August 14, 2018 Vincent EC, Yoak AJ, et al. Comparison of field surveillance methods for and assessment of factors potentially associated with the presence of free-roaming cats in a mixed-urban environment. Am J Vet Res. 2018 Jul;79(7):745-754. These investigators compared two methods of surveying free-roaming cats by examining these methods in cats living near the Ohio State University campus. According to the researchers, the university campus and surrounding areas were divided into zones classified by land-use category; 100 zones were selected for surveillance of free-roaming cats by the line-transect method (with visual observation). Twenty-three of the 100 zones were selected for surveillance by the trail-camera method (motion-triggered still photography). Food resources in the study site were mapped, and the presence of other animal species was recorded with trail cameras. Potential associations between the number of cat sightings and variables of interest were assessed by statistical methods. The motion-triggered still photography captured 92 sightings of cats in nine zones compared with only six sightings in five zones by visual observation. Sightings correlated with the density of food resources (more food, more cats!) and more frequently at night. Identification of individual cats and estimation of population density was more difficult with these methods. The authors conclude, “Communities considering population control for free-roaming cats should consider the use of trail cameras to identify areas with high free-roaming cat activity and observation at night to gather baseline data. Easily accessible food waste may attract free-roaming cats.” it suggests that actions as simple as placing lids on dumpsters and removing food waste may help reduce numbers of free-roaming cats in a particular area. (MK) See also: Levy JK, Gale DW, et al. Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population. J Am Vet Med Assoc. 2003 Jan 1;222(1):42-6.