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A FEDERAL COURT DECISION AND MUTE SWANS IN CONNECTICUT
Steve Oresman January 18, 2002

Recent media articles on Mute Swans (Cygnus olor) with headlines such as"Federal Law Speaks for Mute Swans" and "Protection of Mute Swans Ordered By Federal Court" may create the impression that there are new research findings on the status of Mute Swans or that new protections have been ordered. This
is not the case. The court ruled only that the Mute Swan was covered under the Migratory Bird Treat Act, not that it was a native species or migratory in the usual sense of that word.

COA is not an advocacy organization, but part of its mission is to"disseminate accurate scientific information about birds and their habit." The discussion below is intended to support that objective.

The Federal Court of Appeals in the District of Columbia ruled in interpreting the legal language of four different migratory bird treaties, and also on legal governmental administrative procedural grounds, that the Mute Swan was covered under the Migratory Bird Treaty Act. While the COA is not qualified to comment on the legal reasoning, it is important to note that the court also said, "Furthermore, including the Mute Swan on the list of migratory birds does not prevent the Secretary from controlling any potential
harmful effects caused by Mute Swans."

The status of Mute Swans in the U.S. is clear in both historical and in current ornithological literature. The Mute Swan is an introduced Eurasian species. It is not mentioned by either Alexander Wilson or by John James Audubon, the leading figures in early American ornithology. It is further not listed as occurring in the eastern U.S. in Chapman "Birds of Eastern North America" 1895, "Birds of America" edited by Pearson with an extensive and distinguished board of advisors 1917, and Forbush "Birds of Massachusetts and
other New England States" 1925. Then how and when did the Mute Swan become established here?

The consensus is that it was introduced first on Long Island and in the lower Hudson Valley between 1910 and 1912. Feral birds were reported in Connecticut by the 1930s but breeding was not established here until the late 1950s (Bevier, Editor, The Atlas of Breeding Birds of Connecticut 1994). The American Ornithologists Union check list 1998 edition says, "Introduced and established in North America." In addition this introduced status is not questioned in any of the principal regional bird literature and is further
supported by an examination of all the major field guides from the original Peterson to the current Sibley. Thus the conclusion that the Mute Swan was introduced from Europe, where it is currently "Long semi-domesticated and mainly resident" (Peterson et.al. "Birds of Britain and Europe 1993).

As far as migration there is again agreement that Mute Swans movements are from inland waters to open and coastal waters when their resident habitat freezes. The Federal Court relied in part on testimony that in this type of movement some swans may move across the Canadian border. This limited movement was one of the legal arguments supporting its coverage under the Act.

Since Mute Swans have reached Connecticut, their numbers have exploded. The Christmas Bird Count data show that their population has increased from virtually none in the early 50’s to about 1200 in 2000. The impact of this growth and of possible future growth on the environment is not clear. However the US Fish and Wildlife Service is clearly concerned, and proposed control activities in Maryland, which were the cause of the lawsuit. The Court quoted the acting Director of USFWS "If uncontrolled, Mute Swans pose a serious
threat to the ecological integrity of many areas, including the National Wildlife Refuge System and other Federal lands committed to the maintenance of natural wildlife diversity."

The impact of swan populations in Connecticut is not clear and more research needs to be done. There have been a number of studies which while citing aggressive behavior of swans so show no measurable impact on other waterfowl. This research, however, appears to be limited to small inland studies covering a few pairs or to the short term effects of larger concentrations of swans on vegetation. Since Mute Swan populations and control are clearly subjects of some controversy in Connecticut, it would seem desirable for the State DEP or the McKinney Refuge of the USFWS to conduct or fund some long term controlled studies on the ecological impact of Mute Swans in areas where there are dense populations. It would also be useful as a first step for the DEP or McKinney to fund an independent academic review and summary of all the available research on this subject both published and unpublished in the U.S. and Europe.