Turning into my driveway last night, I caught a glint of
yellow eyes and a flash of white fur.
Hitting the brakes just in time, I realized that my neighbor’s cat was
out again- and on the hunt. She crouched
at the side of the driveway, back hunched protectively, paws on the ground in
front of her. As I got out of the car and approached, distracting the cat, a
small, dark creature wriggled free from her grip and hobbled towards the safety
of the lawn. “Oh no,” I groaned. Our
local domesticated predator had struck again.
Many people wonder what they can do for conservation and how
they can make a real difference both in their community and globally. One
fairly substantial answer: keep your
cats indoors. While cats may look sweet
and harmless, they are natural predators, and the ancestors of domestic cats (and
feral cats today) hunted rodents, birds, reptiles, and other small wildlife to
survive. Pouncing is an instinct for cats, and when young cats “play with their
food” they may be honing their hunting skills- learning to time their strikes
based on the movement and distance of the prey item, coordinating their
movements to successfully capture their target.
Most cat owners whose cats roam free have come home to find
limp and lifeless “gifts” on their doorstep, or have observed their cat
sneaking up a tree in which a bird’s nest hides in the crook of a branch. But we usually only observe our cats killing
a few birds or mice- how much of an impact can this really have on wildlife
populations?
The answer is- plenty. One 2011 study by Anne Balogh, Thomas Ryder, and Pete
Marra showed that in Washington, D.C., predation accounted for 79% of all Gray
Catbird deaths, and almost half of the observed predation was attributable to
domestic cats. A 2003 study by Michael Woods, Robbie McDonald, and Stephen
Harris in Great Britain estimated that over a period of 5 months, domesticated
British cats brought home between 85-100 million prey items, including mammals,
birds, reptiles, and amphibians. In southeastern Michigan, a 2003 study
calculated that during the breeding season, free-ranging cats killed a minimum
of one bird per kilometer per day, for a total of ~16,000-~47,000 birds killed
over the course of the breeding season in this area.
However, the number of wildlife kills by cats is hard to
study, and much past research has relied on reports from cat owners. A new, innovative study attached “Kitty Cams”
to 60 cats in Georgia to record the cats’ behavior, day and night. The results were alarming. Although much of the scientific literature focuses
on the impacts of outdoor cats on bird populations, the Kitty Cams showed that among
these cats, 41% of prey items are reptiles, with mammals comprising 25% and
birds 12%. These clever cameras also
suggest that owner reports of cat kills are drastically underrepresenting the
impact of predation; only about a quarter of prey was brought home by these
cats, with almost half left to rot.
Many of us are familiar with the devastating effects that
invasive species can have on single species and entire ecosystems; in fact,
NatureServe identifies invasive species as the second biggest threat to
endangered species, second only to habitat loss. European gypsy moths caused hundreds of
millions of dollars of destruction in eastern U.S. forests, feral hogs have
devastated local plant communities in the Great Smoky Mountains National Park,
and the chestnut blight fungus of the late 19th century wiped out
almost every single chestnut tree in the eastern U.S. Domestic cats, too, are an invasive species,
and most wildlife communities are not adapted to avoid these skilled predators.
So, if you’d like to play a more active role in conservation in your community, consider keeping your cats indoors. Your cats will live longer, and your local
wildlife community will thank you.
For more information
about the Kitty Cam research, and to watch Kitty Cam videos, see:
For additional
information on domestic cats’ impact on wildlife, go to:
For an opinion piece
on how keeping cats outdoors is bad for both wildlife and the cats themselves,
check out:
One of North
America’s rarest and least known butterflies, the White Mountain Fritillary (Boloria montinus) makes it living exclusively
at or above treeline on the Presidential Range of New Hampshire’s White
Mountains. Isolated from its holarctic cousins for at least the past several thousand years, this 'endemic' butterfly’s extremely narrow range and unknown population size led to its 2008 listing as a state-endangered species. It is also a prime
candidate for conservation monitoring, which is where VCE enters the picture. VCE biologists Brendan Collins and Spencer Hardy made weekly
trips throughout July and August to Mt. Washington's famed alpine meadows and stunted krummholz forests,
with the goal of elucidating this
subspecies’ ecology and life history.
The duo logged many rugged miles (and took in countless breathtaking views) to survey fritillaries and their habitat at more than 100 point count
locations, which were concentrated around moist alpine snowbank communities. They devoted special
attention to documenting possible host plants, the discovery of which proved to be even more elusive than the butterflies themselves.
