Gordon Goldsborough

Effects of Water Depth, Cover and Food Resources on Habitat use of Marsh Birds and Waterfowl in Boreal Wetlands of Manitoba, Canada

Abstract. To evaluate water-level manipulations as a management tool in boreal wetlands, marsh bird and waterfowl habitat use were studied in the Saskatchewan River Delta, Manitoba, Canada, during 2008 and 2009. Call-response and aerial surveys were used to estimate densities of marsh birds and waterfowl, respectively, within six wetland basins undergoing two different water-level treatments. Generalized linear models were used to determine relationships between presence and densities of birds to water depth, vegetation characteristics, and relative forage fish and invertebrate abundances at two spatial scales. American Bittern (Botaurus lentiginosus) and Piedbilled Grebe (Podilymbus podiceps) densities were positively influenced by water depth and relative fish abundance. American Coots (Fulica americana) and diver waterfowl (Aythya, Bucephala) also responded positively to increased water depth, whereas dabbler waterfowl (Anas, Aix) were negatively influenced by increasing water depth. Densities of Sora (Porzana Carolina) and Virginia Rail (Rallus limicola) were positively correlated with the relative abundances of invertebrates, but negatively correlated with relative fish abundance. Due to the high avian biodiversity in the region, managers should focus on providing a variety of wetland habitats. Using a combination of partial water-level drawdowns and high water, habitat for numerous avian species can be created simultaneously within wetland complexes.

Requiem for a field station: the loss of a Canadian ornithological treasure

Nestled on the southern shore of Lake Manitoba about 100 km northwest of Winnipeg (Fig. 1, 2), the University of Manitoba’s Delta Marsh Field Station (DMFS) had withstood many tribulations since its creation by Dr. Jennifer M. Shay OC in 1966. Many a financial and natural storm had done battle with its relatively small group of academics, staff, students, and friends who created it and supported a vision worthy of its potential over the years. And so, to some degree, when the flood waters lapped at its foundation in the spring and summer of 2011, many of us believed it would similarly endure and emerge once again as it always had. After all, it had apparently only just made it through its greatest battle ever with University of Manitoba administrators who had launched a major effort to close its doors. That initiative was justified by a corporate “bottom-line” argument but was also motivated by ignorance of both the role this station has played in the education of field biologists and ornithologists in general in Canada, its environmental and conservation significance, and of its future potential. Alas, the massive floodwaters brought to its doorstep by the man-made Assiniboine River Diversion proved to be a final justification to bulldoze it to the ground and to end a final chapter in what was an ornithological jewel of national and international significance. Instead of repairing and rebuilding this facility in tribute to its long service and to plan a safer future, it became one more casualty of fiscal restraint and deficit reduction, a victim of an uncaring and disinterested community. The Mission Statement of this field station was “to foster excellence in research and teaching, extend University resources into the community, and promote sound and sensitive environmental stewardship practices.” At precisely the time when such values are needed most, we have instead witnessed a draconian and opportunistic end to a proud 44-year record. We cannot do justice here to the many contributions made to Canadian ornithology by researchers working out of this station. Instead, and for the record, we list the ornithologically related theses and publications that were generated here (Appendix 1, 2) and reflect on other contributions including the 18-year history of the Delta Marsh Bird Observatory that was hosted at the DMFS. This list is a minimum since there are currently papers in review which we have not included here. We acknowledge also the contributions to other, nonornithological research and teaching and reflect more broadly on the status and fate of similar facilities elsewhere in Canada and North America.