H. Bobby Fokidis,1, 2 Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA, and Savannah River Ecology Laboratory, Aiken, SC, 29802, USA
Christy Robertson, Department of Biological Sciences, Arkansas State University, State University, AR 72467, USA
Thomas
S. Risch, Department of Biological Sciences, Arkansas State University,
State University, AR 72467, USA and Savannah River Ecology Laboratory,
Aiken, SC 29802, USA
Abstract
We use survival analysis to compare failure of passive integrated transponder
(PIT) tags and loss of metal ear tags in 2,277 southern flying squirrels
(Glaucomys volans), 124 house mice (Mus musculus), 112 hispid
cotton rats (Sigmodon hispidus), and 374 deer (Peromyscus maniculatus)
and cotton mice (P. gossypinus). With the exception of cotton rats,
failure rates between ear and PIT tags differed by species. Flying squirrels
exhibited the highest proportional loss of both tag types and lost ear
tags more readily than PIT tags failed. The opposite was true for cotton
rats and deer and cotton mice. Most PIT tags appeared to fail shortly
after implantation (less than or equal to 3 days), except for flying squirrels
and, to a lesser extent, cotton rats. Ear tags exhibited a consistent
rate of loss in flying squirrels. Body mass did not influence failure
of PIT tags; however, flying squirrel body mass was associated with increased
loss of ear tags. For flying squirrels PIT tag failure increased with
the number of times an individual had already received a PIT tag that
failed. We provide recommendations for using PIT and ear tags in marking
rodents based on species-specific patterns and suggest the combined use
of external and internal markers to obtain the most reliable estimates
of population parameters.
Keywords: cotton mice, deer mice, ear tag, flying squirrels, Glaucomys
volans, hispid cotton rats, house mice, Mus musculus, passive
integrated transponder tags, Peromyscus gossypinus, P. maniculatus,
Sigmodon hispidus, survival analysis, tag failure
1
Email: Bobby. Fokidis@asu.edu
2 Present address: Arizona Sate University, School of Life
Sciences, Tempe, AZ 85257, USA
SREL
Reprint #2989
Fokidis, H. B., C. Robertson, and T. S. Risch. 2006. Keeping Tabs: Are Redundant Marking Systems Needed for Rodents? Wildlife Society Bulletin 34(3):764-771.
