Date of Award
Doctor of Philosophy (PhD)
Teeming with macroinvertebrates, hundreds of tiny wetlands dotting the prairie region of North Dakota provide nutrient rich foraging sites for large numbers of migratory shorebirds. Because these wetlands are typically small, dispersed and ephemeral, documentation of shorebird numbers in the region has been a difficult task. Large variation in survey data has resulted in an overall underestimate in the value of this shorebird habitat.
To assess the status of local migratory shorebirds, I conducted weekly shorebird surveys at eight sites within Kelly's Slough National Wildlife Refuge. These surveys included a bi-weekly inventory of resident invertebrates, a well established prey base for shorebirds. Surveys and inventories were completed from 1 April through 30 September of 2000, 2001 and 2002. Additionally, I conducted two years of management techniques on a selected site, documenting shorebird and invertebrate response to water level manipulations. Using information about the local shorebird population and documented responses to management, I outlined a flooding and drawdown regime that maximized optimal shorebird foraging habitat at the site.
Considerable variation was present in the shorebird population both within and among years. Most shorebirds were long or intermediate distance migrants and were present the last two weeks in May and from mid-July to the beginning of August. The number of shorebirds during fall migration, the last two weeks in July, was nearly three times the number of spring migrants. Despite monthly and yearly variation, the total number of shorebirds surpassed 26,000 birds for each year of the study.
A comparison of invertebrate and shorebird numbers shows a significant negative relationship. At the managed site and other sites, invertebrate numbers have less seasonal variation than shorebird numbers, and show a marked decline in July and August when shorebird numbers peak. Preliminary management actions were successful in creating and maintaining shorebird habitat throughout the season.
The results of this project solidify the importance of this refuge to migratory shorebirds. Suitable shorebird habitat must be maintained from mid-April through mid- September to accommodate the temporal variation that exists in northbound and southbound migrants. Continued shorebird management at the refuge helps with worldwide efforts to conserve migratory shorebirds.
Carey, Corinne A., "Status of Migratory Shorebirds at an Inland Stopover Site in the Northern Plains Prairie Pothole Region" (2003). Theses and Dissertations. 3218.