Monarch Butterfly Migration Over Central Iowa in Fall 2000
By Robert D. Woodward
During the summer of 2000, the monarch butterfly activity in central Iowa appeared to be down considerably from previous years. In our butterfly garden, sightings of monarchs were less frequent----unlike years when one might see 10, 20 or more passing through the garden on a single day.
August 28--A flurry of monarch activity late in the afternoon seemed to indicate the migration of the butterflies was under way. Fifteen or more monarchs were sighted in the afternoon, including five in the butterfly garden.
August 29--The weather became unseasonably warm, and the flow of monarchs subsided in the wake of the heat. That situation would prevail for several days thereafter.
September 4 (Labor Day)--Few monarchs were seen this morning at Chichaqua Bottoms wildlife area in northeast Polk County, Iowa. Three migrating monarchs were observed flying high and fast to the south with the wind. A single monarch was sighted resting on a bush. The dry conditions were illustrated by an old riverbed in the wildlife area; it often contains 6- to 8-feet of water but now was nearly dried up.
September 5--Five to 10 monarchs were spotted in our butterfly garden in the late afternoon, and they were finding the purple asters that were now beginning to bloom.
September 8--The monarch migration picked up considerably on this Friday afternoon. In and around our butterfly garden, approximately 75 monarchs were sighted--feeding on the asters and goldenrod, finding water, resting on the branches of oak tree limbs, and floating gently in the afternoon breeze. One monarch spent nearly an hour feeding on a single goldenrod flower.
September 9--A strong wind from the south southwest diminished the monarch movement to the south. During an hour of observation at Chichaqua Bottoms wildlife area, two monarchs were observed resting on tree branches, sheltered away from the southerly wind. A third monarch struggled against the wind as it sought to move from one point to another in the area. Back in our butterfly garden in Altoona, Iowa, perhaps 15 or more monarchs were hanging around the protected areas--presumably having stayed there from the previous day. The wind during the day was 15 miles an hour or more, with gusts in the 30 mph range.
September 10--A visit to Chichaqua Bottoms wildlife area in the early morning did not turn up many monarchs. But after 10:30 a.m., in our butterfly garden, the migrating monarchs began coming at a quickening pace, and, indeed, a major migration was under way--with more than 200 monarchs flying in and around the garden over the next three hours. Our house sits in the northern section of the old part of Altoona, and the open prairie is just a few blocks away. The monarchs could be spotted coming in from the north, flying anywhere from 3 feet to 100 or more feet off the ground. They were stopping to feed on the purple and pink asters, the phlox, and the goldenrod--and to get a drink of water. For the first time this fall, some repeated a pattern observed in past years of beginning to glide from 50 to l00 feet above--and then landing directly on flowers in the garden. Four monarchs followed one after the other just as if they were airplanes landing at a busy airport. Later in the afternoon, late arrivals could be seen flying around the butterfly garden, feeding, and resting on tree limbs.
September 11--A spectacular of nature occurred late Monday afternoon in the skies over central Iowa. The day's temperature had tied a record high at 97, and a cold front was passing through from the northwest to southeast. At approximately 4:30 p.m., migrating monarch butterflies could be seen in the sky floating on the wind, their shadows showing sharply against the clouds above. As the wind picked up in intensity, monarchs could be seen flying high and quickly, floating speedily on the wind, or being pushed to the east by the windy conditions. Above our butterfly garden in Altoona, Iowa, approximately 100 monarchs were counted in about 40 minutes from 5:20 p.m. to 6 p.m. as the cold front passed through the area. Many of the monarchs could be seen only through binoculars while others could be seen with the naked eye as their shadows showed on the clouds above. It was a riveting event and displayed the extremes of weather through which the monarchs must pass as they make their way southward to Mexico.
September 12--The weather cooled down from 24 hours earlier, and occasional monarchs could be seen throughout the day crossing the roadways and, at the end of the day, entering the butterfly garden to feed.
September 13--Minimal monarch activity was observed--only an occasional monarch. The day's temperature shot up again, going over 90 degrees. The question is whether or not the major days of migration through central Iowa have occurred.
September 14--Early morning thunderstorms moved through the central Iowa area, and cooler weather was once again on the way. Perhaps the cooler weather will bring another wave of monarchs from the north.
September 15--The day started quite early as I made a 165-mile trip to western Iowa and the beautiful loess hills, an area where I grew up in earlier years. A harvest moon was hanging over the countryside, and as the sun rose later in the east, the glory of a wonderful autumn day could be seen across the landscape. During the day in the loess hills and the Missouri River Valley, perhaps 15 monarchs were counted at the most. The monarch migratory season clearly appears to be winding down in Iowa. In the drive back to central Iowa starting about 4 p.m., not a single monarch was seen along the Iowa roadways. The national Annenberg and CPB site has taken note of this journal for those who are interested in learning more about ways in which to track monarch movements.
September 16--The day started quite cool with temperatures reported in central Iowa ranging from 39 to 46 degrees. Certainly if monarchs are still around, they will be moving south today. But a drive on central Iowa's secondary roadways over several hours turned up only five migrating monarchs.
September 17--Only a single monarch was observed during an hour visit to Chichaqua Bottoms wildlife area in Polk County. The monarch was feeding on Jerusalem artichoke flowers and clover--and was moving ever so slowly to the south. The dry conditions certainly may have been playing a part in the monarch activity in the summer and fall. The old riverbed at Chichaqua is the lowest I have seen it in years. It's lower than a week ago, two weeks ago. Carp--some of which appear to be in the 8- to 10-pound range as their backs protrude from the shallow waters--can be seen struggling in the narrow rivulets and water pools left in the riverbed. Back home in the butterfly garden later in the day, five monarchs were counted in the afternoon, including two that spent at least two hours feeding on the tall purple asters.
September 18--Three monarchs were seen during the day, which had heated up again to the 90-degree range. Two of the monarchs were in the butterfly garden in the late afternoon.
September 19--No monarchs were observed.
September 20--One monarch was observed.
September 21--Much cooler weather flowed into central Iowa. The temperature at 5 a.m. was 40 degrees. By mid-morning, a few monarchs were on the move again, and several friends told of seeing monarchs in threes and fours. With my observations included, at least 20 monarchs were seen during the middle of the day--feeding on flowers and moving to the south.
September 22--The day was cool in the early morning, and a rain fell across central Iowa for several hours. But in the afternoon, three monarchs were observed in our butterfly garden, feeding for more than an hour on the purple asters.
September 23--No monarchs were observed.
September 24--The day was cool, and rain fell in the early morning. At one point in the early morning, the wind chill index was at 37 degrees, and the temperature was in the low 40s. A visit to Chichaqua Bottoms wildlife area confirmed what I suspected: No monarchs were migrating through the area. No monarchs were seen throughout the day in our butterfly garden.
September 25--No monarchs.
September 26--Despite the cool weather and rain over the last several days, a single monarch showed its colors in our butterfly garden late in the afternoon. The monarch spent considerable time feeding on the purple asters.
September 27--One monarch was observed flying across a roadway.
September 28--A shadow on the ground called my attention to a monarch in the air on the campus of Drake University. The monarch's shadow has become a familiar and wonderful way for me to see monarchs over the years. Many times I have first been alerted to a monarch's passing by seeing a shadow on the ground. This day, I saw three monarchs--the last one feeding on purple asters in our butterfly garden in the late afternoon.
September 29--The weather warmed up again. The temperature hit a high of 80 degrees in central Iowa, and a brisk wind was blowing. In our butterfly garden, five monarchs spent the afternoon feeding on the asters and resting on the branches of walnut trees in the front yard.
September 30--The day was sunny and warm, but a strong wind was blowing from the south. No monarch movement was observed.
October 1--A single monarch was spotted on the Iowa state fairgrounds in Des Moines, reminding me of last year when the last monarch I saw during the season was observed at the fairgrounds--in late September.
October 2--No monarchs were observed.
October 6--No monarchs were seen throughout the week, and this morning, the temperature dipped to 32 degrees at 6 a.m. It seems unlikely that many more monarchs--if any--will be observed this autumn.
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