(We will be continually updating this file. We urge you to return to it occasionally for additional information.)
Introduction
The authors of this web site, Bill Whan and Gerry Rising, yield to no one in our admiration for trumpeter swans, uniquely beautiful and imposing members of our North American avifauna. We mourn their passing in so many parts of their former range, and we support their restoration within that range where that can be accomplished without endangering other species. We also honor the biologists, wildlife managers, and other advocates who have undertaken the responsible fostering of restored swan populations in that region of Central and Western North America.
All the same, the trumpeter swan has never deserved -- nor has it received -- a designation as an endangered, or even a threatened, bird in North America. It is true that its Lower 48 populations numbered in the dozens fifty years ago, but it was never numerous south of Canada, and healthy populations in the thousands have for centuries persisted in western Canada and Alaska.
Our admiration and advocacy for these beautiful creatures does not extend, however, to some of the excesses of certain swan enthusiasts. They have chosen to assert, on the basis of unsatisfactory evidence, that trumpeters once bred and wintered far and wide across eastern North America. They have persuaded some state and provincial wildlife agencies to undertake expensive and demonstrably unsuccessful "restorations" of trumpeter swans in areas where they have no claim to native status. They have influenced a few scholars to undertake radical re-drawings of the species' range map, to produce a range far in excess of that accepted by generations of scholars. They have attempted to manipulate the public's esteem and sympathy for this charismatic species to justify its introduction into habitats where it has no place, and where it may in fact constitute a threat to the native ecosystem.
We oppose this re-conceptualization of the trumpeter swan's range, both on behalf of the swans themselves and on behalf of other species in the habitats into which they might be introduced.
It turns out that the issue we raise about the trumpeter swan's historical range is an important one. The orthographic difference between introductions and reintroductions may only be two letters, but the conceptual difference is great. You need only read the differing concerns raised in the International Union for the Conservation of Nature and Natural Resources Position Statement on Translocation of Living Organisms to see how important is this consideration. (At this site compare the requirements for re-stocking and re-introductions with those for introductions.) Clearly the requirements for reestablishing the population of an extirpated species are far less than those for introducing an alien species new to a region.
We have argued our concerns about introductions in Eastern North America with a director of the Trumpeter Swan Society as a "point/counterpoint" debate in the pages of Birding magazine. To see both sides of this important issue follow this link. Our position is described in greater detail in the following sections.
Trumpeter Swans Did NOT Breed in Eastern North America
It should be recognized at the outset that in
justifying our claim that
trumpeter swans never bred in Eastern North America we face a logical
difficulty. It is obviously impossible to prove that an activity such as
breeding did not occur in a region. One friend has even suggested
that
the trumpeter swan might have bred in the east, as he puts it, "before
the Ice Age, their bones have been lost and therefore we cannot say that
this region is outside their breeding area." (Of course, the problem
inherent in that line of reasoning is that it would prevent our
delineating historical breeding ranges for any species. We might then
claim justification for the re-introduction of ostriches to New England.)
What we seek to establish then is something less than logical proof, but
something that we believe should be acceptable to those who examine the
evidence we are gathering. We propose to show that acceptable evidence for
this swan species breeding in Eastern North America does not exist and
that, rather, the available evidence points to their not breeding here.
Specifically, we have set out to establish that Trumpeter Swans did not breed in Eastern North America, that is in Ohio, Pennsylvania, New York, the New England States and states to the south of them nor in southeastern Ontario, Quebec (except near the shores of James and Hudson Bays) and the Maritime Provinces. By southeastern Ontario we mean the part of that province to the east and south of Georgian Bay. This is the region of Canada and United States east of the gray-stippled breeding range shown on this first map.
A major concern for everyone interested in this problem is the fact that those with whom we differ have managed to redefine the range according to their own interests. Consider in this regard two maps of North America displaying the range of trumpeter swans. The first is taken from Frank C. Bellrose, Ducks, Geese and Swans of North America (Harrisburg, PA: Stackpole Books, 1976) p. 89. Although derived independently, it virtually coincides with the map based on information summarized by Ralph S. Palmer and Winston E. Banko on page 61 of Palmer's Handbook of North American Birds, Volume 2 (New Haven, CT: Yale University Press, 1976).
The second map owes its provenance to a paper
originally prepared in
1978 by Philip M. Rogers and Donald A. Hammer entitled "Ancestral Breeding
and Wintering Ranges of the Trumpeter Swan (Cygnus buccinator) in the
Eastern United States." After many years circulating in typescript, it was
finally printed in North American Swans: Bulletin of The Trumpeter Swan
Society 27: 1 (December 1998): pages 13-29. The maps in this paper
that
form the basis of this extreme range extension appear on pages 23 and 24.
(On it the hypothetical trumpeter swan breeding range is the region
between the heavy dashed lines.)
The difference between these two maps should be evident to anyone examining them. Unfortunately now all those who wish to establish a trumpeter swan population in the East base their ideas on this map and others like it. For example, a map similar to this has been displayed on the Trumpeter Swan Society website.
Of even greater significance is the fact that widely recognized documents accept this range extension. The best example of this is Carl D. Mitchell's 1994 Life History No. 105 "Trumpeter Swan" in Birds of North America (Philadelphia, PA: The Academy of Natural Sciences of Philadelphia). Mr. Mitchell is a former board member of the Trumpeter Swan Society. He extends the trumpeter's historical breeding range to "Ontario, Quebec, east to Nova Scotia, New Brunswick, and Newfoundland" citing publications by Lumsden (another society board member) and Alison, despite the latter's direct contradiction. In the paper Mitchell cites Alison states: "There is no material evidence that trumpeters have bred anywhere in Ontario."
We believe that this vast range extension encompassing hundreds of thousands of square miles is unwarranted. Still we would be little concerned if this were the historical range of, say, the pine siskin. The effect of such an error would be negligible. But the trumpeter swan is one of our largest North American birds and the impact of this alien species on our already severely reduced eastern marshes would, as we have pointed out in our paper in Birding magazine, be very serious. It is for that reason that we are carrying out this research.
We are then addressing this issue in two ways:
Those Who Oppose Us Face Their Own Problems
While we organize the great volume of literature we have surveyed, we feel that it is important to point out that those arguing for trumpeter swans having bred in Eastern North America face serious problems themselves:
Based on what we have found so far and the scientific principle of parsimony, we remain convinced that the trumpeter swan's historical breeding range did not extended east of Michigan, western Ontario and the eastern shores of Hudson's and James Bay.
Some Earlier Papers and Our Working Bibliography
For additional background information, you may wish to read our earlier papers on swan distribution and introduction or examine our bibliography which we are attempting to keep reasonably up-to-date:
We plan to add information to this site as it is gathered and developed. Meanwhile we invite readers to provide information or to offer their own responses to this controversy.-- Gerry Rising