Spotlight: Nan Burke Creates Much-Needed Pollinator Habitat




For the past two years, beginning in late 2015, Nan Burke of Westborough has played an important role in SVT’s efforts to improve pollinator habitats in our region. She has been raising milkweed seedlings that we have planted on our properties and shared with our members to plant in their own gardens. The milkweed is essential habitat for the monarch butterfly caterpillar, and its nectar is also vital to other insects.

In Summer 2017, we offered 200 of these free plants to our members via e-mail, and they were all claimed within five hours! Clearly, Nan is one volunteer who is making a big impact in our region.

And now she has added a new project: Raising and releasing the monarch butterflies themselves.

In Fall 2017, we asked Nan to discuss both projects, and she provided some useful resources for others who are interested in raising monarchs.

What inspired you to start raising milkweed?

In Fall 2015, I helped Jesse Koyen, an SVT Mass-LIFT AmeriCorps member, harvest milkweed pods at the Cedar Hill Reservation in Westborough for a pollinator project. That December, Jesse asked me if I would start some seed over the winter. The idea was to have plants ready to plant by volunteers early in the summer so they could possibly bloom that year.

I said I could make a several-year commitment to this, and bought lighting with six high-output T5 fluorescent bulbs, and a 2x4-foot table setup sufficient for four flats of plants (about 200).

He told me to start them at the end of January, which turned out to be too early, since the plants were ready to be moved outdoors in March, but it was too cold to plant them. SVT put some of them in windows until it was warm enough to plant. I then started more seed and ended up delivering about 50 more plants to SVT that spring.

When the project was started in 2015, the milkweed population was low enough that this head start was necessary to get the plants out to the reservations. Next year will probably be my last growing seedlings, since the plants are getting a foothold in the reservations and volunteers’ gardens.

Why do you think this project is important?

Milkweed, a plant required for the monarch caterpillars’ diet, used to be common along the edges of farmers’ fields, road sides, and undeveloped land. In recent years, the practice of spraying glyphosate  to get rid of the weeds has caused this plant to dwindle in population, and with it, the monarch butterfly.

Milkweed is a hardy perennial with fragrant blossoms, and also supplies many pollinators with nectar to live on. Thus, encouraging the growth of milkweed not only helps bring back the monarch, but also supports the huge variety of pollinators essential to growing plants and crops.

Raising milkweed is really about more than monarchs. Herbicides aren’t the only threat: the neonicotinoid pesticides that threaten the honeybee endanger all pollinators. Having pesticide-free plants for pollinators is essential to their survival.

What is involved in raising milkweed plants?

Started indoors, it takes at least two months to raise a plant from seed to ready it for planting in a field. The lights need to be on timers, and run 14 to 16 hours per day.

The seedlings have three potting stages: the starter (covered flats on heat mats set to 70 degrees), the deep rooted flats with 50 cells each, and then individual pots.

Plants under lights need to be watered twice a day, and it takes a lot of time to move them to new pots as they grow. They do not take care of themselves!

How much time do you spend on the milkweed project each year?

I logged about 80 hours in the first year, including picking pods. I ended up raising two crops, and had a learning curve, so I spent a lot of time.

This past spring, it was closer to 40 hours. I did process and vernalize the pods, which took some time. (“Vernalize” means I stored them in simulated winter temperatures for six weeks.)

I will be experimenting in the future with “seed bombs,” or putting seeds in a clay mix that can be put on or in the ground in the fall or winter for germination in the spring. The clay protects the seeds from the birds. I had put out a lot of spare seed scratched into the ground of my yard, and later watched the turkeys eat most of it up!

What inspired you to start "raising" monarch butterflies?

Before this summer, I had not seen any monarchs at all for a couple of years, even though I have common milkweed and buddleia (butterfly bush) growing in my yard.

In mid-June, I saw my cat watching something outside my window. It was a monarch laying eggs on the milkweed. I located some eggs and started looking for caterpillars after several days (they hatch in three days). I was watching six through their instar molts, and growth to full size, and one day, they ALL disappeared. I looked for chrysalides and did not find any, so I feared that they’d died or been picked off by a predator.

Two weeks later, I saw monarchs again, some laying eggs. Since it takes 10 to14 days before monarchs eclose from their chrysalides, I thought maybe they were adults of the caterpillars I had monitored in June. I’d read about all the predators and diseases that beset monarchs, so I decided to collect some eggs and try my luck with growing them inside and releasing them as adults. 

I ordered some butterfly cubes (15” cubical mesh popup cages) online. I started with five eggs, then another came in on milkweed leaves I picked to feed the crew. All but one of these caterpillars made it to chrysalis.

Dawn Dentzer (who contributes photos to SVT's Nature Sightings) was going on vacation and had three chrysalides close to eclosure, and SVT asked me to watch these, too.  So I had eight chrysalides to watch. Two didn’t make it, but I ended up releasing six monarchs.

What is involved with raising butterflies?

Monarchs take about a month to go from newly laid egg to adult. The eggs take about three days to hatch and the caterpillars go through five molts (or instars) as they grow by eating milkweed, their only food.

When fully grown, they form a chrysalis, in which they spend 10 days or so transforming into an adult butterfly. While the caterpillars are growing, I need to clean up their poop and make sure they have a supply of fresh milkweed to eat in their enclosures .

The fourth and fifth instar caterpillars’ enclosure need to be cleaned up a couple of times per day. It only takes a few minutes. The pupating caterpillars don’t need anything done with them, unless they formed their chrysalis in an inconvenient place, like on a zipper or a food plant.

There are four generations of monarchs during a year, and the fourth migrates south, starting in late August. Ours [monarchs from New England] will winter over in southern Florida, but ones in the central part of the country will go to Mexico, and out west they go down the coast to Baja. See this chart on generations.

Next year, I plan to “tag” my monarchs to help a group called Monarch Watch better understand migration patterns.

How do you "capture" the crysalis?

After I lost track of the June caterpillars, I decided to raise some from eggs when I found them again in July. Next year, I may make some structures in my milkweed patch from tomato cages topped with panty hose to encourage wild caterpillars to pupate in a relatively safe location in June. For July, I’d like to locate eggs and raise them all the way to adult again, since it is easy to tag an emergent adult.

It is best to start from eggs because of the parasites and diseases that can hit caterpillars. For example, the Tachnid fly lays eggs in caterpillars, and you don’t know it until the larva erupt from large caterpillars or chrysalides and kill them.

My cage cubes can support up to 15 caterpillars each. I don’t plan to raise a huge number of them, but I think helping some along will make some difference.

Do you have to monitor them every day? (Can you go on vacation?)

Monarchs are pretty predictable. You do need to find somebody to clean up for them and feed them each day, as well as be able to release them when they eclose.   Some people end up putting the chrysalides in a semi-protected area outside if they have no other choice.

Have you inspired anyone else to raise milkweed or butterflies? Does anyone help you with your projects?

Some people are regularly sharing my Facebook posts on the projects and progress in them. I have been showing photographs in my art and craft communities.

What is your greatest satisfaction from the project?

Getting the picture of a fifth instar caterpillar munching on some milkweed I started last year from SVT was a big one. Seeing monarchs again in my garden after their absence and being able to raise and release them was also a big thrill.

It never ceases to amaze me about the transformations these insects undergo in their journey to adulthood, as well as the multi-generational journeys they make each year.

Third, it was exciting to know how much interest there was in the seed packets and plants on the part of members who took them home.

What do you like least about doing this?

Potting plants is very tedious and messy! Getting seeds distributed and planted outside in the fall is really the way to proceed now that there are some milkweed plants around. I am getting more interested in starting plants that attractive to pollinators so that my garden will be more attractive to them from spring to fall. If I start them from seed, at least I know they will not have been sprayed with harmful chemicals!

What advice do you offer for others who want to get involved with a conservation project such as this?

There is a huge amount of information and support available on the web for efforts like these. There are Facebook groups on raising monarchs and other butterflies that can answer questions about them. There are ebooks and other documents posted online.

Locally, getting to know other people who do these things in various organizations is also useful. I was amazed to find how many people who I already know had raised butterflies in the past. The SVT pollinator workshop last year was also really informational about the challenges all pollinators are having with loss of habitat, herbicides, and pesticides.

Anything else you'd like to add?

These key resources can help others get started, and they link to even more useful data:

Monarch Watch:

Journey North, Tracking Migrations:

Monarch Butterfly Shop:

Xerxes Society, for Invertebrate Conservation: