Monarch Butterfly Migration Over Central Iowa
Fall 2009

By Robert D. Woodward

 

A monarch butterfly chooses an autumn favorite--the tickseed sunflower

 

September 1--The monarch butterfly migration is under way across central Iowa. On this day, the sky was mostly clear, the weather was cool, and the number of monarchs differed sharply from two previous days over the weekend. In two hours and 40 minutes, we counted 251 monarchs at Neal Smith national wildlife refuge near Prairie City, Iowa. They primarily were nectaring on tickseed sunflowers, the favorite wildflower for monarchs this time of the year. Cool weather to the north--38 degrees overnight at one point in northern Iowa--appeared to have contributed to the speeded-up monarch movement.

September 2--During an afternoon visit to Neal Smith refuge, 110 monarchs were observed in one hour and one-half. Once again, the monarchs were nectaring primarily on tickseed sunflowers. They were racing to and fro among the wildflowers in the north part of the refuge.

September 3--This was an amazing day for observing the migration of monarch butterflies at Neal Smith national wildlife refuge. During two and one-half hours of counting in the morning, we saw 526 monarchs. They were continuing to visit the stands of tickseed sunflowers, and they were putting on a wonderful display of their colors against the yellow background of the flowers.

September 4--As the days go by, monarch butterflies will begin to spend their time on other wildflowers, but in the early days of the fall migration, they continue to favor the tickseed sunflowers. That pattern continued this Friday at Neal Smith refuge. During two and one-half hours of observations, we counted 307 migrating monarchs. Most of them were nectaring on tickseed sunflowers, but on one hillside a number of them were stopping to feed on the goldenrod on their way south.

A stand of tickseeds is a great attraction for migrating monarchs

 

September 5--Monarch butterflies are continuing to be on the move over the prairie at Neal Smith national wildlife refuge. In the northern part of the refuge, a large stand of tickseed sunflowers has been attracting the monarchs as they fly south over the Iowa farmland and approach the wildlife refuge. This morning, a visit to the heart of the stand turned up 160 monarchs in 20 minutes as they moved from flower to flower. Overall, the count of monarchs was 332 during two hours-plus of observations at the refuge.

September 6--The tickseed sunflowers continue to be a major attraction of migrating monarch butterflies at Neal Smith national wildlife refuge. The counts being conducted are along roadways in the refuge, but the stands of tickseeds are everywhere across the Neal Smith prairie. One wonders what the counts would be in the many inaccessible areas. During three hours of observations, 368 monarchs were noted on this day.

September 7--The weather continued to be sunny and cool, the breeze was light, and the day provided another excellent environment for the migrating monarch butterflies at Neal Smith national wildlife refuge. In two and one-half hours of observations, we counted 470 monarchs thus illustrating a consistency in the strong numbers being noted this autumn. Overall, 2,364 monarchs have been counted at the refuge in the first seven days of observations.

September 8--The strong numbers of monarchs continued for another day at Neal Smith national wildlife refuge. The weather once again was highly favorable for monarch activity. During two hours of observations on a cool and sunny day, we counted 340 monarchs.

September 10-13--We made a round trip through southeast Iowa, on to St. Louis and then returned. We were hoping to judge the monarch migration activity along the roadways, but unlike some other years of observations, we saw just a few monarchs along the way. The weather was cool and sunny for the most part. This year, monarch movement over the highways in central Iowa and beyond has been minimal in relation to other years.

September 15--During the first visit to Neal Smith national wildlife refuge in a week, we noted how the number of migrating monarch butterflies had declined. We counted 91 monarchs in one and one-half hours. The landscape, too, was changing as the days of autumn passed. The tickseed sunflowers, which had been the favorite stop for the monarchs this fall, were going to seed so the butterflies were turning to the taller sunflowers.

September 17--Only four monarchs were noted during a one-hour visit to Neal Smith national wildlife refuge.

September 19--Two monarchs were observed in our butterfly garden in Altoona during the day. One was nectaring on a bright red zinnia.

September 20--No monarchs were observed during a 50-minute visit to Neal Smith national wildlife refuge. In our butterfly garden, two monarchs were seen during the day.