Spectacular Fall Migration Witnessed in Texas
October 10, 2004
A river of Monarchs passed over today. The passage lasted probably 5 hours, with a 2-3 hour peak, and it was at least a couple kilometers wide with, therefore, thousands per hour. I wouldn't be surprised if there were 100,000 that passed!
This was mostly observed from my home, 5 kilometers northeast of Utopia, Texas, but we ranged southeast as noted.
By noon I had seen a few Monarchs in the yard, passing south (S) to southsouthwest (SSW).
By 1 pm I had seen about 6-8 monarchs. At 1:30 I saw 5 at once, and grabbed my binoculars and started scanning.
Standing at one end of my porch, between 1:32 and 1:37 I was counting 100 per minute. All were going S to SSW. They were everywhere. Up 100 feet high, in groups, thermalling.
I walked around trying to get a vantage point from the bowl we're in and, for a half hour, anywhere you looked you saw a hundred as fast as you could count them. A hundred a minute. I would look east, and count a hundred within one binocular field of view, within a quarter mile, and it was the same to the west behind me. Between 2:10 & 2:30 it seemed to slow to 50 per minute in every direction.
It seemed to me that ten thousand passed at minimum in the hour, and it was likely twice that, or more. (This was a slice of a kilometer or so width, of a mass of butterflies of unknown width.)
So we headed to town (Utopia) 5 km SW. All along the way the river continued in density as fast as you could count them (100/minute approximately). The town was full of them, but shortly after getting north of town they decreased rapidly. There were only small numbers of them at Lost Maples Scientific and Natural Area later in the afternoon. However, back here at the adobe, at 6:30 p.m. they were still going over to the SSW at the rate of 10 per minute.
This leads me to believe they continued in high numbers here (after I left), for some time. They were not further north in the valley, and were clearly coming into the Sabinal River Valley from the NE, mid valley or so.....
Anyway, some settled in and are roosting, so there should be a liftoff tomorrow (Monday, October 11).
The passage lasted probably 5 hours, with a 2-3 hour peak, and it was at least a couple kilometers wide with, therefore, thousands per hour. Considering most were early in the afternoon, I would expect they made if off the escarpment already, only 10 miles south. I wouldn't be surprised if there were 100,000 that passed!
Contributed
by Mitch Heindel
Utopia, Texas
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