Fall Migration Observation Methods
Four Ways to Watch for Migrating Monarchs


Count Monarchs Flying Overhead
Go outside, lie down on your back, and simply look up at the sky!
  • Dr. Calvert watches monarchs arriving at the sanctuaries in Mexico.

    Watch for monarchs moving with "directed flight," traveling in a southerly direction. Monarchs migrate alone but, on big migration days, you may see many at one time.
  • Count "monarchs per minute."
    You can quantify your observations by counting the number of monarchs you see per minute. With a stopwatch, keep track of the time you begin and end, and keep a tally of the number of monarchs you see. At the end of your observation period, add up the total number of monarchs and the number of minutes you were watching. Then calculate the number of monarchs observed per minute. Try to put aside 10-15 minutes each day, at the same time each day, if possible. When you report to Journey North, tell us how many monarchs/minute you are observing.
  • Here are some examples from other observers: Here's an example of stationary count made regularly by students at Russell Dougherty Elementary in Edmond, Oklahoma. For example, see this September 15, 1999 observation from Ontario.


Count Monarchs at a Nectar Source
Your own butterfly garden is a wonderful place to conduct a migration study. Monarchs must find nectar all along their migration route, and you can draw them into your own backyard. Plant a butterfly garden that's rich with species that bloom (and produce nectar) in the fall.

You may find monarchs nectaring in large numbers--in a field of alfalfa, clover, a native prairie, or in roadside wildflowers, for example. Count the number of monarchs in a small quadrant. Then estimate the number of such quadrants in the full field, and multiply for an estimate of totals.


An estimated 27,225 monarchs were nectaring in this field!



Count Monarchs at an Overnight Roost (Aggregation)

If you're lucky enough to find monarchs aggregating at an overnight roost, follow the observation tips suggested by Dr. Brower. Also see Dr. Calvert's notes for information about the characteristics of the roost sites monarchs tend to select:


Count Monarchs as You Travel Along the Road
You can count monarchs each day as you ride to school, on a daily walk, or even on horseback, as Ms. Hartinger of Aurora, SD describes. Most important: Conduct your study at the same time each day, for the same period of time, so you can compare daily changes.

Two annual scientific studies are underway again this fall that use the "road census" method. These projects are collecting fascinating and useful data. By comparing the yearly averages, the data are an indicator of the fall monarch population size. Road counts are made each day at the same time of day. Read about how these studies are done, and then design a protocol for your own study: