Cat and Birds

A new study on the impact of free-roaming house cats on bird populations has been released and a recent NY Times article describes the findings:

http://www.nytimes.com/2011/03/21/science/21birds.html?_r=2&src=me&ref=homepage

This is just one more in a long line of studies demonstrating the enormous impact free-roaming house cats have on birds. Some argue that the impact of house cats on bird populations pales in comparison to habitat loss and degradation as a risk factor for native bird populations, but free-roaming and feral cats are actually part of the impact of habitat loss and degradation due to expanding residential development. House cats can actually extend the habitat impact of residential development because they often hunt in adjacent remnant patches of natural habitat, such as woodlots and local parks. They also diminish the efforts of nearby homeowners trying to restore some of the lost habitat for birds on their properties through Audubon at Home and similar programs. Even if these cats stay close to home, they prey on birds and other wildlife that enter their owner's properties.

House cats are subsidized predators that don't face the same constraints nature places on wild predators. We take care of most of their needs, while wild predators must budget their energy between hunting, finding mates, caring for young, defending territory, avoiding predators, overcoming illness and other activities. Cats have the extra energy to indulge in "leisure hunting", while wild predators have to focus on capturing just enough prey for themselves and their young. Also, wild predator numbers in a given area are limited by factors such as the available prey, competition with other predators, availability of suitable habitat, and mortality from animals that prey on them. Because we take care of them, house cat populations can occur in far higher concentrations than is possible for wild predators.

If you have a cat that simply cannot tolerate being kept inside full-time, try keeping it inside until after breakfast and making sure that it is back in the house before dinner. This keeps it indoors during the twilight hours, when birds and other wildlife are most vulnerable to predation. Cat owners should also be aware that there is a new dog in town that poses a mortal danger to their pets -- the eastern coyote. Coyotes are now well-established in Northern Virginia and they tend to eliminate medium-sized predators, including house cats, that compete with them for prey.

Free-roaming house cats aren't the only risk to birds posed by humans and our activities, but, as the study in the NY Times article makes clear, they are a significant one. Conservative estimates of the annual toll on birds in the U.S. are 100-150 million and higher estimates go to 1 billion. Untold numbers of small mammals, reptiles and amphibians are lost as well. Ultimately, it is the cumulative impact of many factors -- cat predation, habitat loss and fragmentation, pesticides, building lights, climate change, among others, often operating in concert, that put bird populations at risk. We need to address all of these, but cat predation is one on which every cat owner can have an immediate impact .