Date: 09/17/2025

Number: 12

1856 Hours

12 monarchs in two clusters on a common hackberry (Celtis occidentalis), both clusters on southwest side of the tree, 4 meters above the ground. One cluster had 8 monarchs on one branch, and a nearby branch had the second cluster with 4. Monarchs were observed flying along trees along the trail for a quarter to half mile. They would stop, then continue flying. Some single monarchs were observed in other trees roosting, but they were not added to this count. The monarch activity was at its highest 15-20 minutes before the sun went down on horizon.

At sunset. 76 degrees (24.44 C). Sun has set on the horizon. Very light winds at 3 mph with gusts up to 5 mph from northeast. Wind is picking up as the sunset, but still somewhat light. RH 61%, Dew Point 62. Sunset at 1857.

On Henslow Trail near at Midewin National Tallgrass Prairie (U.S. Forest Service).

Wilmington, IL

Latitude: 41.4 Longitude: -88.1

Observed by: Mike
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