A typical residential yard bounded by solid fencing is, ecologically speaking, an island. The wildlife that uses it — the opossums foraging under shrubs, the rabbits at the garden margins, the skunks moving through at night — are all animals that evolved in landscapes without hard boundaries. Their movement patterns require access to resources spread across a network of adjacent territories: feeding areas, denning sites, water, shelter, and escape cover. When a six-foot wooden fence panels a yard completely, that network is cut and the yard becomes a closed system that most animals cannot exit or enter without risk or considerable effort. The wildlife that does enter is effectively trapped until it finds a way out.
The solution is not to eliminate fencing. Fencing serves real purposes — privacy, pet containment, garden protection — and those purposes remain valid. The solution is strategic modification that allows small mammals to pass through while preserving the fence's primary function.
Eight Fence Modifications That Work
- Ground-level passage gaps: A 6-inch gap left at the base of one or more fence panels during installation — or cut retroactively into existing panels — allows opossums, rabbits, skunks, and most small mammals to pass through freely. The gap is nearly invisible from normal viewing angles and does not compromise fence stability or privacy.
- Raised panel corners: At fence corners where two panels meet, leaving a triangular ground-level opening of 4 to 6 inches provides an access point that wildlife find reliably and use repeatedly once established on their regular route.
- Climbing boards for opossums: A board or short section of rough-textured lumber leaned against the interior of a fence at a 45-degree angle allows opossums — capable but not graceful climbers — to scale and descend a fence they cannot otherwise manage. Position a board on both sides to allow passage in both directions.
- Mesh size guidance: If wire mesh is part of the fence design, openings of 4 by 4 inches or larger allow rabbits and adult opossums to move through without entanglement. Smaller mesh traps rather than excludes. If the goal is to keep out specific animals such as deer while allowing smaller species to pass, a lower-height exclusion barrier combined with a taller open mesh achieves this selective effect.
- Avoiding barbed wire: Low-strung barbed wire used to reinforce fence bases entangles small mammals and can cause injuries that are fatal. If a physical deterrent at ground level is needed to discourage digging, smooth galvanized wire or hardware cloth bent into an L-shape and buried just below the surface is a non-injurious alternative that achieves the same deterrent effect.
- Gap spacing at fence posts: Where fence panels attach to posts, the post itself sometimes creates a tighter-than-intended closure at the base. Leaving posts slightly proud of the panel edge on one side, or using a washer-style spacer, maintains the intended ground gap rather than allowing it to close during installation.
- Escape ramps at water features: In yards where ponds or water features are enclosed by fencing, a ramp made of rough stone, textured board, or stacked flat rocks leading from the water's edge to the fence gap allows small mammals that fall in to exit without drowning. This is particularly important for hedgehogs where they occur but benefits any small mammal that might fall into a steep-sided pond.
- Marking passage points: Wildlife find and reuse established entry points. Once a gap is established and used, placing a flat stone or piece of bark at the entry helps the access point persist if grass or debris accumulates. Small animals will continue to investigate marked surfaces that match the character of existing routes.
Which Species Benefit Most
Opossums benefit most from climbing boards and ground gaps, as their mobility is limited by their body plan — they are built for slow, deliberate movement rather than leaping or digging. A fence with no passage options effectively excludes them from the area entirely. Rabbits use low ground gaps and appropriately sized mesh openings almost immediately after installation. Skunks, which can dig but prefer not to, adopt passage gaps at ground level quickly and integrate them into regular foraging routes within days.
Ground-foraging birds — thrushes, towhees, and robins — also benefit from ground-level gaps, primarily by reducing entanglement risk during low-level flight along fence lines at night. Species that require larger corridors, such as foxes and deer, do not benefit from these small-mammal modifications; for those species, habitat connectivity requires landscape-level decisions beyond a single property.
The Neighborhood Corridor Effect
The benefit of passage gaps multiplies with adoption. A single yard with a ground-level gap allows an opossum to move through that property, but if neighboring yards are fully closed, the animal still cannot navigate the larger block. When three or more adjacent properties adopt compatible passage points at roughly aligned positions along their shared fence lines, the collective result is a corridor — a navigable route through otherwise fragmented residential landscape.
Wildlife camera data from urban ecology studies has documented opossums and rabbits using aligned passage points across three and four adjacent yards in sequence, following routes that could not exist if even one property in the chain had no access point. The coordination required is minimal: a conversation with a neighbor about gap alignment, or a street-level agreement on a shared standard, achieves a landscape-level connectivity benefit at essentially no cost per household. The individual modification is trivial; the collective result is a functional wildlife corridor running through the neighborhood.