Sterilising Males and females
There is still this feeling among some caregivers that it is okay to just sterilise the females and not the males. While it is true that obviously females are the ones that actually give birth, males need to be sterilised too.
Male cats are the ones that fight, that spray and are the reason why a lot of the nuisance complaints come in. This jeopardises your entire colony. They are also in much better health when you sterilise them - they're less prone to cancers, and of course FIV and FELV which are spread through fighting and mating among other things. It will improve the overall health of your colony to get them sterilised.
Male cats may also just wander off if your females are all sterilised - and this means they'll be impregnating some other female cats somewhere else, so please get your males done as well.