The figures are based on a collation of many studies. It is dangerous to make bold statements about the impact of roaming domestic cats on wildlife. There are many articles on the subject, a high proportion of which are frankly misleading due to bias and “estimations” and “extrapolations”. All rather pointless to be honest. These figures are the best I have seen but they only indicate the diet (the sorts of animals preyed upon) of roaming domestic cats who eat live prey. There is no comment on the extinction of any species because of domestic cats. That is a very complex subject which is abused by people with an axe to grind.
The full description is:
Average frequency of occurrence of mammals, birds and reptiles in the diet of the domestic cat based on gut or scat (feces) analysis in relation to cats in the northern hemisphere, meaning Europe and N.America combined, and on islands with and without seabirds.
This is a quote from the excellent book: The Domestic Cat: The Biology of its Behavior (I have it on Kindle):
“Careful studies are still needed before ‘condemning’ all cats to an indoor life, or even forbidding them as pets.”
The hunting success rate of the domestic cat – a very successful predator is good. They require only between two and five pounces to capture prey. The success rate depends on the prey species. The wait before the pounce is important and a factor in success.