Whether it’s squirrels or mice and rats, rodents invade homes regardless of the season. However, wintertime drives them indoors where it’s warm and they can raid pantries and cupboards. These pests spread diseases and leave behind feces as they invade your living areas, making them a threat to your family and home.

Squirrels:

The northern palm squirrel (Funambulus pennantii), also known as the five-striped palm squirrel, is native to northern India where it lives around houses and causes damage to fruit and vegetable crops. The northern palm squirrel is introduced to Australia, and is established in Perth, Western Australia (WA). Until 1976 it was also established in Sydney, New South Wales in the locality of Taronga Zoo and a small population was established in Kew Gardens, Melbourne, Victoria.

squirrel

In 1898, the squirrel was deliberately released in the grounds of the WA South Perth Zoo, as an enhancement to the park. Although the squirrel remained confined to the zoo grounds for many years, animals dispersed naturally and by human activities to an area of about 30km² outside the zoo grounds. Individual squirrels have also been located in other Perth suburbs and occasionally in country localities.… we have possums though. Possums are cute but VERY loud at nighttime

Mice:

Field mice rarely venture into inhabited buildings but in the winter months, they will go into outhouses and sheds where fruit and vegetables are stored.

Field mice are a big threat to businesses operating in farming and agriculture but is not prevalent in Australia.

  • Size: adult head and body 80 – 100mm in length; Tail 70 – 90mm.
  • Weight: Male can weigh 25g, and the female 20g.
  • Sandy / orange brown fur on the head and back.
  • Yellowish fur on the flanks and white on the belly.
  • There is usually a small streak of yellow on the chest.

Lifecycle

  • Their lifespan averages two to three months, but they can survive as much as 20 months in the wild, or two or more years in captivity.
  • Breeding seasons are October/November to March/April and gestation lasts approximately 25 days. They grow their first fur after six days; their eyes open after 16; and they are weaned at around 18 days old.
  • Survival of the young and adults is poor during the first half of the breeding season as adult males can be aggressive towards one another and to the young, who are then driven from the nest.

Habits

  • They eat a high proportion of the seed crop of trees such as oak, beech, ash, lime, hawthorn and sycamore. Numbers can reach plague proportions in the grain belt areas.
  • Small snails and insects are particularly important sources of food in late spring and early summer when seeds are less available.
  • They also eat apples and will attack newly planted legume seeds

 

mouse

 

House mice are active all year round, which means you could find them invading your home or business at any time.

  • Size: 70 – 95mm in length, with a tail around the same length.
  • Weight: 12 – 30g.
  • Their relatively small feet & head and large eyes & ears distinguish them from a young brown rat (Rattus norvegicus).

Lifecycle

  • 4 – 16 young per litter; 7 – 8 litters a year.
  • Gestation period of about 3 weeks.
  • 8 – 12 weeks from birth to sexual maturity.

Habits

  • Usually ground living and burrowing, but often climbs.
  • Preferred food is cereals.
  • Will eat around 3g of food a day and can survive without any additional water. They will drink up to 3ml a day if their diet is particularly dry.

rats

There are currently over 60 described species of rats in Australia, and they occupy a wide range of the habitats across the country. The majority of these are native species; however two rats (Black Rat and Brown Rat) are introduced species that have rapidly adjusted to Australian conditions.

The widespread and abundant Black Rat (or Roof Rat, responsible for London’s Bubonic Plague in 1665), is a commensal rodent that is usually found in disturbed or degraded environments. It is the rat most commonly observed in cities and towns, and is often responsible for the infestation of houses, sheds, warehouses and storages.

 

brown rat

Diet
Most rats are granivorous (primarily seed-eaters), with an herbivorous diet the next most common form. Generally, rats are omnivores and will consume a range of food items depending on availability.

Habitat
Human intervention, in the form of clearing unsuitable habitats and planting cereal and other food crops, increases the optimal habitat and food resources for rats. An example is the native Canefield Rat, a grassland species that has increased in range due to the conversion of native rainforest habitats (unsuitable habitat) to sugarcane, where the soft soil and abundant food and shelter has enabled them to build up to “pest” levels, and hence cause crop damage.

Rat Biology
The Black and Brown rats, together with about six native rats, have a rapid life-strategy based on high birth rates, short life-spans and high death rates.

The large litters (up to 12 per litter) are born at a young age (approximately 21 day gestation), have minimal parental care, and are independent at an early age (21 days until weaned). These individuals are generally sexually mature and ready to breed at around 10 weeks.

These rats are capable of producing ten or more young every three weeks under ideal conditions. This breeding base can lead to rapid overpopulation and allows them to exploit optimal conditions, causing damage in cropping situations if population numbers become high.

The majority of native rats, however, are slow-breeding animals, with small litter sizes, regular breeding seasons, longer gestation and weaning periods, and lower juvenile mortality rates. These rats generally occur in non-cropping habitats and are therefore not considered to be “pest” species.

Temperature and food supply are known to be limiting factors for breeding, and often the season is extended when the temperature is moderate, and food readily available.

Rats require the protein in weed and grass seeds to maintain breeding condition, and early seed production can lead to an early commencement of the breeding season. Suppression of weed and grass growth in-crop is required to restrict the available food source and habitat area for rat breeding and development.