A Week of Monarchs and Milkweed: Day 1

Monarch in flight

After finding monarchs at “Monarch Meadow” the previous week (see Hidden Meadow Reveals a Thrilling Secret), I could hardly wait to get back to the area to search for more purple milkweed (Asclepias cordifolia) and more monarchs. Molly Juillerat had gone to Monarch Meadow the following day, and on Monday, June 26, she had Crystal Shepherd, her seasonal botanist, go out to the meadow area just north of Monarch Meadow. I had planned to go there myself, so I jumped at the chance to go with Crystal. After I had suggested that as a likely next spot to investigate, Joe Doerr, Willamette National Forest wildlife biologist, had gone up there and found both milkweed and monarchs, as well as monarch eggs. So our job was to do a more careful survey of the area.

Female monarch nectaring on milkweed

We decided to access the area via an old road off of Road 2135, just past Big Pine Opening. A short bushwhack off the old road took us up to the south and lower end of the meadow complex (although we found an easier route back through more open woods on the way back). It only took a few minutes for us to spot the first monarch and the first caterpillar. Almost a week from when Sabine and I saw eggs at Monarch Meadow, it was about the right time for the eggs to start hatching. We set about counting eggs, caterpillars, and adults in each opening. Crystal kept a count and recorded information about habitat while I took photos and put together a preliminary plant list. At this point in the year and less than 3000′ of elevation, most things were dried out, and even the milkweed was mostly beginning to go to seed, so I’m sure there will be many more plants to add to the list that we didn’t spot that day. What we did see looked pretty much the same as what was growing in Monarch Meadow, with the exception of a population of field pussytoes (Antennaria howellii), a species I’ve seen much higher up near Balm Mountain (see Another Exciting Day in the Calapooyas: The Sequel) and in one higher elevation spot in Douglas County.

Female monarch ovipositing (laying an egg) on the milkweed

The biggest populations of milkweed were at the southern and northern ends of the complex. Incense cedars (Calocedrus decurrens) and small ponderosa pines (Pinus ponderosa) were invading the open areas, especially in the center of the area. This seemed to be inhibiting the milkweed in the central part of the complex. We did, however, find a few milkweeds and eggs and caterpillars in all openings. We supposed that the area was more continuously open once, and that removal of some of the small trees would help the milkweed and therefore the monarchs. We also noticed some small Oregon white oaks (Quercus garryana) getting shaded out by the conifers, so opening this area up would help valuable oak habitat as well. Restoring oak habitat is the focus of the nearby Jim’s Creek restoration project after evidence was found in the conifer forests of very old oaks that had been shaded out after fire suppression had allowed the conifers to outcompete them.

A monarch egg changing color probably as the caterpillar within is about to hatch

At the southern end we saw a female monarch flitting from plant to plant, and I was very excited to see a mating pair, the male flying around with the female hanging below her. That’s the first hard evidence I have of of a male butterfly. They disappeared fairly quickly around the back of some conifers, so I was unable to photograph them (I guess giving them a little privacy was the right thing to do anyway!). When we reached the northern end, we didn’t see any adult monarchs at first. There were also quite a few plants that had no eggs or caterpillars. I called out to any monarchs in the area that there were plenty of available milkweed plants—and lo and behold, a monarch flew in and started laying eggs!

1st instar caterpillar. Monarchs have 5 instars, or stages of growth (click here for a good description). As the caterpillar grows, it becomes too big for its skin and must shed it in order to continue to grow. In some caterpillars, they look very different from instar to the next. Monarch caterpillars do not look that different from one instar to the next except their coloration becomes stronger and their feelers get longer. 

2nd instar caterpillar on an inflorescence

3rd instar caterpillar

We ran out of time to check one last opening in the area, but we left satisfied that there was plenty of milkweed and the monarchs had found it all. Crystal’s count came to 23 eggs, 22 tiny 1st instar caterpillars, 13 older ones, and 4 adults. We didn’t count the milkweed plants, but there were plenty in the area and the potential for more with the removal of some small trees.

As Joe had said, there were great opportunities for restoration here. The milkweed meadows are already part of a larger area designated as special habitat, so they would not be commercially logged but should be well suited for restoration. An old grassy road going through the middle of the area from the north might make it accessible for restoration work. Now one of my next goals is to go farther up that road to another set of openings to see if the milkweed continues up the ridge. Can’t wait to see what else we’ll find!

2 Responses to “A Week of Monarchs and Milkweed: Day 1”

  • Kristy Swanson:

    This is great news. They are the The Classic butterfly. I have several milkweed plants growing in my yard in case any monarchs fly by and check us out. I’m going to move them to a spot where they can expand their territory. I’d forgotten what the caterpillars look like.

  • Have lots of blooming milkweed – speciosa – but as of yesterday no monarch activity. Have had considerable for the last several years. We are in the Dundee Hills in the Willamette Valley.

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