Rodents of many types can cause damage in urban settings and especially agricultural land. Population control, such as contraception, can sometimes be used to reduce damage without killing the rodents themselves. Most rodents, as it goes with many small sized creatures, have short live spans and breed rapidly; for these reasons contraceptive controls can reduce populations in a short amount of time.
Unfortunately orally consumed birth control for rodents is not available to the average consumer. This kind of approach is used most often in large scale agricultural settings, or sometimes in urban settings, though administered by a county or city agent. The chemicals used are most often 20,25-diazacholesterol, 22-azacholesterol, and aromatase inhibitor. Like I said, though, these are only available to specially permitted entities.
Farmers, park managers, foresters, and other government workers can use birth control methods to reduce rodent pest populations. But what about homeowners?
The most common method is to use rodenticide baits such as anticoagulants, zinc phosphide, burrow fumigants such as gas cartridges. Of course these are lethal, killing the rodents, and often emitting harmful toxins into the surrounding soil. What are your other options?
Locate where the pest is living. If it is in your home, garage, or shed, clean out the area where the nest is located. Also be sure to seal any holes or cracks where small pests can enter the protected areas of home or other covered structure.
Keep all food, garbage, and pet food inaccessible to pests. Many pets foods are kept in the garage, or bowls are even placed outside in the yard. Nothing could make life easier for a possum or raccoon than a bowl of food left out at night! Keep bags of pet food in sealed containers, and keep garbage, compost, and even fallen fruit from trees in a compost bin or other appropriate container.
You can use an organic or biodegradable poison for pests. Yes this still kills them, but it does not harm the surrounding environment. You can also choose a human live trap to capture them. Of course then you have to decide where to release the pest. Unless you have an enemy that lives away from your neighborhood, the decision is difficult!