Back in January house and feral
Cats kill between 1.4 and 3.7 billion birds and between 6.9 and 20.7 billion mammals (mostly mice, shrews, rabbits, squirrels and voles) each year, a recent study reported. But what about
Joelene Hughes and David W. Macdonald, both of Oxford University, took a close look at the literature about dogs and their interactions with wildlife. As it turns out, the world's 700 million dogs damage wildlife and ecosystems as well, though no studies offered clear figures as to the extent.
They are killing animals and even infecting them in diseases. A few examples of the disaster that is free-roaming dogs, from LiveScience:
... in the late 1980s, researchers found that a single German shepherd on the loose in New Zealand's Waitangi State Forest was responsible for killing up to 500 kiwis. The dog had a collar, but was unregistered, and its owner was not found.
In another example from 2006, 12 ownerless dogs were thought to be wiping out populations of the
"Despite the increasing recognition of the potential problem dogs may create for wildlife, few solutions to conservation issues were offered by the literature reviewed, particularly to non-disease related problems," Livescience quotes from the paper, published in the journal Biological Conservation. "Local people and authorities may be reluctant to undertake dog population management or control because of the close nature of dog-human relationships."