A rodenticide, zinc phosphide, was applied to remove black-tailed prairie dogs (Cynomys ludovicianus) from 6 ha of a prairie dog colony in southwestern South Dakota. Another adjacent 6 ha was left untreated. The removal experiment was repeated two consecutive years. Contingency table analysis showed that the resultant population was not homogeneous; age classes by sex of the immigrant and resident subpopulations were different (P < 0.01). The ratio of adult females to yearling females was greater among immigrants than among residents (P < 0.03). Female immigrants did not produce young in the treated zone during the year of their arrival. Fewer of these females displayed distended nipples than expected (P < 0.01), indicating that these immigrants did not reproduce during the reproductive season immediately preceding dispersal and suggesting that failure to reproduce may have stimulated dispersal.
Cincotta, R. P.; Uresk, D. W.; and Hansen, R. M.
"Demography of black-tailed prairie dog populations reoccupying sites treated with rodenticide,"
Great Basin Naturalist: Vol. 47
, Article 22.
Available at: http://scholarsarchive.byu.edu/gbn/vol47/iss2/22