How effective is the Birdsbesafe® cat collar at reducing bird kills by domestic cats?

The global decline of songbird populations is a well-recognized conservation issue. Domestic cats are estimated to kill approximately 2.4 billion birds each year in the United States alone – more than most other anthropogenic threats combined. As many pet owners are reluctant to keep their cats inside, collar-mounted anti-predation devices for domestic cats may be an important conservation tool. We examined the effectiveness of the Birdsbesafe® collar cover (BCC), a sleeve of brightly patterned fabric worn over a typical breakaway collar. The bright colors of the BCC are intended to alert potential prey to the cat’s presence. By combining data from two studies in New York (2014 and 2019) and one in Florida (2019), all of which used similar methods, we tested the hypothesis that the BCC effectively reduces avian mortality caused by cats of different ages and sexes in different hunting environments. We tested 94 cats over a 12-week period in New York in 2014 or 8-week periods in Florida and New York in 2019 during the bird breeding seasons; cats alternated 2-week periods with and without the collar. Across studies, we recovered 2.7 times fewer birds per cat with the BCC than without (P = 0.006). The BCC was more effective at a temperate latitude than a subtropical one (P = 0.047). There was no difference in the effectiveness of the BCC for cats of varying ages, sexes, or hunting environments. Our results suggest that the BCC could be one tool within a larger effort to decrease domestic cat predation of songbirds.