Rodent Control in Palo Alto, CA

Local Context

Roof Rats Arrive Over Palo Alto's Canopy, Not Under Its Foundation

Palo Alto is a city of mature trees, and roof rats (Rattus rattus) are a canopy animal. They climb. In Crescent Park, Old Palo Alto and Duveneck/St. Francis, decades-old plums, walnuts, citrus and ornamentals put branches within jumping distance of a roof, and once a rat is on the roof it works the weak points: a gap at the fascia, an unscreened attic vent, the void where a plumbing stack passes the sheathing. Fruit on the ground keeps the population fed; the tree only supplies the route.

The two ends of the city add their own routes. Along the Baylands Nature Preserve and the eastern edge near US-101, the marsh and slough margin supports rodents that move toward structures when the ground floods in winter, and Norway rats work storm drains and utility trenches under the commercial blocks on University and California Avenue. On the west side, houses that back Pearson-Arastradero Preserve and the Foothills preserve take mice off the grassland at the first cold nights, when lows drop into the high 30s.

Construction type decides how bad it gets. Eichler and post-and-beam houses in Greenmeadow and Fairmeadow have low-slope roofs and shallow or nonexistent attics, so rodents end up in a furred-down soffit, a mechanical chase or the garage ceiling rather than a walkable attic — harder to see and harder to reach. Pre-1930 houses in Professorville have the opposite problem: full attics and sub-areas with a century of settling, siding gaps and old vent screens.