterflies.

Prerequisite information

Point-counting is a method that is used to predict the size of a population based on the number of butterflies one can see from a specific point. Ecologists compile all of these points to form a cohesive

Grid to help estimate the population of butterflies (or other species)

image of population density in specific habitats.


Each pair of students will attempt to observe a portion of the butterflies located around the room from the point at which they are sitting. They will then calculate the predicted population size of each species using the point-counting method.

Using multiple sheets of paper in two different colors, cut out two sets of butterflies. Each same-colored set should include two different sizes of butterfly (suggested: one in a color that blends in with the space and one in a brighter color that stands out). These represent four unique species of butterfly. Tape the butterflies around the room so that not all butterflies are visible from one location.

Activity Instructions

  1. Participants must stay in one location without moving or standing.
  2. Using the time provided, participants will partner up to count each of the four different populations of butterflies.
  3. Each participant will first individually count the number of individuals for each species and will record their geographic location on the radial grid provided.
  4. Groups will then compare the butterflies recorded on the grid to the butterflies recorded on their partner’s grid. A butterfly recorded in the same geographical space represents a confirmed sighting that both partners saw.
  5. Participants will work together to calculate the population sizes for each species of butterfly using the formula provided below.
  6. After the participants finish estimating the population size, compare the findings to the actual totals. How accurate were your calculations?