Male cats, or tomcats, become sexually mature anywhere from roughly 4 months in age to a year or slightly longer. Unlike female cats, toms don't experience heat cycles. However, you will certainly know it if an unfixed male is ready for the attentions of queens!
In general, tomcats go into full sexual maturity around 6 or 7 months in age, although it varies. Early bloomers are possible though, and some little ones reach "adulthood" at 4 months, some at around a year or so. From this point on, healthy tomcats are able to successfully breed with females for well over a decade in most cases!
Tomcats who live outdoors spend a massive portion of their daily routine on the lookout for females. Apart from seeking females to mate with, many of them search also for food -- unless they have homes or designated caretakers. In search of females, male cats cover a lot of turf, often traveling miles away from a "home base." This is especially common behavior during the breeding season, which starts around January and ends during the autumn.
Male cats are very hormonally driven and often display signs that they are ready to mate! These telltale -- and often annoying -- signs include urine spraying and persistent yowling. The cats yowl in order to call out to females in the vicinity. The vocalization is also common when the boys detect the scent of a female in heat. When tomcats smell a female, they will stalk and chase persistently -- often to her dismay!
Feline overpopulation is a serious and growing issue that affects communities all across the country and world. If you are the owner of a male cat that spends a lot of time outdoors, take the time out to neuter him. Not only will you be doing your part in preventing often-unwanted kittens from being born, you will be saving yourself -- and your fluffy boy -- a lot of the stress and hassle that comes from mating behaviors! Consider doing the same for any feral cats in your neighborhood, too. Trap-neuter-release efforts are practical solutions for keeping homeless cat populations to a minimum.