Conclusions
Use of the Shannon Index of diversity and evenness allowed
interpretation of feeding trial data for two potentially competing
chipmunk species. The versatility of diversity indices allows for
simultaneous assessments of cafeteria-trial data that is not restricted
by the number of different choices offered. In addition, behavioral
titrations can be conducted to assess the effects of varying frequency
of specific food items on foraging preferences. Finally, this approach
is not reliant on consumption curves and does not suffer from some of
the statistical shortcomings of conducting all possible pairwise
comparisons.
This approach yielded insights into resource utilization in the small
mammal community. Food choices by foraging chipmunks reflect body size,
with the smaller N . minimus consuming small-seededA. rubrum whereas larger T . striatus preferred tree
species with the largest seeds (A. saccharum and C.
cornuta ). This is consistent with studies of rodent granivores in other
systems. An unexpected result concerned individualistic foraging
preference: individual T . striatus preferred eitherA. saccharum or C. cornuta , but not both. This implies
variation in individual response to foraging options and merits further
attention.
Acknowledgments .
The authors would like to thank Ashleigh O’Reilly, Camille A. Berrocal,
Maggie Wisniewska, Luke DeGroote, Riley Parrot, and Cayla Bendel for
assistance in the field. The collection of data was completed during the
Practicum for Field Environmental Biology course at the University of
Notre Dame Environmental Research Center and was also an undergraduate
thesis for AL in the Glynn Family Honors Program at the University of
Notre Dame. All use of wild animals was approved by the Institutional
Animal Care and Use Committee at the University of Notre Dame (protocol
#14-047) and by the Department of Natural Resources for both Wisconsin
(SRL-NOR- 026-0409) and Michigan (SC 1168). Funding was provided by the
Bernard J. Hank Family Endowment to the University of Notre Dame. None
of the authors have any conflicts of interest to declare.