Rats Along Creeks and Greenbelts: A Woodinville Guide.

A rat does not wander across open lawn if it can avoid it. It follows edges, such as the base of a fence, the line of a hedge, the bank of a creek or the foot of a retaining wall. Along those lines it feels sheltered, and it learns the route by scent and touch.

A creek provides water, and the brush along its banks provides cover. A greenbelt behind a row of houses provides the same, and every fence line leading off it is a side road. The result is that properties at the edge of a green corridor see traffic that properties in the middle of a block may not.

Both Norway rats and roof rats are found in the Puget Sound region. Norway rats are heavier and stay low. They dig burrows beside foundations, under decks and sheds, and in the bank of a drainage ditch. Roof rats are lighter and climb. They use branches, fences and utility lines to reach roofs.

A corridor supports both. Norway rats use the ground-level cover and water, while roof rats use the trees above. If your lot touches a corridor, the plan has to consider both the ground and the canopy.

• Burrows about two inches wide along fences, foundations and banks.
• Worn, greasy paths along a fence or wall.
• Gnawed fruit, nuts or chicken feed.
• Droppings along runs and under cover.
• Rats seen at dusk on fences or wires.

The boundary between a greenbelt and a yard is where most activity starts. Fallen fruit, spilled bird seed, compost and pet food act as bait, and a rat that finds one source returns every night. A shed, a woodpile or a deck gives it somewhere to live while it does so.

From there, the next step is the house. A rat will test the foundation, the garage door and the roof edge until it finds a gap. A half-inch opening is enough, and a branch touching the roof is an open bridge.

Start with food. Move bird feeders away from the house or bring them in at night, and use a tray to catch seed. Pick up fallen fruit and nuts each week in season. Use a closed compost bin instead of an open pile, and never add meat or oils to it. Keep pet food indoors.

Next, cover. Cut back dense groundcover and shrubs that touch the foundation, aiming for a visible gap along the wall. Stack firewood off the ground and a few feet from the house. Remove piles of debris, old pallets and stored materials that make a shelter.

Last, the structure. Seal the gaps at the foundation, the vents and the roof edge. Trim branches back from the roof. Our rat control page describes the full plan, and backyard and outdoor rodent control covers the yard side.

Walk the edges of your property in daylight. Look along fences, under decks and sheds, and beside the foundation. Fresh burrows are smooth and clean, with no cobwebs or leaves. If you find one, do not fill it in. A rat trapped underground will dig out elsewhere, and you lose the clue to where activity is.

Take a photo, note the location and describe it on the call. We map active burrows and runs, place traps along them and fill them only after activity stops.

A greenbelt is shared, and so is the problem. If your neighbor leaves feed out, your yard may see the traffic. A friendly conversation about food and trash helps more than any amount of trapping in a single yard. Share what you have found, and compare notes.

Some neighborhoods coordinate. When several homes on a street tidy their yards and seal their houses in the same season, the whole pressure drops, because the animals have nowhere easy to go.

Fences with a gap beneath them are highways. A deck with open space below it is a ready-made den. Sheds raised only a few inches off the ground give rats a dry nest. Closing the gap beneath a deck with hardware cloth buried a few inches into the soil is a simple and lasting fix.

Check them each spring. Wood softens and shifts, and a gap that was not there last year may be today.

Rat activity changes with the season. Autumn pushes rats toward buildings, and spring brings new litters. A walk around the lot in late summer and again in early spring catches problems before they grow.

If you find signs, call. Early action is simpler and cheaper than trying to clear an established colony.