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Conditioning of Sandhill Cranes During Fall Migration

Gary L. Krapu and Douglas H. Johnson

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Abstract: Body mass of adult female and male sandhill cranes (Grus canadensis) increased an average of 17 and 20%, respectively, from early September to late October on staging areas in central North Dakota and varied by year. Increases in body mass averaged 550 and 681 g among female and male G. c. canadensis, respectively, and 616 and 836 g among female and male G. c. rowani. Adult and juvenile G. c. rowani were lean at arrival, averaging 177 and 83 g of fat, respectively, and fat reserves increased to 677 and 482 g by mid-October. Fat-free dry mass increased by 12% among juveniles, reflecting substantial growth, but remained constant among adults. The importance of fall staging areas as conditioning sites for sandhill cranes, annual variation in body mass, and vulnerability of cranes to habitat loss underscore the need to monitor status of fall staging habitat in the northern plains region and to take steps to maintain suitable habitat where necessary.

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This resource is based on the following source (Northern Prairie Publication 0757):

Krapu, Gary L., and Douglas H. Johnson.  1990.  Conditioning of sandhill cranes 
     during fall migration.  Journal of Wildlife Management 54(2):234-238.

This resource should be cited as:

Krapu, Gary L., and Douglas H. Johnson.  1990.  Conditioning of sandhill cranes 
     during fall migration.  Journal of Wildlife Management 54(2):234-238.  
     Jamestown, ND: Northern Prairie Wildlife Research Center Online.  
     http://www.npwrc.usgs.gov/resource/birds/crancond/index.htm
     (Version 25JUL2002).

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Table of Contents

• Introduction
• Methods
• Results
• Discussion
• Literature Cited

Figures

• Figure 1 -- Body mass curves of adult male and female sandhill cranes by 10-day intervals during fall in central North Dakota.
• Figure 2 -- Population marginal means of body mass of sandhill cranes in central North Dakota, 1970-87.
• Figure 3 -- Body composition of juvenile and adult sandhill cranes collected during early fall and late fall in central North Dakota.

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Gary L. Krapu and Douglas H. Johnson, U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, P.O. Box 2096, Jamestown, ND 58402* (*Current address: U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th Street Southeast, Jamestown, ND 58401)

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