Date: 09/11/2015

Number: 481

Larry Gehres and I observed 481 monarchs migrating at Harrisville State Park at the shoreline of Lake Huron. We observed that the monarchs were coming EAST off the lake and heading due West. They were flying high from 50 to 200 feet as they came off the lake. We could see them quite far out as they approached. Instead of landing on the beach as they usually do, they just kept on going west with fast and steady wing beats. The monarchs did this for most of the 10 hour count. Inland, the wind was NW at 7 mph, but it was northeast off the lake at 10-14 mph.

We believe that the monarchs actually crossed Lake Huron from Canada. If they came from the Bruce Peninsula area of Canada, directly due east of us, it would take at least 6 hours to cross on a good NE wind on steady wing beats. 

Alternatively, maybe they had been blown over the lake from somewhere to our north and were working their way inland. The northeast winds may have been hitting the northwest wind near the beach, so maybe the monarchs were flying from the north and got pushed out over the lake and then pushed back to land coming from the east.

Temperature at the start of the count was 57F. with a high of 64F. It was 59F. at the end of count. Very fluffy clouds, but plenty of sunshine.

Here is the hour by hour count:
9-10 AM - 15
10-11 AM - 17
11-12 AM - 30
12-1 PM - 28
1-2 PM - 50
2-3 PM - 80
3-4 PM - 55
4-5 PM - 80
5-6 PM - 97
6-7 PM - 29
Total- 481 Last year on 09/16/14- 606

Harrisville, MI

Latitude: 44.6 Longitude: -83.4

Observed by: Frank
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