As with any target pest, having a good understanding of its behaviour, including food preferences, allows for much more successful baiting.
A good understanding of pest behaviour can make a huge difference in the level of success and speed of control in a treatment program. This is especially the case with rodents. Understanding their general feeding behaviour – how much they eat, how much they eat in a single sitting, the distance they will travel from the nest, as well as population levels and colony structure, all impact bait placement and replenishment intervals.
Rats are often considered to be ‘cautious avoiders’ or neophobic, which means they tend to frightened of or avoid new things. Rats may tend to avoid bait stations and traps for a few days until they become accustomed to the disturbance. So don’t be surprised if it takes rats 1-2 weeks to start to take bait.
That said, it is not unknown for rats to totally consume baits on the first night if the bait is palatable and other food sources are rare. This highlights a typical rat feeding behaviour in that when rats do feed, they typically tend to gorge themselves at only one or two locations. Rats are capable of eating 30g of bait in a sitting!
As a result of this behaviour, if a significant infestation is suspected more frequent visits to re-bait should be planned – the initial baits may be quickly eaten out by a few rats (often the more dominant rats), leaving the remainder to keep breeding!
With rats commonly travelling 30-100m from the nesting site, bait stations can be placed up to 15m apart. Place the stations at harbourages and feeding sites or along their runways. Rats are unlikely to leave their known foraging routes. Once in place, don’t keep moving the stations – with their neophobic nature this unsettles the rats.
Sometimes, pest managers blame the rats’ cautious behaviour for the fact that the rodents aren’t consuming the bait. However, you need to assess whether there are other potential food sources available. Attractive as most commercial rodent baits are, rodents are sometimes just not interested in grain-based bait while there are numerous more attractive foodstuffs to be found.
When there is intense food competition, you will need to rely more heavily upon proofing, hygiene, traps and glue boards.
In contrast to rats, mice are ‘curious investigators’ and will explore a new environment much more rapidly than any rat species.
The curious nature of mice is of assistance when trying to eradicate an infestation by either rodenticides or mechanical means. They are omnivorous in their feeding habits and will eat small amounts at many locations and at frequent intervals, accumulating 3-5g per day.
In contrast to rats, mice often won’t travel more than a couple of metres from the nest to a feeding site. As a result, baits stations or traps need to be placed every couple of metres. Typically you need more bait stations but with less bait to deal with a mice infestation, compared to a rodent infestation at a similar sized properties.
Placing the stations along wall floor joins or in the corners of the room (where mice tend to run) and between the nest and their current feeding sites are the best locations.