Date: 09/15/2019

Number: 1000

Estimated over 1000 roosting that evening in Aspens, amazing! Feeding on Goldenrod during the day. Tagged 100 in short order

Editor's note: contacted observer for more details on this sighting

It has been a wonderful season for monarchs! I have tagged them the last four years, usually going out on 4+ occasions and lucky if I get 60 tags completed. This year it took me 3 short visits to tag 100 and I could've done lots more.

When did the roost first form? I visited the Badger Prairie park on 9/11 around 3pm and saw several hundred flying and feeding on goldenrod (tagged 25 in less than an hour). I did not witness the roost that day. On 9/13 there was a post on Facebook from a gentleman that said hundreds were roosting at the park at 5pm. Hi Temp that day was 70F, evening low 57F.

The only evening I witnessed the roost was 9/15, it was muggy and calm, temps were 74F, evening 64F. I returned to the park on 9/17 and the goldenrod was past peak and I didn't see many monarchs, far fewer than 2 days prior.

How did you estimate 1000? There were at least 10 clumps of monarchs, each clump with at least 100. When guessing again, I would say there could've been 3000. The trees were filled with monarchs and this was just one area of the park ( Badger Prairie park is about 300 acres). We witnessed the roost around 6:45 pm, after sunset, when it was getting pretty dark so it was pretty difficult to see how many were in the trees. Also, the gentleman (from the Facebook post) saw the monarchs at a different part of the park, if they were there as well, then this park probably had 4000!

The roost I saw was in a treeline at the southern end of the park, winds were SW at 5mph (data taken from weather underground). The treeline is not very protected but not very high up either. See video below.

One other thing: On 9/20, as I was supervising the playground about 1 mile from Badger Prairie park, we saw a pretty constant stream of monarchs heading south - in an hour we saw 35 monarchs (the kids loved it). Wind was SSE at 1mph, temp 84F

Madison, WI

Latitude: 43 Longitude: -89.5

Observed by: Joan
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