[Ctleps-l] Monarchs and other Migration, 10/10

[Steve Walter]

It was an unusual day yesterday in that I planned on, and in fact did, go
hawk watching and doing my moth survey in the same day. In the fall, it's
different weather conditions that are favorable for those two endeavors.
October days with winds from the northwest, but 80 degrees with good enough
humidity are kind of rare in the northeast. But so it was yesterday. My
ongoing moth survey is at Jamaica Bay Wildlife Refuge. To make that feasible
and to limit travel, I chose Fort Tilden for the hawk watch effort. That
site is on the Rockaway peninsula, toward the western end of the Long Island
coast. 

 

Well before the hawks got going in modest numbers, it was evident that one
kind of migration was happening at a not so modest clip. That was the
Monarch migration. I never actually count them, and it was obvious there
were too many on this day to get bogged down counting one by one. I ran into
Doug Gochfeld, who was more infatuated with the event than I was. He seemed
to have a system where he did periodic minute counts, from which he could
extrapolate a total number (or estimate). The first time that I saw him do
that he got 60 in a minute. Later on he was getting counts that got up to
around 150, and finally a peak of 170. Below is his summation to me in a
personal e-mail, followed by a more detailed post to the New York State bird
list. To add to that, the Monarchs were still going strong for three hours
after he left. I'm not inclined to calculate how many that might have been.
Even if the rate slowed down, I think it's safe to say that well over 50,00
Monarchs passed through Fort Tilden yesterday.

 

What I will also add to that is that it seems rather late for such a huge
flight. My recollection, which was shared by Doug (from his days of doing
the hawk count at Cape May) and Don Riepe, was that Monarch migration peaks
around the third week of September. Changing times? The Osprey count
yesterday was 63, which is a lot for so late. Moth night, among other
things, included my latest ever underwing (The Sweetheart - Catocala
amatrix). 

 

Another butterfly migration note. Obvious southbound migrants are Red
Admiral and Question Mark. While these are October migrants, few of these
were seen yesterday. While Common Buckeye, American Lady, and Painted Lady
clearly migrate northward, I can't say that I'd ever seen anything to
convince me  that they migrate back to the south. In most years, there
aren't enough Pained Ladies to work with. So what about in this banner year?
I have to say that were quite a few around yesterday and most of the ones
that I saw moving, were going in the right direction. The fly so low, and
that makes it unclear if that's really the intent. But Ryan MacLean,
covering the Quaker Ridge (Greenwich) hawk watch yesterday, did tell me that
he saw a couple flying high over the watch.

 

Steve Walter

Bayside, NY 

 

 

>From Doug Gochfeld:

 

"As for Monarch numbers, I ended up getting to just barely over 35,000
(35,150), counting up all of my rates. This leaves a gap of 35 minutes when
I wasn't counting (and Monarchs were going over the Fort proper, away from
the beach at a few a minute at minimum). So probably safe to say in the
38,000 range from 0800 to 1415. I arrived around 0715, but only saw 2
Monarchs before 8 AM when the floodgates seemed to open a bit. The wind
gaining intensity definitely correlated with a big increase in concentration
and speed of the flight."

 

 

"However, the obvious highlight of the day was the massive westbound

movement of Monarch Butterflies. An almost three hour vigil atop the

Battery Harris platform yielded approximately 4,000 of these, quantifying

it based on many minute-long counts taken throughout the morning. This all

came after 8:00 AM, when the flow started as if a faucet was turned on, and

ended around 10:00 AM. The wind was almost nonexistent early, and this

likely contributed to them being spread out north to south, and also moving

quite slowly to the west. I then headed over to the fisherman's lot to the

west to see if there were Monarchs in the abundant Seaside Goldenrod there,

even though the flow had appeared to lessen at that point.

 

When I got over to the Fisherman's Lot, however, the flow was much thicker,

and we peaked at a steady rate of 170/minute for 20 minutes or so, and over

150/minute for almost three hours (including those aforementioned 20

minutes), before slowing down to the 110/minute range, and then scaling

back even more as the wind shifted more to the west, which probably made

the flight much less concentrated. It was one of the more phenomenal

migratory movements of any animal that I've ever seen in the state. As for

total Monarch numbers, from the notes of the rates I was taking throughout

the day (until I left at 2:15 PM), I reckoned that I saw just about 35,000

Monarchs heading west. Given a 40 minute gap in my counting, it would be

safe to say that 38,000-40,000 Monarchs passed through Fort Tilden through

2:15 PM.

This never-ending ribbon of Monarchs through the dunes was truly
astounding."

 

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