Date: 09/27/2019

Number: 2000

They Roosted at Great Gull Island, NY for the last week

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

The roosting monarchs I saw were on Great Gull Island, NY. It’s a small 17 acre island that is The American Museum Of Natural History’s Research Station in Long Island Sound. It is the site of one of the largest Tern colonies in the world. They cover it with guano and that helps a large crop of Milkweed and Golden Rod....I’ve worked there seasonally for 40 years and saw my first Monarchs roosting there then (about 50) on a cold autumn evening (on a privet bush). We often leave the island on Labor Day, but the last few years I’ve been out to the end of September. If you're on Facebook at all, I have a page: My View From Great Gull Island that has photos of the island and wildlife etc.

Last year I found a couple of small roosts on the island and kept my eyes out this year for them roosting. In September the island is covered with Monarchs, on the 16th this year I found lots of small groups all over the west end of the island (groups of 3-10 ) on Goldenrod. I also found a small roost of about 30 on the now huge Privet.
The next day the group was on the privet but also noticed some in the pine grove close by. Numbers went up and down the next few days but very large group on Saturday the 21 (estimate a thousand plus). The next day most seemed to leave the island and Sunday the 22 was very sparse in the trees (a few hundred). It was a week of good wind, the Monarchs roosted in the downwind side of trees. I have video of them also hanging on to the pines in a squall with heavy wind and rain. I'll post it on My View From Great Gull if I already haven’t.
The biggest number of about 2000 was on the 27

What time of day did you observe this roost? ROOST OBSERVED JUST BEFORE SUNSET TO SUNSET AND AGAIN IN MORNING AT SUNRISE, THEY LEAVE THE ROOST WHEN THE SUN HITS THEM.

How did you arrive at 2000 adults? SAME AS I DO FOR FLOCKS OF BIRDS- COUNT 10 THEN COUNT BY 10 TO 100 THEN COUNT BY HUNDREDS.

Were there any nectar sources nearby, and if so what? ISLAND IS COVERED WITH GOLDENROD AND OTHER WILDFLOWERS

What was the overnight temperature for the date you observed them?COOLER BUT NO IDEA OF TEMPS.

What was the wind direction? Were the monarchs shielded from the wind in this location? WINDY MOSTLY FROM NE,N,and NW, THEY TOOK SHELTER IN THE DOWNWIND SIDE OF THE TREES.

To see photo and video, check out my FB page My View From Great Gull Island: https://www.facebook.com/pg/thatisland/photos/?ref=page_internal

Great Gull Island, NY

Latitude: 41.2 Longitude: -72.1

Observed by: Matthew
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