Dear Dr. Frisch:

The following comments are provided in response to your request for a review of the State of Wisconsin Department of Natural Resources' April 2000 GUIDELINES FOR CONTAMINANTS SCREENING OF HARVESTED URBAN GEESE and its May 9, 2000, GUIDELINES FOR HEALTH SCREENING OF URBAN GOOSE GOSLING RELOCATION.

GUIDELINES FOR CONTAMINANTS SCREENING

According to the Guidelines, "sampling should be done 1 year in advance of the proposed harvest" and "[i]f the population targeted for control has been sampled previously, and there are no environmental or management changes that would alter the birds' exposure to toxins, no further sampling is required."

The obvious flaw in these guidelines is the unsubstantiated assumption that the targeted populations utilize the same habitats year after year and that the Department knows what those habitats are, where they are located and what contaminants are present, and it assumes that no geese from other areas with different contaminant exposures move in to occupy vacancies created in those habitats by the Department's urban Canada goose control program.

The fact is, "resident" Canada geese commonly travel long distances from their nesting areas, especially in their molt migrations. For example, Nelson and Oetting (1991) reported that Canada geese from Wisconsin have been found in Kansas; Canada geese from Michigan have been found in Indiana, Ohio Illinois, Kentucky, Tennessee, Wisconsin, Alabama, the Carolinas and on Akamiska Island in James Bay; Canada geese from Iowa have been found in Minnesota and Missouri; Canada geese from Missouri have been found in South Dakota, Wisconsin and Ontario; Canada geese from Illinois have been found in Wisconsin, Michigan, Ontario, Minnesota, North Dakota, Manitoba, Kentucky and Tennessee; and Canada geese from Ohio have been found in Michigan, Ontario, Akamiska Island and on the Thelon River in the Northwest Territories.

As Nelson and Oetting (1991) point out, "we really have little knowledge about the population ecology and adaptive characteristics of the many Canada geese that grace our cities and suburbs" and their "population dynamics, and association with other goose populations. . . are poorly understood." The Department's Guidelines, however, are based on the erroneous premise that urban Canada geese occur only in static populations that consistently utilize rigidly defined local habitats with known contaminant loads so that their exposure to toxicants can be accurately determined by sampling at one point in time.

GUIDELINES FOR HEALTH TESTING

According to the Guidelines, "These [urban] geese may harbor contagious bacteria, viruses, or parasites that can have a negative impact on resident waterfowl populations present on the translocation sites." Therefore, "The Wildlife Health Team. . . will collect biological health samples form 10%. . . of the total number of goslings translocated." "Biological health samples include whole blood and cloacal swabs from individual live goslings, and fecal samples collected from the general population of geese present at the original capture site." The biological sample assays listed in the Guidelines include cloacal swabs for "general enteric and Salmonella bacterial cultures," serology for mycoplasma, Newcastle disease, avian influenza virus and chlamydia, and fecal parasite examination. "Wildlife Health will delay or deny gosling translocation efforts if it is determined a contagious disease is present in the original goose flock which will have severe health impacts on waterfowl in recipient wetlands."

Unfortunately, the Department's Guidelines for Health Testing of Urban Goose Gosling Relocation suffer from two fundamental deficiencies which render the proposed testing clearly perfunctory and virtually worthless. Not only are all of the listed "contagious diseases" for which the urban geese are to be tested already are present in migratory waterfowl populations, but none of them causes "severe health impacts" in migratory waterfowl populations.

"General enteric bacteria" occur normally in all waterfowl and other vertebrates and invertebrates and they are of no epizootiologic significance.

Salmonellae have been isolated from many species of wild waterfowl, but reports of disease are uncommon and usually involve single birds (Wobeser, 1997)

Samuel et al. (1996) reported from 25% to >80% prevalence of antibody to Mycoplasma anatis in adult breeding mallards and wintering mallards and black ducks sampled in the eastern and central United States from 1988 to 1992, and they reported a 50% prevalence of antibody in juvenile mallards and black ducks up to 8 months of age, indicating a high transmission rate among wild waterfowl. However, the pathogenicity of various mycoplasmas for waterfowl is uncertain (Wobeser, 1997).

Newcastle disease virus has been isolated from Canada geese, green-winged teal, blue-winged teal, cinnamon teal, mallards, lesser scaup, gadwall, black ducks, wood ducks, pintails and American wigeon, and antibody to the virus has been found in many wild waterfowl, indicating that a significant proportion of migratory waterfowl regularly become infected with Newcastle disease virus (Wobeser, 1997). However, Newcastle disease viruses isolated from migratory waterfowl have been of low pathogenicity (Wobeser, 1997).

Avian influenza viruses are widespread in migratory waterfowl, which are considered to be the natural reservoir if influenza viruses, but, "There are no reports of clinical disease due to influenza in wild waterfowl" (Wobeser, 1997).

Chalamydia infections have been reported in 114 species of free-living wild birds, but "[t]here is little evidence that chlamydiae are important as a cause of clinical disease in wild waterfowl" (Wobeser, 1997).

Virtually all wild waterfowl are exposed to and infected with a variety of endoparasites. In fact, "Parasitism is such a common phenomenon that it is considered to be almost normal" (Wobeser, 1997). In fact, "A plethora of metazoa have been described from wild waterfowl. . ." but "The significance and actual effects of most of these are unclear. . ." (Wobeser, 1997). Because "the difference between 'normal' and 'abnormal' parasitism is quantitative rather than qualitative. . .one must be familiar with what constitutes the 'usual' parasite load in apparently healthy birds in an area" (Wobeser, 1997). As Friend and Franson (1999) point out:

"The presence of parasites in birds and other animals is the rule, rather than the exception. Hundreds of parasite species have been identified from free-ranging wild birds; however, the presence of parasites does not necessarily equate with disease. Most parasites identified from wild birds cause no clinical disease."

Therefore, the demonstration of evidence of parasites in fecal samples collected randomly from environments occupied by urban Canada geese in the absence of clinical disease resulting from parasitism is of virtually no epizootiologic significance or value.

Avian cholera is generally regarded to be the most significant contagious disease affecting migratory waterfowl (Friend and Franson, 1999; Wobeser, 1997), and duck plague frequently is cited by wildlife agencies as posing a major threat to migratory waterfowl populations (Friend and Franson, 1999), but the Guidelines do not propose testing for either of these diseases. It is instructive to note in this context that waterfowl infected with either of these diseases cannot reliably be detected with serologic techniques, and identification requires more involved procedures to isolate the causative agents. This is of little significance in the Department's health testing program for urban Canada geese, however, because both avian cholera and duck plague already are enzootic in migratory waterfowl populations (Beard et al., 1984: Botzler, 1991; Pearson and Cassidy, 1997; Wobeser, 1997).

A major conceptual fallacy of the Department's proposed health testing program for urban Canada geese scheduled for translocation to prevent the introduction of contagious diseases "which will have severe health impacts on waterfowl in recipient wetlands" is that it fails to include any provisions for determining the prevalence of those diseases in the waterfowl already present on those recipient wetlands. Even if urban Canada geese scheduled for translocation were infected with contagious diseases with the potential to "have severe health impacts on waterfowl in recipient wetlands," it would be of little consequence if those diseases already are present in the waterfowl on the recipient wetlands.

Conclusions

The Wisconsin Department of Natural Resources' April 2000 Guidelines for Contaminants Screening of Harvested Urban Geese will not provide reliable information on the types and levels of contaminants in urban Canada geese processed into human food products for donation to food pantries and, therefore, will not permit an objective evaluation of whether the contaminant levels meet safe human consumption levels.

The Wisconsin Department of Natural Resources' May 9, 2000, Guidelines for Health Testing of Urban Goose Gosling Relocation are based on a test menu selected for technical ease and convenience rather than epizootiologic significance. All of the diseases listed on the test menu already are enzootic in migratory waterfowl populations and none of them poses a threat for "severe health impacts on waterfowl in recipient wetlands." Because the proposed health testing program considers only contagious diseases in urban Canada geese scheduled for translocation but not in the waterfowl on the recipient wetlands, and because all of the diseases listed already are present in migratory waterfowl where they do not cause significant disease problems, the proposed health testing program will provide no useful or relevant information.

Because the contaminants screening proposed in the Department's April, 2000, guidelines will not provide reliable information on the types and levels of toxicants in urban Canada geese processed for human consumption, and because the health testing proposed in the Department's May 9, 2000, guidelines will not provide useful or relevant information on contagious diseases in urban Canada scheduled for translocation, the proposed testing is of little value, except perhaps to fabricate a deception that the Department is performing meaningful monitoring of health hazards posed by urban Canada geese to support its urban Canada goose control program.

Sincerely,

Gary L. Pearson, D.V.M.

Beard, C. W., G. W. Burger, J. R. Cain, F. E. Kellogg and L. Leibovitz. 1984. Duck plague (duck virus enteritis) panel report: A review of issues and information related to Fish and Wildlife Service policies and practices. U. F. Fish and Wildlife Service, Washington, D. C. 15 pp.

Botzler, R. G. 1991. Epizootiology of avian cholera in wildfowl. Journal of Wildlife Diseases 27: 367-395.

Friend, M. and J. C. Franson. 1999. Field Manual of Wildlife Diseases: General Field Procedures and Diseases of Birds. U. S. Department of the Interior, U. S. Geological Survey, Biological Resources Division, National Wildlife Health Center. Madison Wisconsin. Information and Technology Report 1999-001. 425 pp.

Nelson, H. K. and R. B. Oetting. 1991. Recent urbanization of Canada geese. International Canada Goose Symposium. Milwaukee, Wisconsin. 27 pp.

Pearson, G. L. and D. R. Cassidy. 1997. Perspectives on the diagnosis, epizootiology, and control of the 1973 duck plague epizootic in wild waterfowl at Lake Andes, South Dakota. Journal of Wildlife Diseases 33: 681-705.

Samuel, M. D., D. R. Golcberg, C. B. Thomas, P. Sharp, J. R. Robb, G. L. Krapu, B. N. Nersessian, K. P. Kenow, C. E. Korschgen, W. H. Chipley and M. J. Conroy. 1996. Journal of Wildlife Diseases 32: 331-337.

Wobeser, G. A. 1997. Diseases of Wild Waterfowl, 2nd Ed. Plenum Press, New York, New York. 324 pp.