NATURE NOTES FROM ACADIA

THE MONARCH BUTTERFLY IN ACADIA

A monarch among its kind, the Monarch Butterfly has quickened the hearts of innumerable nature lovers. Perhaps its majestic flight and bearing gave rise to its name; but the possession of scent pouches or scent glands, which are supposed to protect it from its enemies, and its migratory habit are responsible for most of the interest in it. For both are unusual characteristics among our butterflies. Its extraordinary migrations have been the subject of many printed pages.

None were seen in 1931 when the writer came to Acadia National Park. Local observers stated that the Monarch had been very rarely found here due to the absence of its food plant. In 1932 one or two individuals were seen. In 1933 a number of specimens were seen or captured. Now in 1934 it has increased until six to eight may be seen at a time feeding in a patch of thistles or goldenrods.

The life history of the Monarch Butterfly is most interesting. It feeds on milkweeds in the larval state. The butterflies which migrate northward in the spring of the year place their ovate tapering eggs on the milkweed leaves. The caterpillars are yellow and green with narrow transverse bands of black. They have long fleshy black processes arising from near each end. To many people they are unusually interesting and attractive, but some people who have not watched their interesting transformations think they are repulsive worms. When fully grown the caterpillar spins a pad of silk from which the chrysalid will hang. The caterpillar skin splits open and is pushed off. A lovely pea-green chrysalid with golden spots remains. In this vault-like structure great changes take place; soon the shroud splits open and a monarch comes forth to spread pinions which will bear it for hundreds or even thousands of miles. Lack of milkweed plants prevents its breeding in this locality. We see it slowly drifting from flower to flower sucking the nectar in preparation for its long journey.

The Monarch feeds on the nectar of thistles, goldenrods, and many other flowers. As fall approaches it begins drifting southward. From the many patches of milkweed in Canada and the Northern States little groups are formed, and later as the migration becomes more marked large flocks collect. These roost in a body on one or more trees, and they have been known to cover the leafless trees as thickly as the recently fallen leaves did. The individuals seen in Acadia have drifted here from the mainland to the northward. After feeding for a time they will move on to join the swelling flock which are moving southward. Due to the conformation of land and water, lines of migration converge in places and great numbers of individuals pass through some sections such as the north shore of Long Island and the coast of New Jersey. The acrid or nauseating qualities of their scent pouches are believed to protect them from birds and other predators. In the spring battered Monarchs move northward out of the Gulf States. They may be the ones which went south in the fall or they may be their offspring - no one knows. Searching for milkweed plants on which to lay their eggs they fly northward. At this season the direction of their movement carries them inland and they are rarely seen in Acadia; however a few were seen last spring. The reason for the great increase in the number of Monarchs coming to this region is probably that the species has greatly increased of recent years. Its kind is at flood tide. May its numbers long swell like the breakers which roll up on Acadia's granite shores.

- Dr. A. E. Brower
Asst. State Entomologist
Maine Forest Service

A Word Further Concerning the Monarch. - In an article entitled, "Our Butterflies Invade England," which appeared in The New York Times for September 30, 1934, mention was made of the Monarch and a few other American butterflies which had been observed in England. In this article the entomological expert of The Times of London, writing of the Monarch, remarks as follows:

"'It is a commonplace of American natural history that this insect, habitually and in great numbers, makes migrations of hundreds of miles over the land. The ocean is another matter, and it was at one time supposed that the very occasional specimens noticed here must have been carried most of the way by ships.

"'Now, however, it is no longer doubted that his own motive power conveys the Monarch to our shores - across 1,500 miles of watery waste! The question may be held to have been settled by the experiences of 1933.'"

- A. S.