Date: 09/08/2020

Number: 50

Started noticing them arriving yesterday afternoon. By evening numbers are at least 50. Still hanging out there today. Mid 50s temperature and raining. Photo isn't great, tried to take through the binoculars.

I first saw them arriving in a silver maple tree in my backyard on Monday afternoon, about 4:00. I counted about 15 or so fluttering around and landing in the tree within about 30 minutes.

About 6:30 I saw that they were still coming. So I got out my binoculars and watched til it got too dark to see. Probably about 7:30. I counted up to 50 that I could see with the binoculars by scanning around looking at the several branches they seem to cluster together on.

I know there were probably more because I could see some flying into adjacent trees. My house is on a bit of an elevation compared to the surrounding area. It isn’t a protected area at all really. I’d say it’s actually the tallest tree on maybe the highest point in the immediate area. It is a low traffic neighborhood though, as far as Sun Prairie goes.

Temperatures are pretty consistent with what my iPhone weather app reports. Generally it’s been high temps in the mid 50s with on and off steady rain all day 9/8 and 9/9. The evening they arrived 9/7 temps were dropping and winds were picking up.

They were still there as of today (9/9/20).

The only nectar sources I can think of around would just be typical yards in the area. I’m working on my own property putting in native plants. But my stuff isn’t in bloom yet, except my sunflowers are in bloom now I did plant some asclepias tuberosa in the front and we got 7 caterpillars and only one made it into butterfly form. It eclosed the same day the roost arrived and its still sitting out there. Like it’s too cold to move.

I am relatively certain they did this in the same tree last year, as I saw a swirl of butterflies fly up in the tree and disappear. But I didn’t know what I was witnessing at the time.

Sun Prairie, WI

Latitude: 43.2 Longitude: -89.2

Observed by: Melanie
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