Date: 09/14/2020

Number: 200

At least 200 monarchs roosting in several trees: maple, birch, and pine.

The roost was not on my property. The homeowner said they had noticed them the day before, which would have been Sept. 14. She said there were more butterflies on the 14th than when I was there on the 15th, but she did not attempt to count them. She also said this was the third consecutive year they have seen a roost in their yard.

I observed them from 2:30 to 3:00 p.m. on Sept. 15, then again at about 6:00 p.m. There were fewer butterflies at 6 than there were at 3, which was not what I expected.

I tried to count the butterflies in one of the lower clusters (28) and took it times the number of clusters I could see (5). I rounded up to 200 because the clusters higher in the trees were much larger than the cluster I counted. There were also lots of butterflies that were resting in other trees, but not gathered in a group.

Roughly 75 yards south of where the butterflies were roosting, the homeowners have about an acre of prairie restoration and it was awash in goldenrod.

Overnight low temperature was 57 degrees on the 15th, 55 degrees the night before. There was a light SSW breeze (12 miles an hour)
The monarchs were shielded from the wind. There was a row of evergreen trees (I think they were spruce) just north of the maples that the monarchs were in.

Pella, IA

Latitude: 41.4 Longitude: -92.9

Observed by: Wendy
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