For example, to lessen a common Australian city's population of 700,000 feral cats as a result of TNR would need sterilising at the very least 500,000 of them originally, and then continuing to sterilise more than 75% of the kittens that the other 200,000 would proceed to make just about every calendar year indefinitely, along with all the new recruits from other cat populations drawn by the food provide.