Domestic cats in Urban Environments: Should an Invasive Apex Predator be allowed to stay on the hunt?

Domestic Cats (Felis silvestris catus; Felis catus) are a human commensal, said to have started their relationship with us during the era of the first settled farmers (approx. 12.000 years ago) within the Fertile Crescent region of the middle east.¹ We took them into our homes and slowly transformed them into the royalty that a lot of us humans gladly serve to this day. We are often at their beck and call, in part thanks to their supposed exploitation of our innate bias towards the cries of our offspring.² Our feline overlords occasionally like to thank us for our servitude with an unsolicited gift, also known as that disgusting carcass of a dead bird they brought home after a successful hunt. How does this hunting behaviour effect the local urban wildlife? Are our feline companions driving local populations of prey to total extirpation and what tools are available in order to manage this issue?

Effects on Urban Ecology

Domestic cats influence their local urban ecology mainly through predation. The predation of wildlife introduces competitive pressure to local predators, whilst repressing the ability of prey species to take advantage of breeding or foraging opportunities (i.e. landscape of fear; LOF).³ They are also spreaders of certain zoonotic diseases, such as rabies and toxoplasmosis. Most studies focus on the direct effects of predation, while important indirect consequences of domestic cat predation such as those mentioned above remain relatively understudied.⁴  Greater consideration for these indirect effects has however luckily been on the rise in recent years. All together, domestic cats have contributed to the extinction of 63 species globally, possibly more.⁵  A summary of direct and indirect effects of domestic cat predation can be seen in the image below.

 

Species affected are diverse, including birds, mammals, fish, reptiles and even invertebrates. Although there are studies which indicate a preference for birds and mammals, when compared to reptiles and invertebrates. Important to note however, is that these studies were all carried out within locations that had a temperate climate, where birds and mammals may be more readily available to domestic cats in comparison to other types of prey. Beyond climate, there are several other factors which can influence the rate and composition of prey. These extrinsic and intrinsic factors are summarised in the image below.

The urban environment majorly influences predation rates per individual, which are likely to be less than to those of rural areas, which may be due to the smaller home range of urban domestic cats (daily mean: 1,94 ha).⁶ Another factor influencing urban predation rate may also be the higher density of cats within urban areas, perhaps allowing the total predation rate within said area to exceed that of rural sites. Relative prey composition also differs due to the smaller home range, along with the availability of cover for effective hunting and elements which may attract prey (e.g., trees).^{7, 8}

How to Manage Predation?

In order to prevent this predation behaviour from becoming associated with even more extinctions than the 63 species that are currently known, it should be managed. Methods for reduction of predation succes to be employed by owners include receiving more food of animal origin at home, equipping cats with noise making collars such as bells and allowing cats to use a play tower at home. These individual measures can be divided into three categories, which are shown in the image below.

Devices and deterrents, such as a bell collar, may only be effective at reducing predation for certain types of prey. The above mentioned bell collar reportedly decreases predation succes on mammals, but not birds. An explanation for this may be that cats are able to adjust their hunting strategies in order to reduce the effectivity of the bell collar. This explanation falls in line with the report that CatAlert, a collar-mounted sonic warning device reduces successful predation on birds by 51%. There are also collar attachments that are either visually based or based upon physical blockade of effective pounce movement, such as the brightly colored BirdsBeSafe collar cover and the CatBib, which is are both effective at reducing predation for birds specifically and to a lesser extent overall.⁹

In order to address the indirect effects of domestic cat predation, access management through permanent or semi-permanent restriction of access to the outside may be employed. Enrichment of the indoor environment may also reduce hunting success rates, although direct evidence of this remains obscured. Methods for enrichment include changes in food quantity and quality, along with facilitation of natural foraging and hunting behaviour via placement of physical objects to hide in or interact with (e.g. play towers, mesh tunnels) and through play. Playtime may reduce problematic cat behaviour, although association between enrichment and hunting succes rates is very understudied. Lack of responsible ownership practices, such as providing a litter box, increased the chance of cats bringing home prey in Chilean urban households and may provide evidence that enrichment could reduce hunting rates.^{9, 10}

Conclusions

All in all, our feline royalty is responsible for quite the disturbance of urban and non-urban ecology, both through direct predation and indirect fear effects.^{3, 4, 5} Measures may be taken by individual cat owners in order to mitigate these effects, such as fitting their cats with anti-predation devices, management of access to the outdoors and enrichment of the home environment. Effectiveness of these measures is either mostly for only certain types of prey or has yet to be researched properly.^{7, 8, 9} Public debate on the management of cat predation management of owned, free-ranging cats contains a great diversity of opinions, from those that see hunting as a natural behaviour that should not be interfered with to those that were unaware of any problems caused by this behaviour.¹¹ What is your opinion on this issue? Should domestic cats be allowed be continue their hunt untouched? Or should we introduce  new legislation in order to push cat owners into taking measures, perhaps via subsidies or law enforcement? Speak your mind in the comments below!

 

References:

4. Magle, S. B., & Crowther, M. S. (2023). Editorial: Ecological impacts of domestic cat activity on wildlife. Frontiers in Ecology And Evolution, 11. https://doi.org/10.3389/fevo.2023.1282679

5. Loss, S. R., & Marra, P. P. (2017). Population impacts of free‐ranging domestic cats on mainland vertebrates. Frontiers in Ecology And The Environment, 15(9), 502–509. https://doi.org/10.1002/fee.1633

6. Thomas, R. L., Baker, P. J., & Fellowes, M. D. E. (2014). Ranging characteristics of the domestic cat (Felis catus) in an urban environment. Urban Ecosystems, 17(4), 911–921. https://doi.org/10.1007/s11252-014-0360-5

7. Cordonnier, M., Ferry, N., Renaud, E., Maurice, A., Bonnaud, E., & Baudry, E. (2022). Drivers of predation by pet cats: environment overcomes predator’s intrinsic characteristics. Urban Ecosystems, 25(4), 1327–1337. https://doi.org/10.1007/s11252-022-01231-w

8. Mella-Méndez, I., Flores‐Peredo, R., Amaya-Espinel, J. D., Bolívar‐Cimé, B., G, M. C. M., & Martínez, A. J. (2022). Predation of wildlife by domestic cats in a Neotropical city: a multi-factor issue. Biological Invasions, 24(5), 1539–1551. https://doi.org/10.1007/s10530-022-02734-5

9. Cecchetti, M., Crowley, S. L., & McDonald, R. A. (2020). Drivers and facilitators of hunting behaviour in domestic cats and options for management. Mammal Review, 51(3), 307–322. https://doi.org/10.1111/mam.12230

10. Escobar, S., Alegría-Morán, R., Calderón-Amor, J., & Tadich, T. (2019). Can Responsible Ownership Practices Influence Hunting Behavior of Owned Cats?: Results from a Survey of Cat Owners in Chile. Animals, 9(10), 745. https://doi.org/10.3390/ani9100745

11. Crowley, S. L., Cecchetti, M., & McDonald, R. A. (2020). Diverse perspectives of cat owners indicate barriers to and opportunities for managing cat predation of wildlife. Frontiers in Ecology And The Environment, 18(10), 544–549. https://doi.org/10.1002/fee.2254