Northern Prairie Wildlife Research Center
Communal Roosting and Foraging Behavior of Staging Sandhill Cranes
Donald W. Sparling and Gary L. Krapu
Abstract: Each spring more than 300,000 Sandhill Cranes (Grus
canadensis) roost communally at night in river channels in the Platte
River Valley of Nebraska and disperse at dawn to forage in agricultural fields.
Cranes with central roosts had activity ranges double the size of those with
peripheral roosts; 42% of the birds changed activity ranges prior to the onset
of migration. Minimum daily flight distance generally increased during the
staging period. Cranes used native grassland and planted hayland more often
than expected, relative to their percentage of occurrence, and fed longest
there; cornfields were under-utilized. These differences probably reflect,
in part, (1) limited distribution of grasslands and haylands resulting in
a greater energy expenditure to acquire protein in the form of macroinvertebrates
and (2) wider distribution of cornfields with adequate energy-rich foods but
limited protein. Cranes probably forage more efficiently and conserve energy
by following conspecifics from communal roosts to local feeding grounds, by
settling in fields where foraging flocks are already present, and by establishing
diurnal activity centers. Alert behavior varied with flock size but not as
predicted from group size, presumably because predation of staging adult cranes
is inconsequential.
This resource is based on the following source (Northern Prairie Publication
0895):
Sparling, Donald W., and Gary L. Krapu. 1994. Communal Roosting and Foraging
Behavior of Staging Sandhill Cranes. Wilson Bulletin 106(1):62-77.
This resource should be cited as:
Sparling, Donald W., and Gary L. Krapu. 1994. Communal Roosting and Foraging
Behavior of Staging Sandhill Cranes. Wilson Bulletin 106(1):62-77.
Jamestown, ND: Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.gov/resource/birds/comroost/index.htm
(Version 03JUN2002).
Table of Contents
- Introduction
- Study Area and Methods
- Radiotelemetry
- Time budgets
- Statistical analyses
- Results
- Characteristics and use of activity ranges
- Information sharing and associations among roosting cranes
- Habitat preference
- Group size and activities
- Discussion
- Spatial relationships
- Foraging as a factor of crane staging
- Influence of predation and behavior on group size
- Other influences
- Conservation concerns
- Acknowledgments
- Literature Cited
Tables and Figures
- Table 1 -- Number, type, and size
of activity ranges of Sandhill Cranes during Staging at the Platte River,
Nebraska.
- Table 2 -- Proportion of Sandhill
Crane visits and mean flight distances to different habitats during staging
in Nebraska.
- Table 3 -- Diurnal activity budgets
of staging Sandhill Cranes by type of habitat along the Platte River,
Nebraska.
- Table 4 -- Diurnal activity budgets
for Sandhill Cranes staging along the Platte River, Nebraska, by flock
size.
- Figure 1 -- Examples of activity ranges
and habitat locations for staging Sandhill Cranes.
- Figure 2 -- Minimum daily flight distance
through the Sandhill Crane staging periods.
- Figure 3 -- Observed frequencies for
departure intervals of Sandhill Cranes leaving roost sites compared to
expected based on a Poisson distribution of observed values.
Gary L. Krapu, U.S. Fish and Wildlife Service, Northern Prairie
Wildlife Research Center, P.O. Box 2096, Jamestown, North Dakota 58402.
Donald W. Sparling, U.S. Fish and Wildlife Service, Patuxent
Wildlife Research Center, 11510 American Holly Dr., Laurel, Maryland 20708.
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