Pack Rat Nests: Finding Them and Dealing With Them
A tidy heap of sticks, cactus joints and odd bits of junk under the deck, in the shed or under the hood is a pack rat nest. Don't pull it apart by hand. Soak it with disinfectant first, trap the rat, seal the building it was getting into and then clear the nest.
Pack rats, or woodrats, are native, and they're common along Albuquerque's east and south edges. University of Arizona Cooperative Extension says a single nest site can be used for generations. The City of Albuquerque also lists pack rats among the rodents involved in plague locally, so a nest near the house deserves attention.
What a nest looks like
Extension describes woodrat nests as conspicuous and built from sticks, cactus and other organic debris. Inside is a midden, a central living and food storage area where layers of urine and droppings build up. From outside you'll see a mound of twigs, juniper bits, cholla and prickly pear pieces, seed pods and sometimes foil, bottle caps or a missing glove.
The rat itself has a furry tail, which separates it from a Norway or roof rat. The state rodent guide notes woodrats have well-haired, usually two-toned tails. Big ears, big eyes and a white belly are the other clues.
Where they build
Extension lists the base of a shrub or tree, the middle of a prickly pear and small caves in the wild, and attics, garages and the engine compartments of cars that sit in town. Around here that means:
- Under decks, portals and stored lumber
- At the base of junipers, chamisa and cholla along a back wall
- In woodpiles and rock piles
- In garages, especially behind shelves and the water heater
- Under the hood of a car, RV or tractor that sits
Why not just tear it out
Extension warns that hantavirus and other diseases can be present in woodrat nests, and says to soak a nest with disinfectant before disturbing it. It also says never to handle dead or dying woodrats bare-handed. In plague areas, fleas are the other concern: the New Mexico Department of Health tells people to avoid rodent nests and burrows and to use insect repellent outdoors.
So gloves, long sleeves, a good mask and a thorough soak come first. Never fling nest material or a dead animal with a shovel. If the nest is large, in an enclosed space or near where kids and pets play, it's a job to hire out. See pack rat control.
Getting rid of them for good
Extension calls exclusion and barriers the most effective method when woodrats are getting into buildings, and says trapping alone isn't a long-term fix. The usual order is trap, seal, then clear the nest. If you clear a nest without sealing the garage, another pack rat will move into the empty site.
Extension also discourages relocating woodrats. Released animals often die, and the nest gets reused anyway. Where real damage is happening, lethal trapping may be warranted after prevention steps.
Making the yard less inviting
Clear brush and rock piles near the house, keep firewood on a rack off the ground and away from walls, and don't leave pet food out. Trim junipers so the base is visible. The state rodent guide suggests keeping plants 3 to 4 feet back from buildings and a clean strip about 3 feet wide along the foundation. Homes in High Desert and Four Hills, where native landscaping runs right up to the walls, benefit most.
For engine nests, see rodents in cars and garages.
Nests in cars and engines
An engine nest is the most expensive kind. Pack rats carry sticks and cactus into the engine bay of a car that sits, and chew wiring along the way. The CDC's vehicle steps apply: air it out for 20 minutes with the hood and doors open, disconnect the battery before working in the engine compartment, soak the nest for 5 minutes and then remove it. Replace the air filter if nesting reached the intake. A mechanic should check the wiring.
Then deal with where the car sits. If it's in a garage, seal the door and corners. If it's in the driveway, clear brush nearby and use the car more often. See mice in RVs and campers.
Also asked
Why did a pack rat take my keys?
Woodrats pick up shiny or interesting objects and often drop them for the next thing they find. That habit is where the name comes from.
Is a pack rat the same as a roof rat?
No. Pack rats are native woodrats with furry tails. The state rodent guide says roof rats are generally found only in the southern Rio Grande Valley.
Will a repellent keep pack rats away?
Extension says a balsam fir oil repellent seems to help. It works best alongside trapping and sealing.
Should I report a dead pack rat?
In North Albuquerque Acres, east of Tramway, the foothills and the East Mountains, the city collects rodents that died without injury for plague testing. Call 311.
How big can a pack rat nest get?
Nests can grow large because sites get reused for generations, per University of Arizona Extension. An old nest may be a sizable mound of sticks and debris.