Ecologically speaking, the most dangerous guests are the invasive species—the insects, animals, and plants that arrived here by accident, or simply through bad judgment, and stayed.

Unfortunately, there are thousands of these unwanted guests now—pests responsible for billions of dollars of environmental damage each year. Here are two of these invaders.

Wandering Gypsy Moths

The gypsy moth is a classic example of an invited pest that is here to stay. It arrived on North American shores because of one man’s desire to become wealthy in the silk industry.

Etienne Léopold Trouvelot (1827–95), a native of France, professional painter, and recognized amateur entomologist, had moved his family to Medford, Massachusetts, in 1852. It is believed that he received some gypsy moth specimens in the mail in 1868.

Credit: Kirsanov Valeriy Vladimirovich/Shutterstock

Hoping to crossbreed the gypsy moth with the mulberry silkworm, he began cultivating them in a shed on his property—some seven or eight treed acres, most of which he had under netting. Eventually, he released some gypsy moths to feed on the foliage of his trees. Somehow, some larvae got away from him (some records suggest that wind carried them away) and thrived because of the lack of predators and parasites. Not until 20 years later did local residents realize that it was these nonnative moths that were defoliating and destroying their fruit and shade trees and thus began to look for ways to exterminate the pests.

Today, gypsy moths are established in all of the northeastern United States and portions of the Southeast and Midwest, plus portions of eastern Canada. Efforts to eliminate them have been under way through the USDA Forest Service and on local levels.

Credit: Joseph Sohm/Shutterstock

The Bard’s Birds

Eugene Schieffelin (1827–1906), a German immigrant and drug maker living in New York City’s Bronx borough, was consumed by two great passions: Shakespeare and birds. By some accounts, it was Schieffelin’s former interest that inspired a pursuit of the latter and would eventually land him a dubious standing in the annals of history: importer into North America of every bird species mentioned in the plays of William Shakespeare (64 in all). Not coincidentally, Schieffelin was chairman of the American Acclimatization Society, whose members’ stated goal was the introduction of species.

Some of the Bard’s birds did not survive in their new home, but one line from Henry IV spoken by Hotspur gave Schieffelin some hope: “I’ll have a starling shall be taught to speake nothing but ‘Mortimer’ … .”

Thus, on the morning of March 6, 1890, Schieffelin and a few of his servants entered Central Park and released 60 starlings from their cages. These birds, some sources claim, made a beeline to the American Museum of Natural History and set about building nests under its roofline (starlings seek out cavities for nesting, often bullying native birds for space). The following year, Schieffelin released 40 more starlings. It is believed that of those freed, 16 pairs ultimately survived.

Image: Menno Schaefer/Shutterstock.   Swarms, aka murmurations, of starlings.

Today, starlings are one of the most populous avian species in North America (estimates run to 200 million)—and, by many accounts, the most problematic.

Wintering flocks of starlings mingle with blackbirds and cowbirds and create enormous problems: They eat feed grain, blueberries, cherries, and other pitted fruits, as well as apples. They consume suet and seed in residential bird feeders, depleting the resources available to smaller birds.

If a lot of starlings (among other birds) roost in the same location, their droppings can contaminate the soil, resulting in fungal spores that can become airborne and, when inhaled, cause histoplasmosis, a respiratory illness. Swarms, aka murmurations, of millions of starlings are hazardous to air travel.

Have you had any experiences with gypsy moths, starlings, or other invasives?  Please share below.