Paige M. Schmidt

Survival, Fecundity, and Movements of Free-Roaming Cats

Abstract Free-roaming cats (e.g., owned, semi-feral, and feral) impact wildlife worldwide through predation, competition, and disease transmission. Baseline ecological information necessary for population management is lacking. We radiocollared free-roaming cats (feral, n = 30; semi-feral, n = 14; owned, n = 10) in Caldwell, Texas, USA between October 2004 and November 2005 and compared population demographics among sex and ownership classification. We found ranges and movements declined across ownership classes whereas survival and fecundity increased. Our findings suggest that human interactions (e.g., feeding) may result in high, localized free-roaming cat densities, which may concentrate feral cat impacts and should be considered when evaluating population control strategies.

Evaluation of euthanasia and trap-neuter-return (TNR) programs in managing free-roaming cat populations.

Global estimates of the number of domestic cats (Felis catus) are >400 million. Issues associated with free-roaming cats are of global importance because of animal-welfare and public-health concerns and impacts on native wildlife through predation, competition and disease transmission. In the United States, proposed control solutions for managing urban free-roaming cat populations include euthanasia and trap–neuter–return (TNR) programs. We evaluated control methods using a demographic population model for a 25-year period, with parameters estimated from an unmanaged, free-roaming cat population in Texas. We modelled euthanasia and TNR at 25%, 50% and 75% implementation rates and a 50 : 50 combination of euthanasia and TNR at 25%, 50%, 75% and 100% implementation rates for 0%, 25% and 50% maximum immigration rates. We compared final population size, total number of cats treated and treatment effort relative to population reduction. Population decreases were comparable among euthanasia, TNR and a 50 : 50 combination for all treatment rates when the immigration rate was 0%; however, they were higher for euthanasia at 25% and 50% maximum immigration rates. Euthanasia required higher treatment effort than TNR. Our results indicate that immigration must be prevented and high (>50%) treatment rates implemented to reduce free-roaming cat populations.

Population Estimation and Monitoring of an Endangered Lagomorph

ABSTRACT We conducted the most intensive estimate of the endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri) metapopulation to date using pellet surveys and capture—recapture methodology. We livetrapped 83 rabbits, evaluated 5 closed population models, and selected the model that best represented the data. We considered the variation in behavioral response model the best model and correlated (r2 = 0.913) its patch population estimates to patch pellet densities. From the prediction equation, we generated a range-wide metapopulation estimate of 317 rabbits, a western clade population of 257 rabbits, an eastern clade population of 25 rabbits, and translocated marsh rabbit populations of 35 and zero on Little Pine and Water keys, respectively. A subset of patches whose marsh rabbit subpopulations were last estimated in 1993 exhibited a 46% decline in abundance over 15 yr. Due to the low estimate of the eastern clade population, special effort should be initiated to avoid loss of genetic diversity. The prediction equation suffers from limited data at high pellet densities, patches with ≥5 pellets/m2. Future studies should investigate if the slope of the regression is indeed near 1 by sampling patches across the range of pellet densities, especially those with ≥5 pellets/m2. The equation provides managers a quick, efficient, and noninvasive method to estimate marsh rabbit abundance from pellet counts but the confidence of predicted rabbit densities from high pellet density patches is low.

Do Native Warm-season Grasslands Near Airports Increase Bird Strike Hazards?

Abstract Bird aircraft collisions (bird strikes) are a recognized safety hazard and land uses that attract birds hazardous to aircraft should be avoided on and near airports. Many airfields contain large areas of anthropogenic grassland habitats, often dominated by cool season grasses. Land managed as native warm season grasses (NWSG) potentially could increase bird strike hazards on and near airports by attracting hazardous birds and harboring small mammals that are prey for hazardous raptors. We investigated bird and small mammal communities at three NWSG areas and three adjacent on airfield grassland areas in western Ohio, U.S.A. to determine whether NWSG increased bird strike hazards. Species specific differences in bird abundance and density were evident between the two landcover types, presumably the result of differences in plant community characteristics. Seven species of birds were found exclusively in NWSG or airfield grasslands. Birds of species categorized as ‘moderate’ to ‘extremely high’ in regard to hazard (severity) level to aircraft accounted for only 6% and 2% of all birds observed in airfield grasslands and NWSG areas, respectively. Small mammal capture success was approximately three times higher in NWSG areas, although raptor abundance did not differ between the two landcover types. Our findings suggest that NWSG might be considered a viable land use adjacent to airfields; however, similar research at additional locations, including larger NWSG areas, should be conducted.