Estimating free-roaming cat populations and the effects of one year Trap-Neuter-Return management effort in a highly urban area

Free-roaming cat populations are increasing in urban areas around the world. Management strategies remain controversial, as attempts to rapidly minimize the impact of cats may conflict with finding an ethical means of population reduction in this domesticated species. Trap-Neuter-Return (TNR) is a non-lethal strategy which can theoretically lead to population decline with an ethical approach. The present study aimed to estimate free-roaming cat populations and also to measure the efficacy of a one-year TNR campaign in a highly urban area. Using a sight/resight methodology, we examined free-roaming cat populations in four sites across two neighbourhoods (Harlem and Bedford-Stuyvesant) in New York City. Sampling was repeated after 1 year, during which an intensive TNR effort occurred in each of those areas. Results from this study found population estimates range from 2.6-4.1 cats/km. Additionally, we found between 78-98% turnover in each study area. After one year of TNR, the proportion of sterilised individuals in our treatment sites increased to 50%. Model results suggest there is no evidence that sterilised individuals are more likely to be encountered, indicating that sterilisation may not affect movement patterns of cats. Free-roaming cats occur at high densities at all study sites, though populations varied, even within the same neighbourhood. We found evidence of considerable migration within study sites, which further complicates the application of a sterilisation management strategy. Management strategies directed toward free-roaming cats, such as TNR, may require a broad-scale approach, involving different facets of the community and should occur over multiple years.     

Happily ever after? Fates of translocated nuisance woodchucks in the Chicago metropolitan area

Urban Ecosystems - Human-wildlife conflict is increasing as urbanization expands and wildlife species adjust to living near people. Translocation is often used to manage human-wildlife conflict...     

Survival,abundance, and capture rate of eastern cottontail rabbits in an urban park

Eastern cottontail rabbits (Sylvilagus floridanus) are common, conspicuous denizens of urban environments. They are associated with human-wildlife conflict due to vegetation damage. Prior to this study, population dynamics of this species in urban environments remained largely uncharacterized. For three consecutive winters, we used classic field ecology methods (mark-recapture and mark–resight surveys) to estimate demographic parameters of rabbits in a city park in Chicago, Illinois. Rabbits occurred in densities as high as 16.3 rabbits/ha, which is comparatively high for the Midwestern United States. An annual survivorship of 30.4?±?12.9 % SE was similar to that observed in natural environments in similar climates. This result refuted our hypothesis that urban rabbits would have higher annual survival rates than rabbits in natural settings due to food subsidies supplied by landscaping in parks. Mean distance between trap locations for rabbits trapped three or more times was 43.14?±?30.01 m SD, suggesting that rabbits in the urban study area had smaller home ranges than rabbits in non-human-dominated habitats. This study contributes to our understanding of population dynamics of a human-wildlife conflict species in urban environments and provides useful information for managers dealing with damage caused by rabbits. The mark-resight method employed here could be used by managers to estimate pre- and post-management population sizes of other conflict species, for example Canada geese (Branta Canadensis), in parks and green spaces, provided that the species is trappable, visible, and individuals have relatively small home ranges.     

Urban predator–prey association: coyote and deer distributions in the Chicago metropolitan area

We examined how predator or prey presence, as well as local and landscape factors, influence the distribution of coyotes (Canis latrans) and white-tailed deer (Odocoileus virginianus) in the Chicago metropolitan area. We collected data for 2 years at 93 study sites along 3 transects of urbanization using motion-triggered cameras. Our primary objective was to determine the relationship among coyote and deer spatial and temporal distribution, habitat characteristics, and human activity using multi-season patch occupancy models. Coyote occupancy was most strongly linked to rates of site visitation by humans and dogs, and was more likely farther from the urban center, with coyote colonization of sites inversely related to road density, housing density, and human and dog site visitation. Deer more frequently occupied sites with high canopy cover near water sources and colonized smaller sites with reduced housing density and human and dog presence. Expected predator–prey dynamics were altered in this highly urban system. Though we predicted deer would avoid coyotes on the landscape based on an “ecology of fear” framework, deer and coyote occupancy showed a strong positive association. We suggest that a scarcity of quality habitat in urban areas may cause the species to co-occupy habitat despite potential fawn predation. Modifying human foot traffic in green spaces may represent a useful tool for management and conservation of large urban mammals.