Date: 09/19/2019

Number: 800

Saw many hundreds (maybe a thousand) roosting in a friend's neighbor's stand of pine trees. They said they've been there for three days (heavy rainstorms with some sun). Mostly gone as of 9/20/19.

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

The monarchs were roosting in my friend's neighbor's yard starting on Tuesday, Sept. 17th. She saw monarchs flying around on the 16th but the roost was discovered on the 17th in the afternoon. I observed the roost on Thursday, Sept. 19th (the photo submitted with this report was taken that day). They roosted in those trees until Sunday, Sept. 22nd according to my friend.

As far as number estimation on my Sept 19th observation, there are 3 or 4 conifers in her back yard, each about 50 feet tall, with 2 or 3 branches per tree covered with monarchs. So if there were 200-250 butterflies per tree, that would be between 600 and 1000 butterflies. However, my friend reports that her observation on the evening of the 17th had probably twice the number of monarchs that I saw on the afternoon of 19th, with many on lower hanging branches.

Interestingly, there were other types of conifers immediately adjacent to the roost but no monarchs on those...they clearly preferred this particular type of conifer!

We observed one mating pair on Sept 19th afternoon as well.

We aren't aware of nectar sources nearby however this is a residential neighborhood with lots of flower gardens. I personally have a small pollinator garden in my yard, 1/4 mile away, but only saw an occasional monarch floating through my yard.

Here are overnight low temps and 24H max wind speeds. The wind direction was generally SE on most of these days, lots of rain, and yes, the trees and houses provided protection from the wind.
Sept 17 (all early mornings temps): 69F/17mph
Sept 18: 69F/17mph
Sept 19: 70F/15mph
Sept 20: 67F/15mph
Sept 21: 73F/20mph
Sept 22: 66F/ 16mph

After sharing my photos on FB, a friend mentioned that on Sept 8, they released 1,000 monarchs for a hospice fundraiser probably 3 or 4 miles away. Not sure if they were tagged monarchs but we didn't see any tags (not that we would necessarily know what what to look for).

Finally, my friend's neighbor emailed these details about their departure on the 22nd: "The butterfly departure was in full swing on Sunday afternoon following the rain. They started by spreading their wings to dry out and then there were a few test flights. By evening the butterflies were nearly all gone after the cooler temperatures and the light winds arrived."

Link to more photos on Snapfish: https://www.snapfish.com/library/share?via=link&token=i3yw3JuBvglZIN2VqLoj0g/AUS/27950553514070/SNAPFISH

Waterloo, IA

Latitude: 42.5 Longitude: -92.4

Observed by: Kelly
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