Editor: And now for another of my hobby horses, a major persecutor of our bird life... Phil Brown
Cats - domesticated pet or wild killer?
problems. Estimates of cats’ impact on bird numbers have consequently varied widely over the years and, speaking globally, the humble cat has also been blamed for the actual extinction of many bird species - 33 in all5. To confuse matters still further the Mammal Society has published a figure of 275 million animals being killed each year by pet cats in Britain6. Whereas the animal behaviourist John Bradshaw in his excellent book ‘Cat sense’7 in 2013 moderates this estimate with a much lower total, close to 130 million.
Domestic cats Cat with a ‘Great’ catch!
For years a finger has been pointed at the domestic cat as a bird assassin in our midst. Over ten years ago the late Chris Mead of the BTO arrived at a figure of over twenty million bird deaths per annum that could be attributed to UK cats (pers. comm.). Cats are undoubtedly extremely proficient hunters and many others since have hazarded a guess as to the annual total. For instance Chris Packham in 2012 asserted UK cats were responsible for 50 million bird deaths a year. As will emerge, the issue of measurement in this area is a fraught with
Surprisingly there is even debate concerning the total population of the domestic cat in the UK. John Bradshaw judges the total to presently be around 9 million8, but there are recent signs this total is rising. As the paragraph above demonstrates, estimates of their impact on birds vary even more widely. But, over the last five years, both here and in the States, there have been attempts at more rigorous research. Recently the Smithsonian Conservation Biology Institute (SCBI), along with the US Fish and Wildlife Service conducted a review of studies that had examined cats’ predatory prowess. Disturbingly this review concluded that cats “are the top threat to
5
Memorably the lighthouse keeper’s cat, ‘Tibbles’, who single ‘handedly’ saw off the nocturnal, flightless passerine, the Stephen Island Wren in 1894. But rats have also proved no less problematic, being responsible for or contributing to many other island species extinctions.
6
This figure is widely cited, even though the basis by which it was calculated has been shown to be flawed and grossly exaggerates their kill rate. In fact in 2003 a revised-down total of 92 million for a five-month period was issued.
7
‘Cat sense. The feline enigma revealed’ by John Bradshaw, Allen Lane 2013
8
In 2005 the market research company Mintel calculated it to be 7 million cats, then a telephone survey in 2007 estimated the UK households owned 10.3 million cats, whilst in 2013/4 the Pet Foods Manufacturing Association (PFMA) concluded there were 8-8.5 million. So Bradshaw’s estimate of 9 million seems a reasonable compromise.
T H E H AR R I ER – A ut um n 2 0 1 4
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