New York City rodentologist Bobby Corrigan shares six useful strategies for achieving the best results in rodent control work.


As most pest professionals know, rodent control is rarely easy. Mice and rats are responsible for some of the industry’s highest callback rates. Yet, despite the complexity of these mammals, we have learned from research that having a good understanding of a few specific rodent behaviours can help us to provide highly skilled rodent control services. This short article discusses six of my own favourite ‘rodent behavioural steps’ for buildings and outlines how we can use them to our advantage.


Step 1: Perform behavioural observations on all rodent jobs

There is no such thing as a ‘standard rodent job’. Being observant does not simply mean looking around with a bright flashlight. It means concentrating on the infestation’s possible origin, locating the rodents’ high activity areas, identifying their primary food and water resources, and the rodents’ primary daily travel routes within the building, to name but a few.

To do this, certain ‘observational words‘, as I call them, can help you to scientifically zero-in on the above. The pay-off for being keenly observant is enormous because it provides you with Google Map pin drops as to where you should inspect as well as the best locations for installing exterior and interior equipment.

Six important observational inspection words to always keep in mind on the job include:

  1. Shadows. Rodents are constantly scurrying towards the shadows to remain hidden from their enemies.
  2. Corners. Mice and rats feel comfortable and safe in corners; thus they are always visiting and investigating the corners they encounter.
  3. Lines. Rodents follow linear tunnels, vines, wires, edges of building supports, and exterior and interior perimeter wall-floor junctions.
  4. Warmth. Except for the warmest months of the year, rodents prefer to reside in the warm zones inside our buildings. Warm environments are especially important for mother rodents looking to rear their pups, as they require a warm zone to survive while they are waiting to grow their fur.
  5. Quiet and undisturbed zones. Rodents repeatedly seek out rooms and areas inside buildings that are quieter than the surrounding areas. Such areas often mean less disturbance by enemies and make for attractive nurseries for the females.
  6. Pheromones. Rodents rely heavily on the scent (body odours) of their families and colony members to find food and other rodents for reproduction and territorial maintenance. Rodents leave their pheromones in their droppings and urine. Where you notice accumulations of droppings or urine, these are good places to install traps and bait stations.


Step 2: When using rodenticide baits, keep them fresh

Our baits are meant to offer rodents a food reward, right? Well, rodents have exceptional senses of taste. If your baits become contaminated from some pesticide odour in your service vehicle, or from some other contaminant from your gloves, rodents will reject feeding on the bait, and thus the time and effort spent installing the bait will be wasted. Keep your baits protected while in storage or in transit and always be careful when handling baits to avoid contamination.


Step 3: When using snap traps, vary the food lures amongst the traps

Rats and mice are like us; they like variety in their diet if they can get it. It is not true that peanut butter is their favourite food. The most important lure bait for traps is to match whatever on-site food it was that they first suckled from their mother’s milk. Add to this, the opposite food groups of that first bait (proteins, carbs, sweets). During hot summer days, always offer food lures that offer the rodents moisture.


Step 4: For rodent initials, schedule the first visits close together.

The primary reason for rodent callbacks is because we underestimate the size and distribution of the infestation. When using baits, the second service should be 5-7 days after the initial visit. For trapping programs, traps should remain baited but unset for 4-5 days to allow for the family and/or colony members to become familiar with them. Once set, revisit at service intervals of 5-14 days depending on the severity of the infestation.


Step 5: The hard-to-reach sections of buildings must be inspected and serviced

Some portions of our buildings can be attractive to rodents, but difficult (and thus time-consuming) to access (e.g. crawl spaces and suspended ceilings). Nevertheless, they must be monitored and possibly serviced.


Step 6: Stay up to date with new technology and research

Advances in technology and research are coming along faster than ever. Just taking a look at the advertisements in Professional Pest Manager magazine each issue likely proves the point.

An important example is the advent of remote rodent sensors. Sensors can be installed in the hard-to-reach zones, removing the need for constant checking by the servicing professional. What is spent on the addition of the sensors is easily saved in the amount of time spent accessing these areas each service visit.

Additionally, with the power of the internet (e.g. Google, Twitter, Facebook, Research Gate, etc.), all one needs is to insert a few key words (e.g., ‘feeding behaviour, rats’), and you can remain abreast of the latest research with a simple click. (I myself use Twitter to update rodent science and behaviour, hopefully of practical use ($$) to pest professionals. You can follow me @Rodentologist.) Discovering a new trap, bait, or other tool online can quickly put you ahead of your competition, which translates to higher profits.

Make no mistake, pest management is a complex science. But it is also an exciting occupation because of its constant advances in both business and science. I hope these six steps help you to advance your own company’s rodent pest management.

My thanks to Professional Pest Manager magazine for this invitation to contribute. And also, to each of you for keeping Aussies everywhere safe and healthy through your essential work day in, day out.

More information on rats and mice.


Bobby Corrigan, Ph.D., Urban Rodentologist


The ultimate rodent control handbook

New York City rodentologist Bobby Corrigan (pictured) has over 30 years’ experience working in the urban and industrial pest management industries. His popular book ‘Rodent Control: A Practical Guide for Pest Management Professionals‘ provides a comprehensive look at rodent biology and behaviour and the various approaches for control. Available from PCT Store.