Early Migration

By Georgia Sparling | Sep 02, 2016
Artwork by: George B. Emmons

By George B. Emmons

As Earth on it’s axis slowly rotates the face of the northern hemisphere away from the direct rays of the Sun, the haunting refrain from the 1950’s popular song “the days grow short when you reach September" is sentimental for back to school children and vacationing adults. But the diminished hours of daylight are also harbingers for wildlife creatures of our gardens and woodlands already motivated by record heat and drought while long shadows of autumn handwriting are clearly on the wall for departure.

First affected by drought is the amphibious spotted salamander, whose vernal pools have already dried up where they came in soaring across local roads to reproduce at the same site of their own origin. As cold blooded creatures, gradually their body temperature turns as cold as the air temperature with lack of food forcing an exodus, reversing their migration back to the starting point of a moist Earth winter refuge.

Similarly motivated is the aquatic egg laying dragonfly that in spring deposited its eggs in the stem of a plant at the water’s edge. The larvae emerged with beautiful transparent wings able to fly as fast as a moving car and catch large quantities of mosquitos. With a rapid back and forth wing movement they are often called darning needles with this industrious action and are also able to mate in midair. Before a first frost kills their food supply they must begin their long journey south, traveling from pond to pond. Those that leave will not come back but their progeny will, a generational necessity of many migrating insects.

The monarch butterfly is perhaps the most iconic migrant insect, flying several thousand miles from Canada to Mexico, often stopping in the same rest areas we annually witness and celebrate along the Atlantic coastal flyway. Females will lay eggs along the way back, also sowing the seed of a generational procreation to complete the journey. However, to migrate the same mountain tops in Mexico and back again is a mysterious navigational miracle, partially explained by using the Sun as a compass and magnetic fields for guidance along coastal landmarks with a prevailing wind.

Amazingly the large yellow underwing moth also migrates, but at night using the Moon for reference instead of the Sun, and a shorter cross country distance from garden to garden and meadow to meadow, out of our sight and with only progeny returning. The more visible hummingbird is possibly the most endeared figure as a daily acrobatic phantom at our nectar feeders also eating insects and spiders as long as they last. With good reason, but unannounced, one morning they are also gone without even saying goodbye.

As days fly by with migrants past our windows, it is a September song whose planetary meaning is written in the stars.

 

 

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