Graduation Date

Fall 2020

Document Type



Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Dr. Richard Brown

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Daniel Barton

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

David Garcelon

Third Committee Member Affiliation

Community Member or Outside Professional

Subject Categories

Wildlife Management


The colonization by rats (Rattus spp.) and cats (Felis catus) on islands are known to contribute to the decline of native birds. On the island of Rota, Commonwealth of the Northern Mariana Islands, cats are being lethally removed to conserve two endangered bird species. Although cats are controlled to reduce impacts on birds, they can also prey heavily on sympatric rats. Of euthanized feral cats on Rota, 60% had ≥1 rat in the stomach. Predation by cats could be a mechanism of top-down control of rats. Removing feral cats may reduce the magnitude of that control, leading to increased rat abundance and, in turn, predation on native birds. To determine if the level of cat control being conducted on Rota is positively influencing rat abundance, I conducted a robust design capture-mark-recapture of rats, using a before-after-control-impact design, in two areas where the ongoing cat removal was not being conducted. Between primary rat trapping occasions, feral cats were removed from one of the two rat trapping areas. Using program MARK to model the data and Akaike information criterion to rank the models I determined that there was no effect of cat removal on the apparent survival of rats and that the estimated abundance did not change significantly in either the control or treatment groups after cat removal.

Citation Style

Journal of Wildlife Management


Thesis/Project Location