Residents of New York City beware — according to the New York Times, in 2021 there were more than 21,000 rat sightings reported, compared to 15,000 rat sightings over the same period in 2019.
Rats are frequently seen running across neighborhood streets, scampering through subway tracks, or hiding in bushes and piles of garbage bags. The significant increase in outdoor rodent activity is a lingering effect of the COVID-19 pandemic — namely the expansion of outdoor dining and sanitation budget cuts.
If you’ve seen rats loitering on or around your property, there’s a good chance that they’re coming from nearby burrows. In this article, we’ll discuss burrowing rats and how to get rid of them.
Do Rats Burrow?
Yes. rat burrows can usually be found near building foundations or underneath bushes and shrubbery.
The two most common species of rats in New York City are the Norway rat (Rattus norvegicus) and the Roof rat (Rattus rattus). Out of these two species, only the Norway rat is known to burrow. Roof rats prefer to nest off the ground in trees or in upper parts of buildings, such as attics.
Norway rats naturally burrow into the ground in an outdoor environment in order to shelter themselves from predators and harsh weather conditions. Newly established burrows typically contain one single rat family, which normally contains more than a dozen rodents.
Rats usually find new places to establish new burrows in the summer and fall. As a burrow becomes more populated, the rats will dig new tunnels and holes to act as additional entry and exit points.
What Does a Rat Burrow Look Like?
On the surface, a rat burrow appears as a small hole in the ground that’s usually about 2-3 inches across.
The largest ones are typically the main entry points. Smaller entry and exit points can sometimes be located underneath shrubbery, discarded items, or lawn waste.
If a burrow is active, the main entrance will likely be cleared of vegetation. Norway rats also create runways, which are worn down paths in the grass and greasy track marks along walls, that lead into the entrance of their burrows. You might also spot rat droppings along these runways.
How Deep Do Rats Burrow?
Norway rat burrows are usually between 12 and 18 inches deep. If the burrow is up against the foundation of a building, it may be as deep as 4 feet, allowing them to travel beneath the foundation and into the building.
Can Rats Burrow through Gravel?
It’s possible, but not very common.
In areas with gravel, there are usually fewer rats because they don’t prefer to burrow in it. Gravel limits their ability to conceal their movements and hide the entrance of the burrow. By comparison, in grassy areas rats are able to easily move around and burrow without drawing attention.
How to Get Rid of Burrowing Rats
When removing burrowing rats from your property, the first step is to address and remove the conditions that attracted them in the first place. Otherwise, they’ll come back and create new burrows.
- Start by removing any clutter that can be used as cover for rats to run around and hide.
- Trim bushes and other areas of overgrowth near buildings and sidewalks.
- Most importantly, eliminate potential food sources for rats. Keep trash in metal lidded cans and only take the garbage out to the curb on days it’s collected.
Another important step is to locate and close rat burrows. By filling up the burrows and sealing up the entrances, you can discourage rats from living near your property.
Not only does this destroy their home, filling a burrows disrupts the rats’ daily routine — something rats hate. Such a disruption often causes them to leave and find new areas to make their nest.
How to Fill Rat Burrows
- Look for signs of activity (i.e. the entrance is cleared of vegetation and you can see tracks, runways, or droppings).
- Stuff the entrance with steel wool or mesh wire if the burrow is active.
- Fill the hole with soil and dirt.
- Stomp it down or tamp down with a shovel.
If the burrow seems inactive — meaning it is empty or abandoned — simply use a shovel to fill the hole with dirt and then stomp it down. Wait a few days and check back to see if rats have dug back into the burrow. If so, then it is an active burrow.
If the burrow is active — meaning rats are living inside — caving it in with dirt isn’t enough because the rats will re-open it. In this case, you’ll need to stuff the entrances with steel wool to stop the rats from digging their way back in or out. Make sure that the steel wool is packed tightly so that rats aren’t able to chew through it.
Sometimes you might want to flush out the burrow first to force out any rats inside. You can do that by using a hose to fill the burrow with water. This stops the rats inside from digging new holes after you’ve close them.
Don’t attempt to fill the burrow with dry ice, poison, or bleach to kill the rats inside — this requires safe and proper application should be left to trained professionals.
How to Get Rid of Rat Burrows in Gardens
Since rats prefer to burrow in spaces in close proximity to food and water, a garden is a tempting location. Here are some ways to get rid of burrowing rats in your garden.
- Install sturdy wire mesh or chicken wire to block entry into your garden and compost bins.
- Place wire landscaping mesh approximately 1/2 inches below the soil around plants to prevent rats from digging.
- Keep compost into rodent-resistant bins with tightly-fitted lids.
- Keep plants trimmed and well-maintained.
- Remove clutter and garbage.
Professional Rodent Control Methods
These methods are used by pest control professionals to get rid of burrowing rats.
Dry ice is a potent tool for controlling burrowing rat populations used in New York City and other major U.S. cities. It can be packed into burrows before the holes are sealed to exterminate the rats inside.
As dry ice melts, it releases large amounts of carbon dioxide, which fills the burrow and suffocates any rats hiding within. This method is considered to be more humane than other extermination methods, and dry ice is also non-toxic and doesn’t release any harmful chemicals into the environment.
Untrained individuals or landlords should not attempt to use dry ice to control burrowing rats because it can be quite dangerous if not handled properly. Direct contact with dry ice can cause severe burns and frostbite.
Carbon Monoxide (BurrowRx)
Carbon monoxide is a colorless and odorless gas that reduces oxygen supply to the tissues and leads to hypoxia. At MMPC, our rat control technicians use a machine called the BurrowRx that pumps carbon monoxide through a nozzle into active rat burrows.
The BurrowRx machine includes a smoke oil tracer that makes the carbon monoxide gas visible, which helps the technician locate additional entry and exit holes where gas can be seen escaping. These holes are then closed with soil and any rats inside the burrow are humanely killed within minutes.
BurrowRx and other carbon monoxide machines should only be used by licensed and trained professionals. Carbon monoxide is a poisonous gas, and should only be used outdoors where there is no risk of smoke or exhaust getting indoors.
Rat Bait Stations
Rat bait stations can be placed near active burrows and other areas where you notice or suspect rat activity.
Bait stations are small, tamper-resistant plastic boxes with poisoned rodent bait inside. When used to control rats, professionals typically use slow-acting poisons, which contain anticoagulants that interfere with blood clotting and cause the rodent to eventually die from internal bleeding.
If you are dealing with an outdoor rat infestation on your property or in your neighborhood, MMPC is here to help! We have a team of licensed pest control experts with over 25 years of experience helping our fellow New Yorkers get rid of burrowing rats and other pests.