Date of Award

9-15-2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Richard Crawford

Abstract

Habitat loss from human settlement and intensified farming has brought about a rapid loss of grassland and wetland habitats. Cultivated wild rice (Zizania palustris) paddies and associated uplands could help counteract this loss of habitat by providing nesting and feeding habitat for a variety of wildlife. Waterfowl have been the focus of many management activities designed to combat habitat loss. Although it is generally believed that the overall effects of waterfowl habitat management and enhancement are beneficial to other game and non-game birds, many direct effects have not been investigated. The objectives of this study were to examine the use of cultivated wild rice areas by upland nesting waterfowl and American bitterns (Botaurus lentiginosus) and to examine the effects of management activities on nest site selection and nest success of waterfowl and American bitterns. Waterfowl nest success reached levels necessary to maintain population stability, with Mayfield nest success averaging 20% over the five years. American bitterns were also successful at the site with Mayfield nest success averaging 54%. Nest predation was the main cause of nest failure although predator control measures did benefit nesting birds. Nest success of waterfowl and bitterns was not affected by initiation date or vegetation height at the nest. Land use at the site was divided into six general classes: idle field, conservation reserve program land (CRP), pasture, dense nesting cover (DNC) unmowed, DNC-mowed, and odd areas. American bitterns nested most often in tall vegetation with an average 100% visual obstruction reading (VOR) of 6.00 dm, while average VOR at waterfowl nests was 3.40 dm. American bitterns nested mainly in DNC unmowed (0.078 nests/ha) and idle fields (0.053 nests/ha). The highest densities of waterfowl nests were in DNC mowed (0.215 nests/ha) and DNC unmowed (0.200 nests/ha). Mayfield nest success was high in idle fields (57%, N = 38) for bitterns and waterfowl (25%, N = 84). Radio-marked American bitterns were systematically relocated from May through August, 2000–2001. Seasonal core areas and low use areas were determined for six males and six females. Male breeding home-ranges averaged 17 ha (N = 6) and female home-ranges averaged 29 ha ( N = 6).

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