2024 Vanessa Migration Project - A Vanessa Butterfly Biogeography Study

What is the Vanessa Migration Project?

The 2024 Vanessa Migration Project is an opportunity for you to share your observations of Vanessa butterflies in order to find out how these butterflies migrate and distribute themselves across North America each year. With your help, we will be able to track the movements and seasonal changes in distribution of these butterflies. We will add your data to an interactive map that shows how the range of Red Admirals and Painted Ladies expands northward in the spring and retreats southward in the fall. We are also mapping the date, location and flight direction of migrations of these butterflies.

What will we be able to learn from these observations?

What we can find out will depend on how many people send in observations. The more people who submit data, the more precise the map will be, and the more inferences we can make from it. Even a relatively small number of observations will show general patterns of movement. More observations closer together in time and space can show us how the butterflies' movements and distribution depend on regional weather patterns, such as wind direction, temperature, precipitation, and movement of warm and cool air masses. Sightings in different places along a migration route have also helped us estimate how fast butterflies travel during a spring migration - typically 50 miles (80 km) per day.

What species should I observe?

We are tracking the migration and seasonal distribution of four Vanessa species. These are:

  • Red Admiral, Vanessa atalanta
  • Painted Lady, Vanessa cardui
  • American Lady, Vanessa virginiensis
  • West Coast Lady, Vanessa annabella

What types of observations should I make?

Basically, we need to know three things about the butterflies that you observe:

  1. What species of butterfly you observed,
  2. When you observed it, and
  3. Where you observed it.

More specifically, we are seeking three types of observations:

  1. First Sighting Date of any or all of the four species at your location. Be watching and note the first day you see one of these butterflies. This is the same type of observation that Journey North and similar programs use to track northward-migrating Monarchs in the spring.
  2. Directional Migration of any of the four species. If you see a few to many Red Admirals or Ladies flying toward the same general direction, they may be migrating through your area. Note the date, your location, how many you see, and if possible, the flight direction (for the map, an observation such as "north", or "east-northeast" should be sufficient). You can also report the azimuth from 0 through 360 degrees in the notes, where north = 0 degrees, east = 90 degrees, south = 180 degrees, and west = 270 degrees.
  3. Presence or absence of these butterflies at other times during the season. If you see them at other times during the season, please report your sightings. You can also note how many you saw over some interval of time during the day. If you already make repeated butterfly surveys during the season, we would appreciate your observations of how many Red Admirals or Ladies you see during each survey. Regular periodic survey data from as few as a dozen locations in various parts of North America could be enough to show interesting patterns of how the populations of these butterflies vary over time on a subcontinental scale.

Would local weather data also be useful?

Yes! Because butterflies depend on warmth from the air and sunshine to fly and stay active, local conditions as temperature, type and extent of cloud cover, wind speed, and wind direction greatly affect whether and when one sees butterflies that day. All of these factors also affect the abundance and flight direction of migrating butterflies. You can collect your own weather data, or use hourly data from the U.S. National Weather Service. For this project, an observation such as the following: "The wind was south-southwesterly at 10-15 miles/hour, under mostly sunny skies with scattered cumulus clouds and temperatures in the mid- to upper 60s F" is sufficient.