Date: 09/07/2018

Number: 50000

A massive wave of monarch butterflies moved through Clearville Park today. Today the skies were cloudy, temp 70 F with light North-East Wind. The conditions today were excellent for focusing the butterflies to travel along the Lake Erie shoreline in a SW direction. There were so many butterflies it was almost impossible to count them. There were some butterflies dropping to the ground looking for nectar but the vast majority where gliding on the wind well above tree height. Many were up 2 or 3 times tree height – and many more were much higher, gliding on the wind. At one point, there were so many the sky was a black cloud of butterflies against a cloudy-sky background. I conservatively estimate 10-15 thousand per hour passing through from 12:00 noon until 5:00 PM. Unfortunately I didn’t have my camera with me. If we have a repeat of weather conditions in the next few days with a northeast wind (the key factor) I’ll be sure to have my camera.

When the wind is from the north east it forces the butterflies to fly along the shore-line which concentrates them in large numbers. This is a pattern I have seen in previous years which is why Clearville Park is a good place to see the migration provided the wind cooperates. They don’t like to go over water unless they have to. They prefer to fly in a south- west direction because if you continue in that direction it will take you to Mexico.

September 10 addition: Pt. Pelee is 50 miles due south-west of Clearville Park on the Lake Erie shore so is in the direction that the butterflies are flying. Pt. Pelee is the southernmost tip of Canada and is a National Park. Monarchs form large roosts there waiting for weather conditions to take them across the lake to Ohio. Because of the number of butterflies that we witnessed on Friday (9/7) at Clearville Park they should start showing up in large numbers at Pt. Pelee in a few days. It will take a few days because the weather after our sighting on Friday has been dominated by the remnants of Tropical Storm Gordon with very strong 40 MPH east winds so it is unlikely that they would make any progress in such poor conditions. The weather conditions are expected to improve tomorrow (9/11).

Muirkirk, ON

Latitude: 42.5 Longitude: -81.7

Observed by: Steve
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