The Urbanization of the Eastern Gray Squirrel in the United States
I feel like I've blogged about this before, but here it is again, so I can reference it more easily as part of my research of Boston Common:
The Urbanization of the Eastern Gray Squirrel in the United States
Etienne Benson Journal of American History, Volume 100, Issue 3, December 2013, Pages 691-710, https://doi.org/10.1093/jahist/jat353 Published:
01 December 2013
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Arriving
Given the present ubiquity of gray squirrels, it may be difficult to believe that they have not always been common in American cities. In fact, they seem to have been entirely absent during the first half of the nineteenth century. The lack of systematic surveys before the twentieth century hinders estimates of the size of historical squirrel populations, which can fluctuate dramatically from year to year depending on food supplies, weather conditions, and other factors. Even indirect measurements can be elusive. Information that would allow the mapping of urban vegetation, including nut- and acorn-bearing trees, is exceedingly sparse for periods as recent as the turn of the twentieth century. Nonetheless, using biological findings as a source of bounds on plausibility, it is possible to draw some rough conclusions about population and presence on the basis of newspaper reports, scientific studies, historical photographs, diaries, and other sources. On the whole, these sources suggest a dramatic expansion of the number and range of urban squirrels in the second half of the nineteenth century due to three interacting factors: human efforts to foster urban squirrel populations, changes in the urban landscape, and the squirrels’ efforts to adapt and thrive.4
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The dominant image of the eastern gray squirrel in early nineteenth-century American culture was as a shy woodland creature that supplied meat for frontiersmen and Indians and game for the recreational hunter but could also become a pest in agricultural areas. Although some other members of the squirrel family, such as the American red squirrel (Tamiasciurus hudsonicus, also known as the pine squirrel), were present in eighteenth- and nineteenth-century American cities, and although small numbers of gray squirrels could be found in woodlands on urban fringes, the gray squirrel was effectively absent from densely settled areas. Sometimes called the “migratory” squirrel, the species was known for unpredictable mass movements by the thousands or even millions across the rural landscape. In The Winning of the West Theodore Roosevelt wrote of the eighteenth-century American backwoodsman’s fight against “black and gray squirrels [that] swarmed, devastating the cornfields, and at times gathering in immense companies and migrating across mountain and river.” Crop depredation by gray squirrels-Roosevelt’s “black squirrels” were merely a color variant of the species-led residents to set bounties and carry out large-scale squirrel hunts well into the nineteenth century.5
The only gray squirrels found in urban areas during this period were pets, such as Mungo, memorialized by Benjamin Franklin in a 1772 epitaph, who escaped from captivity and was killed by a dog after surviving a transatlantic journey to England. In most cases such pets had been taken from nests while young, and many were probably abandoned, killed, or had managed to escape after they matured. Nonetheless, they provided opportunities for urban Americans to form opinions about the habits and character of squirrels that complemented and sometimes contradicted those opinions formed in the context of hunting and farming. Pet squirrels, for example, which were widely available from live-animal dealers, were not shy like the wild squirrels in areas where hunting was common, and they often became importunate in their search for food in pockets and pantries. Familiar within the home, these pets appeared exotic and out of place when they escaped into the urban environment. In 1856 the New-York Daily Times reported that the appearance of an “unusual visitor” in a tree in the park near city hall had attracted a crowd of hundreds; until they were scattered by a policeman, the onlookers cheered the efforts to recapture the pet squirrel.6
The first introductions of free-living squirrels to urban centers took place in cities along the Eastern Seaboard between the 1840s and the 1860s. Philadelphia seems to have been the pioneering city, with Boston and New Haven, Connecticut, following soon after. In 1847 three squirrels were released in Philadelphia’s Franklin Square and were provided with food and boxes for nesting. Additional squirrels were introduced in the following years, and by 1853 gray squirrels were reported to be present in Independence, Walnut Street, and Logan Squares, where the city supplied nest boxes and food, and where visiting children often provided supplementary nuts and cakes. In 1857 a recent visitor to Philadelphia notedthat the city’s squirrels were “so tame that they will come and take nuts out of one’s hand” and added so much to the liveliness of the parks that “it was a wonder that they are not in the public parks of all great cities.”
Boston followed Philadelphia’s example by introducing a handful of gray squirrels to Boston Common in 1855, and New Haven had a population of squirrels on its town green by the early 1860s.7 The people who introduced squirrels and other animals to public squares and commons in Philadelphia, Boston, and New Haven sought to beautify and enliven the urban landscape at a time when American cities were growing in geographic extent, population density, and cultural diversity. A typical expression of the motivation behind this effort can be found in an 1853 article in the Philadelphia press describing the introduction of squirrels, deer, and peacocks as steps toward making public squares into “truly delightful resorts, affording the means of increasing enjoyment to the increasing multitudes that throng this metropolis.”
In Boston the release of squirrels on the Common was the project of Jerome V. C. Smith, a physician, natural historian, member of the short-lived Native American party, and Boston’s mayor from 1854 to 1856. Smith’s decision to have Vermont squirrels released on Boston Common was interpreted even by his critics as an attempt to “augment the attractions” of an increasingly leisure-oriented public space. For George Perkins Marsh, the author of Man and Nature, the tameness of the squirrels of the Common was a foretaste of the rewards to be expected when man moderated his destructive behavior toward nature. Like the planting of elms and other shade trees in cities and towns across the United States, the conversion of town commons and greens from pastures and spaces of labor into leisure grounds, and the creation of quasi-rural retreats such as Mount Auburn Cemetery (established outside Boston in the 1830s), the fostering of semitame squirrels in urban spaces aimed to create oases of restful nature in the industrializing city.8
As habitats for squirrels, Philadelphia’s public squares, Boston Common, and New Haven Green were indeed oases: isolated refuges offering water, shelter, and food in the middle of an urban desert. The fifty-acre Boston Common was the largest of these areas, but even it, comprising mostly open fields and bordered on one side by the marshy tidal flats of the Charles River and on the other by dense commercial and residential settlement, was capable of supporting only a limited number of squirrels. By the summer of 1856, a year after they were first introduced, the squirrels of the Common appeared to be thriving and even expanding into the neighboring Granary Burying Yard, but there is no evidence that they were able to range beyond these public spaces into nearby residential or commercial areas. In the winter, the squirrels left their summer nests in the Granary Burying Yard and retreated to the Boston Common nest boxes, tree holes, and city-provided food (which cost Boston $33.27 during the years 1856-1857). An 1863 proposal to plant nut-bearing trees to relieve the burden on the city’s coffers may have been made in jest, but it suggests that food sources besides those directly provided by humans were scarce. The English elms could have provided edible seeds and buds for a brief time in the spring, but on the whole the vegetation in the Common provided sparse squirrel food and virtually nothing that could be stored for the winter months.9
Whether the Boston squirrels actually faced a shortage of food, or of sufficiently nourishingfood, is unclear. In NewHaven, at least, this seems not to have been the case, judging by an 1865 report that the squirrels of New Haven Green had “become so obese from good living that they are continually missing their hold and falling from the tree tops.” Nonetheless, any undernourishment or malnourishment might have led the squirrels to adopt otherwise-unusual food habits, such as eating birds and their eggs or stripping bark from trees. Some of Boston’s and Philadelphia’s residents opposed the introduction of squirrels, fearing that they would prey on songbirds and their eggs, and indirectly cause an increase in insect populations. In 1855 a pseudonymous writer for the Boston Evening Transcript denounced the introduction of squirrels as an “absurd and reprehensible experiment” likely to lead to damage to trees and other plantings once the squirrels had exhausted birds as a food source. In Philadelphia such concerns led the city to request the advice of the Committee on Entomology of the Pennsylvania Horticultural Society, which concluded in 1864 that even though there was no evidence of squirrels eating birds or disturbing nests, the likelihood of squirrels having some negative effect on birds was high, since both species resided in trees.10
Following the issuance of the entomological committee’s report, Philadelphia’s squirrels were captured or killed, their nest boxes were removed, and the city made an attempt to establish insectivorous European and American songbirds in their place. Boston’s experiment with squirrels also came to an end around 1864 or 1865, though it is unclear whether the cause was concern about birds and insects, plain neglect, or the use of Boston Common as a military exercise and mustering ground during the Civil War. According to the former Boston mayor Nathaniel Bradstreet Shurtleff, writing in 1871, the squirrels simply died out. Even on New Haven Green, where a small squirrel population seems to have survived, by 1865 dogs were reported to have killed all but eight squirrels out of a population that had at one point reached as many as fifty.11
The gray squirrel populations of Philadelphia, Boston, and New Haven were vulnerable to intentional or accidental eradication in the 1860s because their small populations were almost entirely dependent on human provision of food and were unable to expand beyond the confines of the public spaces to which they had originally been introduced. Female eastern gray squirrels usually begin breeding in their second year of life and under exceptional circumstances can give birth to two litters per year, with each litter averaging about 2.5 young. The species’ high reproductive potential means that under favorable conditions an initial population of one or two dozen squirrels can explode into hundreds or even thousands within a few years. Once grown, young squirrels, especially males, can disperse a mile or more from their natal sites in search of new nesting areas, food resources, and mates. Thus, squirrels could rapidly move into newly available urban habitats, although actual rates of colonization were slowed by various factors, and some introductions failed entirely. In American cities in the 1850s and 1860s squirrels had little chance of surviving outside of parks and public squares.12
The conditions of existence for squirrels in American cities improved significantly from the 1870s onward, in large part due to the landscape park movement led by Frederick Law Olmsted. Compared with public squares, commons, and town greens, Olmstedian landscape parks provided much larger and more suitable habitats for squirrels, while also bolstering the justification for introducing and maintaining them. For urban reformers of the time, squirrels and other animals helped enliven urban green spaces and contributed to a bucolic atmosphere that was entertaining, enlightening, and salubrious. The gray squirrel was seen as a particularly desirable park resident, since it was understood to be, as the naturalist John Burroughs would later write, an “elegant creature, so cleanly in its habits, so graceful in its carriage, so nimble and daring in its movements,”and one that“excites feelings of admiration akin to those awakened by the birds and the fairer forms of nature.” Urbanites who encountered such admirable creatures living in the middle of the metropolis would, reformers hoped, be projected into a more wholesome and natural world, if only for a moment. Once landscape parks had been constructed in New York, Boston, the District of Columbia, Chicago, and other cities, it was only natural to populate them with squirrels. These populations ultimately served as the foundation for the dissemination of squirrels throughout the urban landscape.13
New York City was at the forefront of this development, inaugurating a second and ultimately much more consequential phase of squirrel introductions to urban areas, including, eventually, to cities such as Seattle and London, which were well outside the native range of the gray squirrel. (In some North American cities a behaviorally similar species, the fox squirrel [Sciurus niger], was introduced alongside or instead of the eastern gray squirrel.) In 1877, just a few years after the official completion of Central Park in accordance with Olmsted and Calvert Vaux’s 1858 Greensward Plan, the staff of the Central Park Menagerie released a handful of gray squirrels, flying squirrels, and chipmunks in the Ramble, a wooded “wild garden” of about thirty-eight acres located roughly near the center of the park. The population of gray squirrels was supplemented the following year by an additional thirty pairs. By 1883, just six years after the first release, the park’s gray squirrels had expanded in number and range to the point that the menagerie’s director, William Conklin, told the press that he was considering a cull to reduce their impact on the park’s trees, which the squirrels had stripped of leaves and small branches to make their nests.14
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The urban parks movement provided a set of protected enclaves large enough to harbor substantial squirrel populations and capable of serving as sources of surplus squirrels that could expand into neighboring residential areas, which were becoming increasingly amenable to squirrels. After Boston reclaimed marshy land along the Charles River to create the Back Bay neighborhood in the late nineteenth century, for example, numerous trees were planted along the Charles River Esplanade and Commonwealth Boulevard, creating new habitats that squirrels from the Common could colonize with the help of food boxes stocked by neighborhood children. The tree-lined streets of New York City’s Upper East Side and the northwest quadrant of Washington, D.C., similarly provided habitats into which squirrels could extend their range from core populations in parks, at first only seasonally but eventually year-round.17
On the outskirts of the city, the growth of streetcar suburbs during the late nineteenth century often involved the conversion of farmland into small lots with single-family homes surrounded by gardens and trees and in close proximity to new suburban parks. On farmland, squirrels had been seen as pests or game and had been trapped or shot on sight, but in residential suburbs they were often protected and fed and sometimes provided with nest boxes. The resulting geographical expansion began to weave the squirrel populations of parks, common areas, and public squares into connected metapopulations that were resilient to local extirpations of the kind that had eliminated Boston’s and Philadelphia’s squirrel populations in the 1860s.18
Two other examples may make clear how the expansion of squirrel populations throughout the urban landscape resulted from the interaction of human introduction and protection, changes in the urban landscape, and squirrels’ reproductive and dispersal efforts. The first comes from Cambridge, Massachusetts, where the ornithologist and lifelong Cambridge resident William Brewster closely observed the growth of gray squirrel populations from the 1890s to the 1910s. According to Brewster, who published “Squirrels in Cambridge”in Harvard Graduates’ Magazinein 1912, it took about a decade, starting in the early 1890s, for gray squirrels to make their way from Mount Auburn Cemetery at the western edge of the city to the densely settled area around Harvard Square, a distance of a little more than a mile. This advance, he noted, had been facilitated by the change in the landscape of West Cambridge from large estates and orchards, where squirrels had been shot as pests (by his own father, among others), to smaller residential lots, where they were tolerated and even welcomed. In 1900 an acquaintance of Brewster who had surveyed the city’s trees as part of an effort to eliminate nonnative gypsy moths told him that gray squirrel populations were growing in all of Boston’s suburbs, while populations of red squirrels were declining. These gray squirrels had not been intentionally introduced, at least not on any large scale. Instead, they had migrated from wooded areas at the fringes of the city into habitat that had recently become capable of supporting them and to which they were capable of adapting with the help of human residents. Among those who aided this colonization process was Brewster, who regularly fed the squirrels that began nesting in his yard in the mid-1890s.19
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Gray squirrels also thrived in New York, Boston, Philadelphia, Chicago, and many other cities and towns from the late nineteenth century onward not only because they received food, shelter, and protection from the cities’ human residents but also because they took advantage of the changing urban landscape and built environment in ways that their new human neighbors had neither planned nor necessarily desired. Attics and spaces within walls offered nesting sites that exceeded even the best tree holes for security against predators and the elements. Human food waste provided a year-round source of nourishment that partly made up for the paucity of nut-bearing trees in many locations. Telephone and electric power lines provided security from dogs and cats and facilitated transit across the increasingly crowded, busy, and dangerous city streets. As early as 1902 Harvard University’s squirrels were described as running “along the telephone cables, high in air, at lightning speed, something like tightrope walkers, when pursued by barking dogs.” The offspring of squirrels that had learned to exploit a new food source, route, or nesting site often incorporated those discoveries into their own behavioral repertoires. The nuts and nest boxes offered by squirrel lovers were crucial to the establishment of squirrel populations in American cities, but the persistence and growth of those resilient populations depended on the squirrels’ adaptation to an environment that had little in common with the woodlands where they had evolved.22
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The provision of food and nest boxes for squirrels became a way for institutions and individuals to demonstrate publicly their commitment to an expanded vision of urban community, even if they did not share all of the convictions of the most enthusiastic urban-squirrel advocates. The administrators of many city parks and college campuses, who had sometimes been responsible for introducing squirrel populations, placed nest boxes in trees and provided squirrels with peanuts and other food sources, particularly during especially harsh or snowy winters. In the first years of the twentieth century, Harvard University built nest boxes for squirrels in the elms of the college yard and distributed bags of peanuts over the winter, as did the authorities in Central Park, Boston Common, and many other city parks and squares. In 1902 the superintendent of Mount Auburn Cemetery assured one concerned lot owner that her unsolicited donation of $6 for winter squirrel feed was appreciated but unnecessary, since “not only the squirrels but the pigeons, crows, and sparrows as well, are all regularly fed and cared for.” With relatively little effort or financial outlay these institutions were able to demonstrate a commitment to pleasant, civil, and lively public spaces.24
...In 1914 both the Animal Rescue League of Boston and the Massachusetts Society for the Prevention of Cruelty to Animals distributed food to the squirrels and birds of Boston Common during the winter months. ...
Nonetheless, the practice of feeding squirrels was not confined to children, women, and older men. It became popular among students on some college campuses, and newspaper features about beautiful days in the park mentioned the feeding of squirrels by all genders, classes, and ages. Feeding was undoubtedly entertaining to many, but it also allowed urban residents to demonstrate their generosity toward the needy. The headline of a Boston Globe article about Thanksgiving on Boston Common in 1908 put it this way: “Beggars, Squirrels, Birds-All Remembered.” Because of the presence of urban squirrels, even the least powerful members of human society could demonstrate the virtue of charity and display their own moral worth. Gray squirrels helped reshape the American urban park into a site for the performance of charity and compassion for the weak, providing a nearly ideal opportunity for the extension into public spaces of what Katherine Grier has called the “domestic ethic of kindness to animals.” 2
This is one of the sources for this paper, I just love the title: “Thanksgiving Cheer Evident among All Classes. Beggars, Squirrels, Birds-All Remembered,” Boston Daily Globe, Nov. 27, 1908