Directions for Monitoring
Site Location, Boundaries, and Measuring Milkweed Density
Finding a site with milkweed is the first step in the MLMP protocol and often the trickiest for many volunteers. Most species of milkweed grow extremely well in disturbed areas, so logical places to look include pastures, roadsides, bike paths, agricultural fields, vacant land or cultivated gardens. Natural and restored prairies, CRP land and nature centers and preserves frequently have patches of milkweed that have already been identified or can be readily located. If you are using land that is owned by someone else, either privately or publicly, let the owner know about the project and get permission to monitor the land. Wonderful partnerships have been formed and community interest sparked when monitoring at a site outside your own backyard. The number of milkweed plants at monitoring sites varies from just a few in a small garden to several hundred in a large field.
When you define the boundaries of your site, think about the large contiguous area in which the milkweed is growing, not the seemingly separate patches of milkweed that appear throughout the site. For example, if you are monitoring milkweed in your garden, the milkweed may be concentrated in a small area, but the whole garden is actually your measured site. If you are monitoring a meadow that has milkweed by the pond, another patch by the road and a third patch on the hillside, do not treat these as three separate sites but rather part of a large site that is biologically similar and measure it accordingly. There are exceptions to these general rules. If, for example, you are monitoring a large field in which there is only one dense patch of milkweed and no other plants throughout the site, you might decide that this patch alone is your site. Likewise, if the meadow described above has a patch of swamp milkweed near a pond and common milkweed scattered throughout the rest of the site, you may decide to consider the swamp milkweed by the pond as part of a separate site. A good general rule is: if you have a biological reason for calling two milkweed patches two separate sites, you should do so. Otherwise, don’t.
Calculating milkweed density is an important activity that is done only once, usually several weeks after the first appearance of milkweed to assure that you are seeing all of the milkweed at your site. If you can count all of the milkweed at your site, you will have a true picture of the number of plants per area measured. If you cannot count all of the milkweed, you will randomly sample square meter plots and count the number of milkweed in each. After sampling 100 different plots, enter the number of milkweed plants in each and the MLMP website will calculate milkweed density. Don’t worry about getting a lot of 0’s in your sampling plots. It would be an amazing site if every plot had at least one milkweed plant. Randomness in sampling is extremely important in this activity and the activities involving monarch densities, so be sure to read the protocol carefully or ask for help if you need it. Collecting accurate data is the cornerstone of excellent citizen science projects.
Remember, since the accuracy of the entire MLMP database depends on the accuracy of individual data sets, it’s key that your data reflect what’s happening at your monitoring site as accurately as possible. Thank you in advance for your carefulness and honesty as you work on this project. We’re all depending on you!
Since most of the MLMP sites have too many milkweed plants to check, all of the data we work with are actually estimates of the actual monarch densities at the sites. If you have a sit like this, there are a few things that will make these estimates as accurate as possible:
Choose the plants you check randomly! If you only look at plants that look “good,” there’s a good chance that you’ll overestimate monarch density. If you have questions about how best to do this, please contact us.
Look at as many plants as you have time for! The more plants you check, the better your estimate.
Check the plants carefully! If you miss tiny first instar larvae, or call a milkweed latex dollop an egg, your estimates will be off. Check the plants from the top to the bottom, including the stem and any seed pods or flower blossoms.
Be careful in your identification of the different larval instars! Check out our Monarch Life Cycle section for pictures and specifications of the different developmental stages.
- Datasheets and Field Notebook: You will need at least one copy of each datasheet, and possibly more depending on the number of weeks you monitor. A field notebook (journal type or spiral-bound) is also useful for recording other observations that don’t fit on the data sheets.
- Hand lens: A hand lens or magnifying glass is very useful for identifying eggs and small larvae.
- Meter stick or measuring tape (for measuring milkweed density): You will need a meter stick only once during the season, when you do yoru milkweed density.
- Rain gauge (for Activity #2, optional): If you can, mount an inexpensive rain gauge at your site. Try to find one that is designed to prevent the water from evaporating.
- Thermometer (optional): Mount an inexpensive outdoor thermometer at your site, or bring one when you visit the site to monitor each week.
- Field guides (optional): To identify monarch eggs and instars, use A Field Guide to Monarch Caterpillars or our Monarch Life Cycle section on this website. There is also a handy reminder on the back of our MLMP Clipboard. A guide to wildflowers is useful for identifying the blooming plants at your site.
- Containers for rearing larvae (for Activity #3): See Making a Rearing Cage for more information, as well as the Rearing Monarchs Responsibly fact sheet for instructions on how to rear them.
Enter Data Online - Login to our online data entry app and enter all your data online. You will have your own password-protected Main Menu page from which you will be able to fill in data from all of the monitoring activities. You will be able to modify them throughout the season and visualize your data as the season progresses. Please send us hard copies of your data at the end of the summer so that we can check our database for accuracy.
In addition, send hard copies of data - We use these to check for accuracy, but if you do not have access to a computer, please send us the hard copies of the datasheets you have completed. Retain copies of all the datasheets yourself, in case of a postal disaster!
Department of Fisheries, Wildlife & Conservation Biology
2003 Upper Buford Circle
135 Skok Hall
St Paul, MN 55108 USA
- Be confident. You have read the instructions, you have received training--you have the ability to make good decisions in the field.
- Be consistent. Once you make a decision, stick with it. Much of the utility of the monitoring data lies in comparisons within a site over time.
- Keep excellent notes. Document what you do. Fill out all fields on the data sheets, or explain why you can’t. If you need to deviate from the protocol, keep track of what you did and why.
- Ask for help when you need it. You can use email, the website, or snail mail to contact us or other monitoring project participants. We're more than happy to help our volunteers so don't be shy!
- Monitor regularly. Missing a week or two will not make your results useless or invalid--don’t let it be a reason to not participate in the project at all. However, if you need to miss a week or two due to illness or travel, you might try convincing a friend or neighbor to monitor for you. If you are short on time one week, you can just do Activity #1 and skip the other activities that week.