Population Dynamics of Nine-Banded Armadillos: Insights from a Removal Experiment

Abstract

From 1992 to 2003, we captured and permanently marked 829 Dasypus novemcinctus (nine-banded armadillo) at the Tall Timbers Research Station in north- ern Florida. From 2004 to 2006, an attempt was made to eliminate all armadillos from Tall Timbers as part of an experiment to remove nest predators of Colinus virginianus (Northern Bobwhite). Data from armadillos killed at Tall Timbers during this period showed a rapid decline in previously marked individuals, with only 4 collected in 2006. Even though the resident population thus seemed to have been exterminated quickly, total numbers of armadillos collected remained stable over all 3 years. This did not appear to be due to an increase in reproductive success such that more juveniles were produced to replace the animals being lost. Rather, the data were more consistent with the hypothesis of immigration by adults into the population to colonize areas vacated by culled animals. This scenario supports previous reports of large numbers of transient armadillos that move extensively, and may provide insight into how armadillos have successfully invaded most of the southern United States in just the last 200 years. Finally, these findings also suggest that, at least in this area, culling animals is not likely to be an effective means of eliminating armadillo predation on quail eggs.