The Impact of Targeted Trap-Neuter-Return Efforts in the San Francisco Bay Area

Abstract

Recently, a growing collection of evidence that associates trap-neuter-return (TNR) programs with substantial and sustained reductions in community cat populations across a variety of environments has emerged. Peer-reviewed studies emanating from the northeastern, midwestern, and southeastern United States, as well as Australia, document such reductions. The present study expands upon this body of evidence by examining the impact of a long-term TNR program on a population of community cats residing on a pedestrian trail adjacent to an oceanic bay located on the West Coast of the U.S. A population of 175 community cats, as determined by an initial census, living on a 2-mile section of the San Francisco Bay Trail declined by 99.4% over a 16-year period. After the conclusion of the initial count, the presence of cats was monitored as part of the TNR program's daily feeding regimen. Of the 258 total cats enrolled in the program between 2004 and 2020, only one remained at the end of the program period. These results are consistent with those documented at the various sites of other long-term TNR programs.

Keywords: community cats; feral cats; free-roaming cats; nonlethal management; population reductions; stray cats; trap–neuter–return (TNR).

Figure 1

Reduction in Project Bay Cat (PBC) population over 16 years, indicating a starting population of 175 cats with one cat remaining at the end of the study period. Data prior to July 2009 (indicated by filled circles and dashed lines) was obtained from annual reports; later, more detailed data was obtained from feeding station log books.

Figure 2

Histograms illustrating the proportion of the most common modes of disposition: adoption, foster care, and relocation ((A), n = 127); disappearance from site ((B), n = 60); death ((C), n = 31); and euthanasia ((D), n = 35).