This news just in from Dr. William Calvert, a monarch specialist and entymologist who is studying major monarch migration flyways through Texas.
April 1st First sightings near San Angelo, Texas and repeat-sightings in the Richardson/Garland area, just north of Dallas. A large group was also sighted near Port Arthur, Texas apparently headed into Louisiana.
March 31st Monarchs continue to flood up the coast of Texas. They have been sighted as far north as Dallas and as far east as Woodville, which is within about 50 miles of the Louisiana border. They have not been sighted in the west or extreme north yet. Almost all the sightings have been coming in from the coast, which is why there have been no sightings in west Texas. They are spreading out towards Florida. Monarchs have been flying straight into a very strong north wind which has been blowing for the last 5 days. Some days the wind has been blowing 25 knots! (See "Windly Flight" activity below.)
Nature Notes from Dr. Calvert: Everything has leafed out in Texas except the pecans. There are quite a few different species of milkweed that can be found in Texas. The three most common are the Tubarosa or butterflyweed, the Virdis, and the Asperula or staghorn weed. There have been quite a few sightings of (monarch butterfly)eggs on the milkweed. Dr. Calvert thought that eggs would begin to be sighted in late March but now knows that it happens eariler.
Dr. Calvert's Research With the help of a network of volunteers across the state, Dr. Calvert discovered two flyways in Texas during last fall's migration: One, by far the largest, was about 250 miles wide and was centered along a line from Eagle Pass through Abilene, straight from Oklahoma. In his words, "Reports of the migration through this area from late September to mid-October were unequivocally massive. In places around Uvalde, Brackettville and Del Rio, awesome is a more appropriate word to describe the monarch passage. Only a little less spectacular was the migration along the Gulf Coast from High Island to Corpus Christi. Perhaps the most remarkable discovery is that the flyways are very distinct. We need to observe the monarch migration for an additional number of years to determine just how fixed the flyways are and to what extent they meander from year to year."
Another part of Dr. Calvert's research monitored the monarch's direction of flight (called the "vanishing azimuth"). Take a look at a map of Texas and Mexico and see if you can make sense of his preliminary observations: "Butterflies in inland areas of Texas fly southwest at about 216 degrees, those along the coast fly more westerly at 236 degrees, and those at Victoria, Mexico fly parallel to the mountain axis at 168 degrees."
A report of a monarch sighting came from the Miami, Florida, area on March 29th. How can this be explained? Read the possibilities below and send your ideas to: wildadv@iubvm.ucs.indiana.edu
1) The monarch over-wintered in Florida. (According to monarch specialist Dr. William Brower, monarch wintering colonies have been known in Florida. He doesn't know of any colonies this year, and says the long-term viability of surival of such colonies is not secure, because Florida temperatures fluctuate every few winters below which monarchs can live. This is why the colonies in Mexico are critical to the survival of eastern North American's monarch butterflies.)
2) The monarch flew across the Gulf of Mexico. (Calculate the distance this butterfly would have flown to Miami from the monarch wintering colony near the town of Angangueo, Michoacan, Mexico-west of Mexico City. Compare it to the dates and locations of the sightings in Texas. Does it seem possible that the butterfly could have crossed the Gulf of Mexico and reached Miami by this date?
3) The observer was mistaken or playing an early April Fools' joke.
Windy Flight Courtesy of Cassy Ordway
Materials String cut into 20' lengths, leaves or pieces of paper with a hole pierced in the center.
With students holding the string at both ends, put the leaf at one end with the string through the hole. Let the wind carry the leaf to the other end. What happens when you turn the string at different angles to the wind? Try different size leaves. What happens? Try two leaves at the same time. What happens? How would the wind affect a butterflies migration? Look at the wind patterns over the Gulf of Mexico. Do you think that monarchs can fly all the way across the Gulf? This spring, let's pay attention to the monarch sightings on Journey North and see if any butterflies got blown off course and were sighted in an unusual area.
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