We often hear complaints that there are "too many" Canada geese, they are "overpopulated" and must be managed. These claims are not supported by science.
Overabundance is defined as a state or instance of going beyond what is proper or needed. Overpopulation is a scientific term used by biologists when a species exceeds its biological carrying capacity (the maximum number of individuals in a species that its habitat can support). We may say that there is an overabundance of soft drinks or an overabundance of lawyers, but we don't debate about an overpopulation of soft drinks or an overpopulation of lawyers. Overabundance is subjective and dependent on the observer, creating always the element of observer bias. At any given time, a sampling of a multitude of parks, golf courses or ball fields can appear overabundant with geese or any other species, but this does not signify necessarily overpopulation. The American Passenger pigeon (Ectopistes migratorius) was the most numerous bird on earth in the 1800's--its flocks numbered in the millions with nesting sites miles long. Within 40 years, it was extinct. Its biological carrying capacity was compromised by man through loss of habitat, and it was slaughtered on a scale second only to that of the American bison (Bison bison). Despite its staggering numbers, it was never allowed to reach true overpopulation, and by all accounts from that period, was never killed solely because it was "overabundant." Like the migratory Passenger pigeon-though to a much lesser extent-Canada geese (Branta canadensis) depend on a high population density for protection and survival; high numbers in flocks (birds), herds (ungulates) and schools (fish) is a selective advantage for many species as a communal defense against predation, nesting and brooding success, climatic change, and feeding efficiency. But the threshold of human tolerance - the social carrying capacity of a species - is relative to time and place. One observer viewing a locality with many geese may think "there are too many geese around," whereas another will perceive it as a special moment: "....An impressive example of establishing a population of this race [Branta canadensis maxima - the giant Canada goose] in an area of dense human population (Lake St.Marys, Ohio) has been described by Karl Bednarik (letter, November 22,1963) '...Our geese nest in the islands...just about any place you can imagine. The human residents around the lake take great pride in having free-flying geese nesting on their property....'" (H. Hanson, The Giant Canada Goose, 1997).
All animal populations have an unlimited capacity to increase their numbers, yet never realize fully their reproductive potential because of the many limiting factors peculiar to each species--both from without (interspecific) and within (intraspecific) the population. Because of a favorable habitat in the United States with its large expanse of open land and a plenitude of cultivated grain crops for foraging, and with its traditional predators now imperiled or the targets of government eradication programs themselves, the resident Canada geese population has increased substantially since its "reintroduction" as a game bird 50 years ago. This is not uncommon, and is the hallmark product of the hands of human interference: "....When a species is introduced into a new and favorable habitat, its numbers increase phenomenally at first, and then level off at a population far under theoretical possibilities...." (Welty and Batista, The Life of Birds, 1990) The higher the social organization of the species, as exhibited by Canada geese with their intricate family relationships (comparable to human families) and social hierarchy (which begins just days after goslings are hatched in their rehearsing for future pecking-order battles), the more fierce the competition becomes for nesting sites, pair formation, and social ranking as the population increases. In nature, there is no free lunch forever, as Darwin had recognized: "...the struggle [for existence] will be most severe between the individuals of the same species...." (C. Darwin, The Origin of Species, 1859) Were this not the case, we would need 100 billion earths to support all the species that ever existed on the planet.
University of Vermont Professor Emeritus and naturalist, Hernd Heinrich, studied a family of Canada geese for 6 years nesting in a beaver pond near his home in Vermont. He recorded the daily, almost incessant rivalry, fighting and sometimes fatality which occurred among individual geese. At the end of his diary he concludes: "If my little exercise in geese-watching has taught me one thing, it is that geese would eventually manage their own population as a result of their intense competition and their mutual destruction of eggs and young at breeding sites. Hunting pressure would, in general, have little effect on the population, because it would simply relax the competition and strife that would otherwise limit reproduction...." (The Geese Of Beaver Bog, 2004) If nature is left to itself, the geese will harass and haze themselves, and disrupt and destroy their own eggs and nests--limiting breeding potential. No one has studied the Canada geese in their lifetime more than the late Dr. Harold Hanson, research biologist with the Illinois Natural History Survey (1943-1992) and discoverer in 1962 of the once-thought extinct giant Canada goose (Branta canadensis maxima). After more than 30 years of field research of Canada geese populations throughout the United States and parts of Canada, he states "....The carrying capacity of an area is determined to a large degree by the number of attractive nesting niches available, but if these are already occupied by breeding pairs, then territorial conflict becomes the dominant factor in regulating the population.... Research in recent years has increasingly revealed the degree to which populations of many animals are self-regulatory. The present state of knowledge on Canada geese supports this concept; final limitation of numbers in this species appears to reside in internal controls ...." (The Giant Canada Goose, 1997).
Thus, the observations and studies of two different scientists from two different eras concur as to the decisive limiting factor of the Canada geese (Branta canadensis)--in direct contrast to government-paid biologists on temporary projects who produce monographs to conform to political expediency and cost-effectiveness. It's time we give back to this member of the animal community the chance to live out the full meaning of its biological definition, and not the definitions imposed by the capriciousness of human society because of our failure to check our own population density. Nobody can manage the Canada geese better than the Canada geese.