The number of pet cats (Felis catus) on a densely-populated oceanic island (Gran Canaria; Canary Archipelago) and its impact on wild fauna

Abstract

The cat (Felis catus) is a very popular pet, however, it is also an invasive species with a remarkable ability to prey on wildlife. Due to their predatory nature, both domestic cats with access to the outdoors and stray and feral cats have an impact on local fauna. To date, no studies have been conducted on the impact of stray or domestic cats in the Canary Islands, only on the impact of feral cats. The main objectives of the present study were to assess the number of domestic cats living in homes on the island of Gran Canaria and to estimate their impact on local wildlife using anonymous surveys. According to the Animal Identification Registry of the Canary Island (Zoocan), there are 28,541 domestic cats identified with microchip in Gran Canaria, but the results of our study indicate that only 54.2% of the owned domestic cats are identified with this method, so their real number might be around 52,658 cats. Of these, 17.3% regularly bring prey home. On average, each of these cats preys on 27.5 (24.1–30.9) prey/year, which translates into 1,667,706 (1,566,329–1,768,482) prey/year for all the owned cats on the island: 751,257 (705,589–796,654) mammals, 632,222 (593,790–670,426) reptiles, and 284,834 (267,519––302,046) birds. These data indicate that pet cats without adequate control may be a conservation concern for the native vertebrates of Gran Canaria and indicate that it is necessary and urgent to articulate actions and legislation to properly manage free-roaming cats, limiting their numbers and improving their control.