PROCEEDINGS OF THE NORTH AMERICAN CRANE WORKSHOP

Title:
SANDHILL CRANE NEST HABITAT SELECTION AND FACTORS AFFECTING NEST SUCCESS IN NORTHWESTERN MINNESOTA

Date: 2008

Authors:
STEPHEN J. MAXSON, Minnesota Department of Natural Resources
JOHN R. FIEBERG, Minnesota Department of Natural Resources
MICHAEL R. RIGGS, Minnesota Department of Natural Resources

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Citation:
Maxson, S. J., J. R. Fieberg, and M. R. Riggs. 2008. Sandhill crane nest habitat selection and factors affecting nest success in northwestern Minnesota. Proceedings of the North American Crane Workshop 10:90-97.

Abstract:
We studied 62 greater sandhill crane (Grus canadensis tabida) nests in northwestern Minnesota during 1989-1991 to document nest habitat use and selection, nest success, and factors associated with nest success. We recorded 15 habitat variables at each nest and at a randomly selected site in the same wetland. Nests were in basins 0.01-601 ha (median = 2.2 ha) and at water depths 0-35.7 cm (median = 9.7 cm). Cattail (Typha sp.) was the dominant vegetation at 58.0% of nests while 21.0% were at sites dominated by phragmites (Phragmites australis). Conditional logistic regression models indicated that locations with lower concealment indices, lower log sedge (Carex sp.) stem counts, and higher log phragmites stem counts were more likely to be associated with nest sites. Estimated nest success was 56% (apparent), 40% (Mayfield), and 47% (logistic-exposure model). Most nest failures appeared due to mammalian predation. Nest depredation appeared to increase as nest initiation dates became later, but after accounting for differences in exposure times, this difference was no longer evident. Year had the strongest effect on nest success with the lowest success recorded in 1990, a dry spring. Logistic exposure models suggested that nest success tended to increase with increasing water depth at the nest site or as concealment indices decreased.

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