Your Pet Guide

The domestic cat is probably a significant predator of birds. Current UK assessments indicate that they may be accountable for an estimated 64.8 million bird deaths each year.

Certain species appear more susceptible than others; for example, 30% of house sparrow mortality is linkmd to the domestic cat. In the recovery of ringed robins and dunnocks, it was also concluded that 31% of deaths were a result of cat predation.

On islands, birds can contribute as much as 60% of a cat’s diet. In nearly all cases, however, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances eradication of cats has caused a ‘mesopredator release’ effect; where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey.

Domestic cats are, however, known to be a contributing factor to the decline of many species; a factor that has ultimately led, in some cases, to extinction. The South Island Piopio; Chatham Islands Rail; the Auckland Islands Merganser; and the common diving petrel are a few from a long list, with the most extreme case being the flightless Stephen Island Wren, which was driven to extinction only a few years after its discovery.

Some of the same factors that have promoted adaptive radiation of island avifauna over evolutionary time appear to promote vulnerability to non-native species in modern time. The susceptibility inherent of many island birds is undoubtedly due to evolution in the absence of mainland predators, competitors, diseases and parasites.

In addition to lower reproductive rates and extended incubation periods. The loss of flight, or reduced flying ability is also characteristic of many island endemics. These biological aspects have increased vulnerability to extinction in the presence of introduced species, such as the domestic cat.

Equally, behavioural traits exhibited by island species, such as ‘predatory naivety’ and ground-nesting, have also contributed to their susceptibility.

Cats are a cosmopolitan species and are found across much of the world. They are extremely adaptable and are now present on all the continents (including Antarctica) and on 118 of 131 main groups of islands.

Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas and wetlands. Their habitats even include small oceanic islands with no human inhabitants. However, this ability to thrive in almost any terrestrial habitat has led the cat's designation as one of the world's worst invasive species.



Despite this general adaptability, the close relatives of domestic cats, the African Wildcat (Felis silvestris lybica) and the Arabian Sand Cat (Felis margarita) both inhabit desert environments, and domestic cats still show similar adaptations and behaviors.

To date, there are few scientific data available to assess the impact of cat predation on prey populations. Cat numbers are growing annually and their abundance is far above the ‘natural’ carrying capacity, due to their population sizes being independent of their prey’s dynamics – i.e. cats are ‘recreational’ hunters.

Population densities can be as high as 2000 individuals per km2[155] and the current trend is an increase of 0.5 million cats annually. Even well-fed domestic cats may hunt and kill, mainly catching small mammals, but also birds, amphibians, reptiles, fish and invertebrates.

Hunting by domestic cats may be contributing to the decline in the numbers of birds in urban areas, although the importance of this effect remains controversial. In the wild, the introduction of feral cats during human settlement can threaten native species with extinction.

In many cases controlling or eliminating the populations of non-native cats can produce a rapid recovery in native animals. However, the ecological role of introduced cats can be more complicated: for example, cats can control the numbers of rats, which also prey on birds' eggs and young, so in some cases eliminating a cat population can actually accelerate the decline of an endangered bird species in the presence of a mesopredator, controlled by cats.

In the Southern Hemisphere, cats are a particular problem in landmasses such as Australasia, where cat species have never been native and there were few equivalent native medium-sized mammalian predators.

Native species such as the New Zealand Kakapo and the Australian Bettong, for example, tend to be more ecologically vulnerable and behaviorally "naive" to predation by feral cats. Feral cats have had a major impact on these native species and have played a leading role in the endangerment and extinction of many animals.

Female cats are seasonally polyestrous, which means they may have many periods of heat over the course of a year, the season beginning in January or February and ending in late October. Heat periods occur about every two weeks and last about 4 to 7 days.

Multiple males will be attracted to a female in heat. The males will fight over her, and the victor wins the right to mate. At first, the female will reject the male, but eventually the female will allow the male to mate. The female will utter a loud yowl as the male pulls out of her.

This is because a male cat's penis has a band of about 120-150 backwards-pointing spines, which are about one millimeter long; upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation. After mating, the female will wash her vulva thoroughly.

If a male attempts to breed with her at this point, the female will attack him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat. Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate.

Furthermore, cats are superfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers. The gestation period for cats is between 64–67 days, with an average length of 66 days.

The size of a litter averages three to five kittens, with the first litter usually smaller than subsequent litters. Kittens are weaned at between six and seven weeks, and cats normally reach sexual maturity at 5–10 months (females) and to 5–7 months (males), although this can vary depending on breed.

Females can have two to three litters per year, so may produce up to 150 kittens in their breeding span of around ten years. Cats are ready to go to new homes at about 12 weeks old, or when they are ready to leave their mother. Cats can be surgically sterilized (spayed or castrated) as early as 7 weeks to limit unwanted reproduction.

This surgery also prevents undesirable sex-related behavior, such as aggression, territory marking (spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed prior to puberty, at about three to six months. In the USA approximately 80% of household cats are neutered.