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Suburban cats and wildlife
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Suburban cats and wildlife
Paton's questionnaire
A more reliable survey
Detailed study in Canberra
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Detailed study in Canberra

The most detailed study was conducted by Barratt (4, 5), and involved cats in Canberra suburbs bordering nature reserves. He not only asked owners to estimate the prey caught by their cat(s) in the previous 12 months, but also to keep a daily record of prey over a 12 month period. Data were available on 138 cats.

There was a huge variation between cats:

  • 70% caught less than 10 prey a year
  • 6% caught over 50 a year
  • bells on the collar had no effect on the number of prey taken.

Sleepcat

An average of 10.2 prey per cat per year were recorded, made up as follows:

  • Mammals 6.9 (99% introduced)
  • Birds 2.6 (42% introduced)
  • Reptiles/amphibians 0.7
  • Total 10.2

Rats and mice made up 63% of the total prey. Among birds, the most common species were house sparrows, blackbirds (introduced), silver eyes and crimson rosellas (native). Populations of all these species are high, so much so that 10,000 crimson rosellas and 20,000 silver eyes are killed each year in Canberra as pests. Therefore, there is no sign that populations of the most heavily preyed upon birds have declined. Barratt notes (5):

"...predation estimates alone do not necessarily reflect relative impacts on different prey types. Nor do apparently high rates of predation prove that prey populations are detrimentally affected, particularly in highly disturbed and modified environments. For birds, at least, habitat-related factors may be substantially more important in determining communal structure in suburbs than predation by house cats."

This conclusion is an important counterbalance to Paton's emotive claims. It is interesting to note too that estimates of their cat's hunting behaviour made by Barratt's interviewees were twice as high as the actual prey recorded, another important limitation to the Paton study.

If statements are made about cat behaviour and the environmental impact of cats, they should be based on properly conducted scientific investigations, and not clouded by hatred of cats.