Interesting. If rodent and bird mortality from cats is generally compensatory, then perhaps the collar-based deterrents has benefits by allowing animals in good health time to escape while also allowing for predation of individuals in the “doomed surplus.” Just read some papers on the idea that low levels of predation has benefits to population growth (e.g. Sandercock et al. 2011), and am now curious as to whether individuals, on average, would be “functioning and feeling better” commensurate with change in population size… unknown.
Sandercock BK, Nilsen EB, Broseth H, Pedersen HC (2011) Is hunting mortality additive or compensatory with natural morality? Effects of experimental harvest on the survival and cause-specific mortality of willow ptarmigan. Journal of Animal Ecology 80:244-258. doi: 10.1111/j.1365-2656.2010.01769.x
Very interesting… particularly this point “The impacts of harvest on seasonal and annual variation in survival likely differ among populations and animal species
exposed to different sets of environmental conditions”. That is, whether mortality is compensatory or additive depends on context (as always.… ecology is just not easy to generalize).
I’m also really curious as to number of natural predators in areas were we expect high outdoor cat presence (e.g., low density housing) and how that plays out re compensatory and additive mortality.
your appendix certainly highlights how spatially-simple the Loss et al. 2013 estimate of cat-caused mortality is.… seems like their model could be improved by adding in a metric of urban landcover (e.g. LANDSAT impervious surface).… perhaps hotspots could be highlighted if compared against eBird and/or Partners In Flight data on avian abundance.… I similarly agree, as you allude to, there appear to be opportunities to use urban landcover as an approximation of predator-prey dynamics (via trophic structure, perhaps), but also pitfalls given hyper-local contexts. thanks for the opportunity to think out loud here ….. :)
Interesting. If rodent and bird mortality from cats is generally compensatory, then perhaps the collar-based deterrents has benefits by allowing animals in good health time to escape while also allowing for predation of individuals in the “doomed surplus.” Just read some papers on the idea that low levels of predation has benefits to population growth (e.g. Sandercock et al. 2011), and am now curious as to whether individuals, on average, would be “functioning and feeling better” commensurate with change in population size… unknown.
Sandercock BK, Nilsen EB, Broseth H, Pedersen HC (2011) Is hunting mortality additive or compensatory with natural morality? Effects of experimental harvest on the survival and cause-specific mortality of willow ptarmigan. Journal of Animal Ecology 80:244-258. doi: 10.1111/j.1365-2656.2010.01769.x
Very interesting… particularly this point “The impacts of harvest on seasonal and annual variation in survival likely differ among populations and animal species exposed to different sets of environmental conditions”. That is, whether mortality is compensatory or additive depends on context (as always.… ecology is just not easy to generalize).
I’m also really curious as to number of natural predators in areas were we expect high outdoor cat presence (e.g., low density housing) and how that plays out re compensatory and additive mortality.
your appendix certainly highlights how spatially-simple the Loss et al. 2013 estimate of cat-caused mortality is.… seems like their model could be improved by adding in a metric of urban landcover (e.g. LANDSAT impervious surface).… perhaps hotspots could be highlighted if compared against eBird and/or Partners In Flight data on avian abundance.… I similarly agree, as you allude to, there appear to be opportunities to use urban landcover as an approximation of predator-prey dynamics (via trophic structure, perhaps), but also pitfalls given hyper-local contexts. thanks for the opportunity to think out loud here ….. :)