Wet weather causes Rats to invade family homes

Cooler temperatures and wet weather cause rats to seek refuge in warm homes this Autumn. Tidiness in your garden is a must so don’t leave waste around your home. The Pest Control Association says rat sightings in people’s homes are set to rise as they abandon their summer habitats to seek food and shelter indoors.



The Brown Rat (Rattus norevegicus) is most common and poses the greatest threat to human health and hygiene. They can severely damage building structures due to gnawing of electrical cables, drains, sewers and can destroy food stores. Rats can carry many food borne pathogens e.g. bacteria, protozoa and fungi. Rats are incontinent which helps mark their territory and spread disease e.g. Leptospirosis or Weil’s disease as it is better known is transmitted in their urine to humans. In damp conditions or locations, it is transferred through cuts in the skin. The flu like symptoms which can result in organ failure or death. Other diseases include bubonic plague, rat bite fever or salmonella.


The brown rat has small eyes and ears, brown to grey colour back with lighter underside. Its tail is shorter than its body and head. Sexually mature at 3 months, having 3-6 litters per year with an average litter size 8-10 young with an average life span of 12 months. They breed rapidly to form large infestations, eating a large amount of food in a wide range of locations. They may hoard or drag food to a safe location and they require a large amount of liquid in their diet. Rats cannot vomit and they are incontinent which can result in animal feed or foodstuff contamination.


Mainly active by night or during the day if disturbed. They can burrow underground and travel along familiar paths leaving smears close by walls or pipes.  They will often have a toilet area for waste which can be detected under ultraviolet torches – glowing a blue white if fresh or yellow white if old. A very important factor in rat control is their aversion to new objects (neophobia) in their environment. It can last for 10-14 days and may greatly lower the efficiency of control measures dependent on level of neopobia. Other signals of their presence include droppings, gnawing, footprints or tail swipes.


The average house has more than a dozen ways for rats to enter. They can fit through a space as small as 15mm such as plumbing, unscreened vents or gaps in the eaves and roof edges. Homeowners should start rodent-proofing their homes as soon as possible. Inspect properties thoroughly, removes nesting sites or areas of harbourage. Keep bins well maintained with lids closed and don’t leave leftover food lying around. Areas around bird feeders should be kept clean and pet food should not be left out overnight.


Call us for a site survey (086) 812 0435.

Mervyn Walsh, Field Conservation Biologist