Rodents
Rodents
  - Norway rat
  - Roof rat
  - House mouse
Economic and
Health impacts
I.P. Management
This page will look at rodent pests at farm. Their potential impact on health and production. A detailed integrated management programme for effective control will be outlined.

• Roof rat •
• House mouse •

Does the farm have a rodent problem?

It is likely that mice or rats inhabit most farms. If nothing is done about the problem, a rodent population can cost the farm a lot of money. Rats breed quickly. A healthy female can produce up to six litters a year, each of 8–10 young with offspring attaining sexual maturity in 8–12 weeks. Mice breed at a similar rate. At any time as many as 30% of females in a population may be pregnant. Timely control is essential to limit the cost of an infestation.


The signs of rodent infestation:

Characteristic
What to look for
Sounds Gnawing, climbing noises in walls, squeaks.
Droppings Look along walls and rafters, behind objects and near food supplies
Burrows Rat burrows are indicated by fresh diggings along foundations, through floorboards and into wall spaces
Runs Look for dust-free areas along walls and behind storage material
Gnawing marks Look for wood chips around boards, bins and crates. Fresh gnawing marks will be pale in colour
Rodent odours Persistent musky odours are positive sign of infestation
Visual sighting Daylight sighting of mice is common. Rats are seen in daylight only if populations are high. Quietly enter the shed at night, wait in silence for five minutes and listen for the sound of rodent activity. Look around with a powerful torch; rat eyes will reflect the light
Smudge marks These may be found on pipes or rafters where dirt and oil from rats' fur leave a greasy film


Is it a rat or mouse problem?

Since rats and mice require different control strategies you should determine if rats or mice are the problem. The simplest way to differentiate the type of infestation is based on droppings. Mouse droppings are black and rice-kernel size, whereas rat droppings are black and bean-sized.
Rodent faeces
• Norway rat •
• Roof rat •
• House mouse •

Physical and behavioral characteristics of adult rats and mice

Characteristic
Norway rat
 Roof rat
House mouse
Size (including tail) 42 cm 17 - 25 cm 16 cm
Average weight (adult) 450 gm 260 gm 20 gm
When active nocturnal nocturnal nocturnal
Sight poor (1.5m) poor poor (1 m)
Smell, touch, taste excellent excellent excellent
Hearing highly accurate highly accurate highly accurate
Range from nest 40 - 50 m 40 - 50 m 3 - 10 m
Fear of new objects 3-7 days 3 - 7 days .05-5 hours
Water requirements daily daily 2-4 days without
Food per day 20 - 30 gm 15 - 22 gm 3 gm
Favourite foods cereals, meat, fish, garbage vegetables, fruits, cereals grains, rolled oats, sugar, raisins
Droppings 18 mm blunt 12 mm pointed rice size
Minimum width for entrance
(hole diameter )		 12 mm   6 mm
Can chew through
(given edge to gnaw on)
rubber, aluminium, plastic, wood
 same as rats

 
   
 
 
 
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