Roof Rat Pressure Is Rising

It’s the other rat. The rat that prefers to stay high in the shadows. The one that may never touch the ground its’ entire life. What rat is this? Meet the roof rat.
Roof rat concerns are on the rise in every place on the I-5 corridor, from Washington State to Southern California. Facility and property managers bring attention to this threat, and take pro-active steps to combat the threat.
“Roof rat populations have been growing in recent years and they have done so under the radar of most QA and property managers,” says Ashley Roden, training specialist for Sprague Pest Solutions. “They are cryptic animals and will remain hidden in high, out of the way locations within a structure. People simply do not notice their presence.”
Roof rats can spend their entire life above ground in areas inside a building structure:
  • Exposed beams and pipes
  • Hidden pipe chases and utility lines
  • Wall voids and drop ceilings
  • Concrete cinder blocks
  • On top of shelving units
  • Overhead electrical junction boxes
  • On top of or inside equipment (they have been found inside large ovens in commercial bakeries)
  • Raised and false floors 

On the exterior of a structure, roof rats will establish nests in the dead fronds of unmanaged palm trees, on fence ledges behind thick overgrown vines and vegetation, within dense overgrown trees and vegetation, and in wood piles, lumber stacks or shipping pallets stacked outside loading docks.
Their choice of living accommodations makes roof rats difficult to manage. Roden advocates inspections and treatments get done using lifts and ladders; these are more time and labor intensive.
“Since we have to use ladders and lifts to gain access to rarely visited, out of the way locations inside a structure, clients have to stop production.  This can be an inconvenience, but nothing compared to a failed audit or product recall due to rats contaminating the food,” adds Roden.  
Roof rats are excellent climbers and thus can access and fit into more places within a facility.  They are more neophobic than Norway rats and will avoid “new” items including bait stations and snap traps. Roof rats are opportunistic eaters and will feed on seeds, nuts, fruits, berries, insects, seafood and pet food.
What can commercial property and QA managers do to help reduce the roof rat threat?
Roden and the technical team at Sprague is educating our clients on the differences between Norway and roof rats. We recommend these roof rat prevention tips:
  • Keep Watch Over Maintenance Issues – Engage with your facility maintenance staff to make sure doors and windows are properly sealed and above ground openings on the roof (i.e. HVAC units, ventilation and utility openings, shingles, etc.) and along the roof line are not providing access points.
  • Sanitation – If your facility is not on top of its sanitation programs, you are asking for trouble with rodents and other pests. Poor sanitation practices are the leading attractant for them. Work with your cleaning staff or cleaning contactor to make sure food processing and transportation equipment and production areas are frequently cleaned and sanitized. Stressing and educating the importance of good sanitation with employees is also important.
  • Good Inventory Management – Practice first-in, first-out inventory management to avoid allowing rodent damaged product to remain high on shelves and providing a ready-made food source.
  • Inspect Incoming Shipments – Carefully inspect incoming shipments for signs of rodent infestation to avoid introducing roof rats (and other rodents and pests) in to your facility.  

What can commercial clients expect when it comes to rodent pressure as we enter prime breeding season?
Roden says milder winters, readily available food sources and disruptive construction activity will fuel a spike in rodent activity in and around commercial facilities.
“Facilities used to be concerned with rodents primarily in the fall and winter but they have emerged as a year around threat,” says Roden. “Preventing rodents from establishing a foothold inside your facility is essential. You can achieved it by knowing what conditions to look for – both physical and cultural – that promote rodent activity, and how to eliminate them. .”

Rodents: Rats & Mice