Browsing by Subject "Department of Fisheries, Wildlife and Conservation Biology"

Now showing 1 - 4 of 4
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    Effectiveness of Vehicle-towed Nest Drags at Finding Duck Nests
    (2011-04-13) Nosal, Amanda
    Effective wildlife management depends on the assumption that the research techniques employed are scientifically and ecologically sound. In the management of popular waterfowl species, like dabbling ducks, nest density and success are often assessed using a vehicle-towed nest drag. This technique involves systematically searching a treeless, herbaceous habitat using two vehicles such as jeeps or ATVs with a heavy cable and chain, or just a chain, stretched between them. The nest drag passes over the vegetation where ducks nest, causing females to flush from the disturbance. Their nests can then be marked and revisited to collect data on nesting densities and reproductive success, and consequently used to devise appropriate management schemes. By analyzing data collected in habitats owned by Ducks Unlimited Canada, I evaluated the effectiveness of vehicle-towed nest drags at finding duck nests using the specialized population estimation software program DISTANCE. Specifically, I tested if nest detection was influenced by the distance from the towing vehicles, nest age, and duck species. My research provides “correction factors” that allow investigators to estimate the proportion of nests that are missed during regular surveys for waterfowl nests.
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    Effects of rotational grazing on grassland songbirds on U.S. Dairy farms.
    (2011-04) Clower, Kathryn Marie
    Dairy pastures and hayfields provide important habitat for several grassland bird species of conservation concern, and farm management can have a substantial impact on populations of these species. Understanding the value of rotational grazing to grassland birds may reveal new opportunities for bird conservation, and may clarify the degree to which this management practice can enhance agricultural sustainability. We evaluated management practices (e.g. grazing intensity) and habitat variables (e.g. land cover) at 100m and 1200m radii on 53 dairy farms in Wisconsin, Pennsylvania and New York, in order to assess whether rotational grazing farms supported substantially higher abundances of three grassland bird species – Savannah Sparrow, Bobolink, and Grasshopper Sparrow -- than other dairy farms. We conducted 2-way ANOVAs in SAS (9.2) to examine differences in relative abundance among states and farm types using PROC GENMOD. Additionally, we modeled relative abundance as a response to Julian date and land cover at 100m and 1200m radii using PROC GLIMMIX. Abundances of each grassland bird species did not differ significantly among farm types. Responses to land-cover variables differed among species but demonstrated that relative abundance was positively associated with the proportion of hayfields and pastures in the surrounding landscape, and negatively associated with woody cover. Savannah Sparrows and Grasshopper Sparrows each showed a significant response to at least one habitat variable at the 1200m scale. Our results suggest that differences in abundance of grassland birds among farm types are modest at best, and that the impact of management practices on these species must be understood in the context of the surrounding landscape. Our data show that grassland birds can benefit from increases in the total area of pasture and hayfields on the landscape, which could be provided through broad adoption of rotational grazing. However, the benefits provided by increasing grassland habitats on a small number of farms are unlikely to have a substantial impact on bird populations, particularly in the context of a highly fragmented agricultural landscape. Future research for conservation planning and policy development should focus on the landscape scale (i.e. ! 500 ha) to ensure that conservation actions are most effective.
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    Olfactory Discrimination of Amino Acid Mixtures in the Goldfish (Carassius auratus)
    (2010-10-05) Carlson, Andrew
    Research Questions: Can goldfish be trained to discriminate between amino acid odor mixtures? If so, to what level of specificity can they be trained? How complex can the amino acid mixtures be? How do goldfish discriminate between amino acids odor mixtures? Do they learn individual amino acids, or do they identify an odor by sensing the amino acids collectively?
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    Wild Turkeys: Radio Telemetry in the Twin Cities
    (2011-04-13) Nelson, Emilee
    Wild turkeys have made a dramatic comeback since they were extirpated from Minnesota in the late 1800’s from unregulated hunting practices, and were successfully reintroduced in 1970 to most regions of the state. As turkeys continue to expand their ranges into suburban areas, management techniques are becoming increasingly difficult due to close proximity to humans. Residents in cities surrounding Minneapolis are seeing an increase in turkey density year after year, and many homeowners are issuing complaints about property damage and nuisance activities exhibited by the large birds. Because the turkeys are within city limits, they can only be removed by professionals through expensive trapping methods. My project is currently analyzing urban home range and habitat use of wild turkeys by using radio telemetry on turkeys in Shoreview and Lake Elmo. By understanding how these turkeys are using fragmented urban habitats , managers can mitigate future tension between residents and turkeys, which not only represent a large value to biodiversity in Minnesota, but a large source of income to the state ($47 million annually).