by Victoria R. Schmalhofer
Invasive species – let’s call them “invasives” for simplicity – are plants or animals (or other organisms) that, having been transported – sometimes deliberately, sometimes accidentally – to a region where they were not previously found, thrive and eventually outcompete, displace, consume, or otherwise negatively impact and cause the decline of native species. Two key features define invasiveness: the species is non-native in the region of concern, and the species has widespread negative impacts on native organisms in its new habitat.
Invasives provide a cautionary tale of how easily “inadvertent migration” can be accomplished. Brown tree snakes (which have devastated bird populations on Guam) were accidental arrivals transported on the landing gear of aircraft. Zebra mussels (affecting the Great Lakes and tributary rives) arrived in the ballast water of cargo ships. Both the emerald ash borer and Asian longhorn beetle (impacting various tree species) arrived in shipping pallets (the wood used to make the pallets had not been sufficiently kiln dried to kill the beetle larva). With accidental introductions, it is difficult to know precisely when an invasive arrived in its new home. The first record of the species in the new region permits establishment of a general time frame of arrival, but the invasive may have been present for some time before it was observed and its presence noted.
Even in the case of deliberate introductions (and there have been many of these!), the exact timing of establishment is often not known. Multiple introductions of the species may have occurred, and it is generally not known which of these efforts were successful.
Occasionally, however, we do know . . . . . with great precision.
Such is the case of the European starling, which was released into New York’s Central Park on March 6, 1890.3
The release of starlings, and their subsequent meteoric rise to invasive status, has been the subject of much debate and some controversy2,3 – but is it all much ado about nothing?
The tale, though tragic and somewhat speculative, is an interesting one that offers up much for our consideration. Like all good tragedies, the foibles and follies of the players are obvious in hindsight.
The antagonist in this drama is one Eugene Schieffelin (1827-1906)9, a “gentleman of means” who lived in New York City. In the nineteenth century, it was common for men whose wealth permitted them significant discretionary leisure time, to spend that time partaking of activities offered by various social clubs. These clubs often had a scientific orientation. Schieffelin, an amateur ornithologist, was a member of multiple such organizations.9 His membership in the American Acclimatization Society9 (of which he was the chairman)6 is the most relevant for the purposes of this tale. Acclimatization societies were very fashionable in those days, and their purpose was rather startling (from a modern perspective): the deliberate introduction of non-native species to new environments for the express purpose of naturalizing those species in the new region.8 Why this was done is a moot point. Whether it was for scientific curiosity (Can these species thrive here?) or because immigrants waxed nostalgic for the flora and fauna of their (or their forebearers’) natal homeland, the end result was the same: the establishment of non-native “exotic” species in North America. (The exchange of species went in the opposite direction as well, with North American species being introduced to other continents.)
Thus far, the facts of the tale are not in question. Records show that: Schieffelin was an amateur ornithologist9; he belonged to several scientific societies9; he was the chairman of the American Acclimatization Society3 in New York City; the purpose of the acclimatization society was the introduction of European plants and animals to North America8; Schieffelin imported and released European species in and around New York City2,3,9; European starlings were one of the species he imported and released.2,3,9
At this point, however, the tale takes a twist that is difficult to prove (or disprove), as contemporaneous records are lacking. The twist involves a singular question: why? Why starlings? There are approximately 900 species of birds native to Europe – why did Schieffelin choose starlings?
As the story goes, Schieffelin was a great devotee of Shakespeare and conceived a plan to establish in North America every bird mentioned in the collected works of the Bard.2,3,9 In addition to starlings, Schieffelin attempted to introduce bullfinches, chaffinches, nightingales, and skylarks.3,9 Does this lend credence to the Shakespeare argument? Possibly. All these species receive a mention in one or another of Shakespeare’s writings. As supporting arguments go, however, it should be taken with a rather large grain of salt: Shakespeare mentions 60 some species of birds in his plays and poetry. Fortunately, the bullfinch, chaffinch, nightingale, and skylark introductions failed9 . . . .
But I digress – back to the story of the starling!
Starlings receive a single mention in Shakespeare’s Henry IV, Part 1.5 In act one, scene three, Harry Percy (nicknamed Hotspur), the son of the Earl of Northumberland, fantasizes about engaging in a little psychological warfare with the king. (Hotspur and his father are in rebellion against Henry.) Hotspur toys with the idea of giving the king a starling that has been trained to repeat the name of one of Henry’s foes (starlings are mimics, so this is plausible):
I’ll have a starling shall be taught to speak
Nothing but Mortimer, and give it him,
To keep his anger in motion.5
And so, according to the legend, the stage was set for starlings to come to America.
In 1890, Schieffelin imported 60 European starlings – and another 40 in 1891 – releasing the birds into New York’s Central Park.2,3,9 The birds not only lived, they thrived and multiplied and in short order had spread well beyond the bounds of the park. Today, European starlings are found from coast to coast throughout the entire continental United States, and much of Canada as well.7 Starlings are gregarious birds and flock in massive numbers (those huge flocks, that fly as though in synchrony, are called murmurations). They have (allegedly) contributed to the decline of many native North American bird species by displacing native species from suitable habitat.
Starlings are an excessively abundant species, to be sure, and one that is not native to North America. But do starlings actually merit the appellation invasive species? Here I refer to the technical, ecological criterion for an invasive species: a non-native species that becomes abundant in its new habitat, disrupting community dynamics and displacing and/or causing the decline of other species. Starlings have been implicated in reductions in yellow-bellied sapsucker populations (the two species nest in hollows in trees and compete for nest cavities), but interactions between starlings other species are less clear.2 Things are likely not as cut-and-dry as once thought, and the reputation of starlings as an egregious invasive species – while perhaps not a scurrilous calumny of Shakespearean proportions (no one can sling insults like the Bard!) – may not be entirely deserved.
And to be fair to Schieffelin as well, he was not the only person to release starlings into the wild.2,3,9 He does, however, appear to be the first (and only) one to establish a viable breeding population of starlings that has persisted.10 Interestingly, starlings were also released in Portland, Oregon, at approximately the same time (1889 and 1892) as the New York release.4,10 Though the Portland introduction was reported as successful, starlings disappeared from the region around 190010 and were not seen again until the 1940s.4 While it is possible that the “march of the starlings” across the North American continent involved spread from both coasts inward, not a sweep from east to west, the genetic structure of North American starlings does not refute a single New York origin model.10
Whether Schieffelin’s selection of starlings was impelled by his love of Shakespeare is an open question. Though Schieffelin’s admiration for the writing of Shakespeare is generally accepted, whether that admiration influenced his importation choices – as opposed to some other consideration, such as which bird species might be better at suppressing pest insects – is, and will remain, a matter of speculation.
Starlings coast-to-coast is not quite the end of the story, though. Or, more accurately, the tale of the starling has a prequel. As it turns out, Sturnus vulgaris may not have been Schieffelin’s first acclimatization success. He has the dubious distinction of – perhaps – also being (partly) responsible for the establishment of a second invasive species, the house sparrow. In 1860, some thirty years prior to the start of the starling debacle, Schieffelin was involved in a release of house sparrows.3 However, given that it is unclear whether the introduction was successful, and the fact that there are at least 22 recorded instances of house sparrows releases across the United States between 1852 and 18811, blame for the current status of house sparrows as an invasive species in North America cannot be laid on Schieffelin’s shoulders.
The mid-to-late 1800s was a sort of “wild west” time in the biological subdiscipline that would eventually become ecology. Species were moved around the globe willy-nilly with complete disregard for geographic boundaries. Establishing beneficial “exotic” species in new environments (one of the goals of the acclimatization societies popular at the time) was a means of harnessing the power of nature for the betterment of humanity, and little (if any) thought was given to the possibility of unintended consequences. If a species was aesthetically pleasing or perceived to have practical benefit, it was a candidate for importation. “Invasive species” was not term anyone used, and no one considered the potential for “naturalized” species to wreck environmental havoc.
Though we now have a better grasp of the hazards inherent in moving species around the globe, deliberate introductions still occur.
Perhaps a little more humility and a little less hubris in the face of Nature is in order. History has proven some of our actions (in the not so distant past) to have been wildly misguided (cane toads are a classic example). As the Bard said: “The fool doth think he is wise, but the wise man knows himself to be a fool.”6
- Barrows, WB. 1889. The English sparrow (Passer domesticus) in North America, especially in its relation to agriculture. US Department of Agriculture. Division of Economic Ornithology and Mammalogy. Bulletin 1. pp 422.
- Bittel, J. 2022. The Shakespearean tall tale that shaped how we see starlings. New York Times, April 11, 2022. (accessed February 22, 2024)
- Lamb, J. 2016. What if we had all the birds from Shakespeare in Central park? JSTOR Daily, published June 9, 2016. (accessed February 22, 2024)
- Link, R. 2012. Starlings. Living with Wildlife. Washington Department of Fish and Wildlife. (accessed February 23, 2024)
- Shakespeare, W. 1597. Henry IV, Part 1. Act 1, Scene 3 (Hotspur’s musings).
- Shakespeare, W. 1623. As You Like It. Act 5, Scene 1 (Touchstone’s reply to William).
- Sibley, D. 2014. The Sibley Guide to Birds. 2nd ed. Alfred A. Knopf, New York.
- Wikipedia, “acclimatization society.” https://en.wikipedia.org/wiki/Acclimatisation_society (accessed February 23, 2024)
- Wikipedia. “Eugene Schieffelin.” https://en.wikipedia.org/wiki/Eugene_Schieffelin (accessed February 22, 2024)
- Zichello JM, DeLiberto ST, Holmes P, Pierwola AA, Werener SJ. 2024. Recent beak evolution in North American starlings after invasion. Scientific Reports 14:140, doi.org/10.1038/s41598-023-49623-y