Those Migrating Monarchs

Birds which migrate vast distances each year have long been a marvel to interested observers—but even more marvelous is the migrating butterfly, danaus plexippus, commonly called the Monarch butterfly.

Monarchs travel up to 3,000 miles every fall. Those moving south from the eastern two-thirds of the United States and Canada predominantly head for a small forest in central Mexico, where millions of these beautiful creatures annually congregate in a remote mountain area comprising less than 15 square miles. Some thirteen million of them annually congregate in just one particular site only three to four acres in extent!

Smaller colonies winter at locations along the Gulf Coast from Florida to south Texas, while Monarchs from the western third of North America mostly winter in small areas along the Pacific coast, between San Francisco and Los Angeles. Smaller numbers over-winter in Arizona. Additionally, “the Monarch has spread from its home in the Americas to Hawaii, Indonesia, Australasia, the Canary Islands, and has recently established colonies in Mediterranean countries.”

But the most amazing thing about this annual migration is that every one of the migrating millions are on a first-time, one-time journey. They have no experienced leaders or scouts, and they start from thousands of locations spread across a large continent; yet year after year the current generation will zero in on one small target area—truly a mass demonstration of remarkable navigation! In their wintering grounds, they will cover the trees in a shimmering restless blanket of orange-and-black beauty, throughout the winter months.

When April signals their time of departure, the Monarchs will wake from their stupor and mating will take place. “It is mostly fertilized females that migrate north. Most will die after laying their eggs; only about one percent of these travel all the way to northern states, laying eggs as they go.” Following these generational leaders will be a growing horde of males and females rapidly matured from the eggs laid earlier. Thus for most Monarchs it will take at least two generations to reach the summer feeding grounds.

Monarchs primarily feed on milkweeds, which are poisonous to other creatures, so they stop to feed where milkweeds are plentiful—and there they lay their eggs. The eggs will hatch into hungry caterpillars, which will feast upon milkweed leaves for several weeks before entering the chrysalis stage. Then, within a week or two, an adult Monarch will struggle out of the chrysalis husk, and after its wings dry and harden, it is ready to feed—and, shortly, to mate again and die.

Normally, one or two additional generations will exist briefly before the final, longer-lived migratory generation arrives to finish the journey. Somehow they will know their route and their destination. Scientists have determined that Monarchs’ wings do contain slight amounts of magnetite, an iron compound which they speculate may give the butterflies an orientation with the earth’s magnetic field—but as their destinations are spread across thousands of miles from east to west, there would be huge differences in their individual “compass headings.”

Man may wonder about the influence of prevailing winds and ask whether insects can navigate by the stars, but the surest and best answer is that the Creator who made them has given them all that they need to survive as a species. God said in the beginning: “To every beast of the earth, and to every fowl of the air, and to everything that creepeth upon the earth, wherein there is life, I have given every green herb for meat” (Gen. 1:30). And again the Bible acknowledges: “O Lord, thou preservest man and beast” (Ps. 36:6).

God has given man the intelligence to discover some of the workings of this great world which He fashioned for us, and it is good to learn His ways after Him. But it is far better to learn this truth from the Bible: “The eyes of all wait upon thee (O God), and thou givest them their meat in due season. Thou openest thine hand, and satisfiest the desire of every living thing” (Ps. 145:15-16).

Truly, the God who implants the necessary knowledge in the Monarch butterflies also cares for us. The Son of God, Christ Jesus, declared: “Are not two sparrows sold for a penny? And not one of them shall fall to the ground without your Father. But the very hairs of your head are all numbered. Fear ye not therefore, ye are of more value than many sparrows” (Matt. 10:29-31).

The Old Scot (Ted Kyle) lives in Newberg, Oregon, with his wife, Marga.

References:
David Carter, Butterflies and Moths, Dorling Kindersley, NY, 1992, p. 184.
Donald and Lillian Stokes/Ernest Williams, The Butterfly Book, Little, Brown & Co., Boston, Toronto, 1991, pp. 88-91.
World Book, 2005 ed., I10, p. 296.
Valerio Sbordoni and Saveria Forestiero, Butterflies of the World, Crescent Books, NY, 1984 [English translation 1985], various pages.