Too many cats in my garden?!?

I have a neuteured 13 year old tomcat. Recently we've had a cute little female cat coming in and 'talking' to him, now we have an unneuteured male cat hanging around and ANOTHER male (not sure if he's snipped) also hanging around. She is making yowling noises and is only interested in my cat, who ignores her. The other two males aren't interested in her but only in my cat and occasionally there are a few scraps. Is she in season? If so, should I do anything? Why are the other males ignoring her and interested in my cat? Thanks!