Exclusion is, by far, the preferred and most effective strategy when dealing with snakes in and around the residence or other occupied structures. When coupled with proper vegetation management or other habitat modifications in the area that lies immediately adjacent to those structures, problems with snakes entering the home should be minimized substantially.
Snakes are seeking one of several interests when entering a structure. One may be to secure food, which in most cases means that they are following and attempting to prey on rodents. If you have openings or gaps in the shell of the building that can allow a mouse, rat, or other small animal or large insect into the building (generally an opening size greater than 1/4 inch), then many of our native snake species can follow the scent trail laid down by rodents and will be able to get in as well. Sometimes snakes enter a building looking for a secure, constant-temperature environment in which to deposit their eggs or to bear their young. Finally, snakes may enter a structure simply for the security it provides for resting or when digesting a recent meal. Regardless of reason for their entry, the best approach to solving this problem lies with locating and closing off or permanently sealing all existing entry points with “chew-resistant” materials. Use of such materials is aimed not at snakes per se but at rodents that will gnaw through less substantial barriers and thus open the way for snakes to re-enter.
If you have any doubts about whether the openings are being used by snakes, rodents, or stinging insects, then don't seal them off. Never secure an opening unless you are certain the opening is no longer being used. Better to wait and monitor than trap unwanted creatures in.
Examples of places to investigate include points of entry for utility services (e.g., electric, telephone, or cable service lines; natural gas service, water supply lines), clothes dryer, bathroom, or kitchen exhaust fan vents; gaps beneath or around doors or cellar windows, and places where the structure’s sill plate no longer lies flush on or has rotted away from the foundation. Additionally, the vegetation or habitat that occupies the area just outside of or immediately adjacent to where you locate such openings needs careful examination for the role it may play in fostering use by these animals. Thick, lush vegetation that lies directly against a building provides great cover to rodents, snakes, and other animals as they search for points of entry into the building. By thinning or selectively removing some of that vegetation, you will reduce the security these animals feel while also increasing the potential effectiveness of predators on those species. Predators will be able to see prey better and have greater unrestricted access to them.
Although several repellent products currently are registered for use on snakes (i.e., products consisting of ground sulfur and naphthalene powder) and are available commercially, the extant literature and research findings have yet to demonstrate any degree of success among these products in terms of their ability to keep snakes away from a treated area. Hence, their use cannot be recommended at this time.
Resources (online):
Reptiles
Exclusion Tips
