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C ATS IN D O O RS
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www.abcbirds.org
C
ATS IN
D
O
O
RS
How many animals do domestic cats
kill each year in the United States?
Exact numbers are unknown, but scientists es-
timate that nationwide, cats kill between 500
million and one billion birds1 and billions more
small mammals such as rabbits, squirrels, and
chipmunks each year. Cats kill common species
such as the Northern Cardinal, Blue Jay, and
House Wren, as well as rare and endangered
species such as the Piping Plover, Florida Scrub-
Jay, and California Least Tern.2
Multiple studies have found that free-roaming
cats reduce wildlife abundance and diversity,
and cause extinctions and dramatic reductions
of native wildlife populations.3
There are more than 80 million pet cats in the
United States according to market research
and a pet food trade association.4 A 1997 na-
tionwide poll showed that only 35 percent are
kept exclusively indoors, leaving the majority of
owned cats free to kill birds and other wildlife
at least some of the time.5 In addition, millions
of stray and feral cats roam our cities, suburbs,
farmlands and natural areas. Abandoned by
their owners or lost (stray), or descendants of
strays and living in the wild (feral), these cats are
victims of human irresponsibility due to aban-
donment, neglect, and failure to spay or neu-
ter pets. No one knows for certain how many
homeless cats there are in the United States, but
estimates range from 60 to 100 million.
After loss of wildlife habitat and fragmentation
due to human development, scientists now list
invasive species, including cats, as the second
most serious threat to bird populations world-
wide.6 It is estimated the annual economic loss
from feral cat predation on birds in the United
States amounts to $17 billion.7 Birds make a
number of significant economic contributions to
the U.S. economy. Birdwatchers spend billions
of dollars on their pasttime, and birds provide
billions more dollars worth of ecosystem servic-
es, such as insect control and plant pollination
that benefits agriculture.
Cats Are Not a Natural Part
of Ecosystems
The domestic cat, Felis catus, is a descendant
of European and African wild cats, and did not
exist in North America until colonists arrived. In
the United States, cats were not abundant un-
til the late 1800s, when they were imported to
help control burgeoning rodent populations as-
sociated with agriculture.
Cats Transmit Disease to Wildlife
Unvaccinated cats can transmit diseases such
as rabies to other cats, native wildlife and hu-
mans. Cats are the domestic animal most fre-
quently reported to be rabid to the Centers for
Disease Control and Prevention.8 Cats are also
suspected of spreading fatal feline diseases to
native wild cats such as mountain lions, endan-
gered Florida panthers, and bobcats, and to
marine mammals, sea otters, and the endang-
erd Hawaiian Monk seal. For more information,
see the fact sheet, The Great Outdoors Is No
Place For Cats at http://www.abcbirds.org/ab-
cprograms/policy/cats/materials/hazards.pdf.
Domestic Cat Predation on
Birds and other Wildlife
Stock.xchng

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Domestic Cat Predation on Birds and Other Wildlife
2
Cat Predation Studies
Extensive studies of the feeding habits of free-roam-
ing domestic cats have been conducted over the
last 55 years in Europe, North America, Australia,
Africa, and on many islands. These studies show
that the number and types of animals killed by cats
vary greatly, depending on the individual cats, the
time of year, and availability of prey. Roughly 60%
to 70% of the animals cats kill are small mammals;
20% to 30% are birds; and up to 10% are amphib-
ians, reptiles, and insects.
Some free-roaming domestic cats kill more than
100 animals each year. One well-fed cat that
roamed a wildlife experiment station was recorded
to have killed more than 1,600 animals (mostly
small mammals) over 18 months.
Birds that nest or feed on the ground, such as Cali-
fornia Quail, are the most susceptible to cat preda-
tion, as are nestlings and fledglings of many other
bird species.9 The U.S. Department of Agriculture
report, Threats to At-Risk Species in America’s Private
Forests, recommends increasing awareness about
negative impacts of roaming cats. According to the
report, “Ground-nesting species and birds that nest
in the open in shrubs or trees are particularly vulner-
able to predation from domestic cats.”
The following are summaries of specific studies:
East Bay Regional Park District, CA: A two-
year study was conducted in two parks with grassland
habitat. One park had no cats,while but more than
25 cats were being fed daily in the other park. There
were almost twice as many birds seen in the park with
no cats as in the park with cats. California Thrasher
and California Quail, both ground-nesting birds,
were seen during surveys in the no-cat area, whereas
they were never seen in the cat area. The research-
ers concluded “Cats at artificially high densities, sus-
tained by supplemental feeding, reduce abundance
of native rodent and bird populations.”10
San Diego, CA: In a study of the relationships
between coyote, mid-sized predators such as cats,
and scrub-dwelling birds, cat owners living along
the rims of canyons collected the prey their cats
brought home. These canyons are isolated pock-
ets of habitat with higher species abundance and
diversity than found elsewhere. On average, each
outdoor cat that hunted returned 24 rodents, 15
birds, and 17 lizards to the residence per year. Birds
were 26.7% of the prey killed by cats.
The researchers estimated that cats surrounding
mid-sized canyons return 840 rodents, 525 birds,
and 595 lizards to residences each year. This lev-
el of predation appears to be unsustainable. The
study also found that in small canyons where the
coyote was absent, there was an increase in mid-
sized predators such as cats, and a drastic decline
in diversity or elimination of scrub-breeding birds.
But in the larger canyons where coyotes were pres-
ent, the scrub-breeding birds were also present.11
England: The Mammal Society conducted a sur-
vey of animals brought home by domestic cats.
During a five-month period in 1997, 964 cats killed
more than 14,000 animals. The mean number of
catches or kills per cat was 16.7, and birds were
24% of the prey. The mean kill rates for belled cats
was 19 and for cats without bells 15. Only 162 rats
were killed by the cats. The researchers concluded,
“Although it is unlikely that cats alone will cause any
species to become endangered in Britain, for those
which are already under pressure for other reasons,
such as thrushes, harvest mice, grass snakes, and
slow worms, cats could become significant.”12
Wichita, Kansas: In a study of cat predation
in an urban area, 83% of the 41 study cats killed
birds. In all but one case, when feathers were found
in scat, the owner was unaware that their cat had
ingested a bird. In fact, the majority of cat owners
reported their cats did not bring prey to them. In-
stead, the owners observed the cats with the bird or
found remains in the house or in other locations.13
Marjorie Gibson

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Domestic Cat Predation on Birds and Other Wildlife
3
Wisconsin: Researchers at the University of Wis-
consin coupled their four-year cat predation study
with data from other studies, and estimated that rural
free-roaming cats kill at least 7.8 million birds per
year in Wisconsin. Suburban and urban cats add to
that toll. In some parts of the state, free-roaming cat
densities reach 114 cats per square mile, outnum-
bering all similar-sized native predators.14
Virginia: Researchers compared a free-roaming
domestic pet cat in a rural area with four urban
cats. The rural cat captured a total of 27 native spe-
cies (eight birds, two amphibians, nine reptiles, and
eight mammals). The four urban cats captured 21
native species (six birds, seven reptiles, and eight
mammals). Between January and November 1990
each cat caught, on average, 26 individual native
animals in the urban area, and 83 in the rural area.
The study did not count prey killed and completely
consumed, prey killed and left elsewhere, prey that
escaped but died later from infection or injury, or
non-native prey.15
Cats on Islands: Because some island bird popu-
lations evolved in the absence of mammalian pred-
ators, they have no defense mechanisms against
them. When cats are introduced or abandoned on
an island, elimination of entire bird populations
can result. Domestic cats are considered primarily
responsible for the extinction of eight island bird
species, including Stephens Island Wren, Chatham
Island Fernbird, and Auckland Island Merganser,
and the eradication of 41 bird species from New
Zealand islands alone. On Marion Island in the
sub-Antarctic Indian Ocean, cats were estimated to
kill 450,000 seabirds annually prior to cat eradica-
tion efforts.16
Cats in Habitat Islands: Cats can have signifi-
cant impacts on local wildlife populations, especial-
ly in habitat “islands” such as suburban and urban
parks, wildlife refuges, and other areas surrounded
by human development. The loss of bird species
from habitat islands is well documented, and nest
predation is an important cause of the decline of
neotropical migrants.17
Cat Predation of Federally-Protected
Wildlife
The Migratory Bird Treaty Act prohibits the hunting,
taking, capturing, or killing of any migratory bird. In
seeming violation of this landmark law, owners of
free-roaming cats permit their pets to kill protected
birds. As noted above, domestic cats are also killing
birds and other wildlife protected under the Endan-
gered Species Act.
The Truth About Cats and Birds:
Well-fed Cats Do Kill Birds. Well-fed cats kill
birds and other wildlife because the hunting instinct
is independent of the urge to eat. In one study, six
cats were presented with a live, small rat while eat-
ing their preferred food. All six cats stopped eating
the food, killed the rat, and then resumed eating
the food.18
Cats With Bells on Their Collars Do Kill
Birds. Studies have shown that bells on collars are
not effective in preventing cats from killing birds or
other wildlife. Birds do not necessarily associate the
sound of a bell with danger, and cats with bells can
learn to silently stalk their prey. Bells offer no protec-
tion for helpless nestlings and fledglings.
Most Birds That Seem to Escape
Do Not Survive
Wildlife rehabilitation centers report that most small
animals injured by cats die. Cats carry bacteria
and viruses in their mouths, some of which can be
Marjorie Gibson

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Domestic Cat Predation on Birds and Other Wildlife
4
transmitted to their victims. Even if treatment is ad-
ministered immediately, only about 20% of victims
survive. A bird that looks perfectly healthy may die
from internal hemorrhaging or injury to vital organs.
A large percentage of patients at wildlife rehabili-
tation centers are cat attack victims and animals
orphaned by cats. In one study at Wildlife Rescue,
Inc. in Palo Alto, California, approximately 25% of
their patients between May and June were native
cat-caught birds, and almost half were fledglings.
Thirty percent of birds and 20% of mammals at the
Lindsay Wildlife Museum in California were caught
by cats.
Cat Colonies Are a Problem for
Birds and Other Wildlife
Domestic cats are solitary animals, but groups of-
ten form around an artificial feeding source, such
as garbage dumps or food specifically put out for
them. These populations can grow very quickly,
can have significant impacts on wildlife popula-
tions, and can cause significant health risks to other
cats, wildlife, and humans. Feeding these cats does
not prevent the predation of birds and other wild-
life. See ABC’s Trap, Neuter, Release brochure at
www.abcbirds.org/cats.
Conclusion
Ultimately, cats are not responsible for killing our
native wildlife—people are. The only way to prevent
domestic cat predation on wildlife is for owners to
keep their cats indoors! Citizens can also oppose
Trap, Neuter, Release programs, which are inhu-
mane and ineffective at reducing cat populations.
See www.abcbirds.org/cats for more information.
ENDNOTES
1
GILL, F. 1995. Ornithology, 2nd ed. W.H. Freeman. New York, NY.
Dauphine N. and Cooper R.J. 2009. Impacts of free-ranging domestic cats
(Felis catus) on birds in the United States: a review of recent research with
conservation and management recommendations. Proceedings of the Fourth
International Partners in Flight Conference: Tundra to Tropics, p 205-219.
2
Soulé, M. E., D. T. Bolger, A. C. Alberts, J. Wright, M. Sorice, and S. Hill.
1988. Reconstructed dynamics of rapid extinctions of chaparral-requiring
birds in urban habitat islands. Conservation Biology 2:75–92.
Donlan, C. J.; Tershy, B. R.; Keitt, B. S.; Wood, B.; Sanchez, J.A.; Wein-
stein. A.; Cross, D.A. and Alguilar, J.L. 2000. Island conservation action
in northwest Mexico. In Browne, D. H.; Chaney, H. and Mitchell, K, (eds).
Proceedings of the Fifth California Islands Symposium, pp. 330-338. Santa
Barbara, California, USA. Santa Barbara Museum of Natural History.
3
Donlan et al. 2000
Veitch, C. R. 2001: The eradication of feral cats (Felis catus) from Little
Barrier Island, New Zealand. New Zealand Journal of Zoology 28: 1-12
Tershey B.R., Donlan C.J., Keitt B.S., Croll D.A., Sánchez J.A., Wood B.,
Hermosillo M.A., Howald G.R., Biavaschi N. 2002. Island conservation in
north-west Mexico: a conservation model integrating research, education
and exotic mammal eradication. Pages 293-300 in C.R. Veitch and M.N.
Clout, eds. Turning the tide: the eradication of invasive species. World Con-
servation Union, Gland, Switzerland.
CALVER, M., S. THOMAS, S. BRADLEY, H. MCCUTCHEON. 2007. Reduc-
ing the rate of predation on wildlife by pet cats: The efficacy and prac-
ticability of collar-mounted pounce protectors. Biological Conservation
137:341–348.
4
2007 U.S. Pet Ownership & Demographics Sourcebook. American Pet
Trade Association Trends and Statistics (http://www.americanpetproducts.
org/press_industrytrends.asp)
5
HUMAN ATTITUDES AND BEHAVIOR REGARDING CATS (www.abcbirds.
org/abcprograms/policy/cats/materials/attitudes.pdf)
6
The American Bird Conservancy Guide to Bird Conservation. Daniel J. Lebbin,
Michael J. Parr, and George H. Fenwick. University of Chicago Press, 2010.
7
Hildreth, A., Vantassal, S., Hygnstrom, S. 2010. Feral Cats and Their Man-
agement. EC 1781. The Board of Regents of the University of Nebraska on
behalf of the University of Nebraska—Lincoln, Extension.
8
Center for Disease Control and Prevention: Rabies (http://www.cdc.gov/
rabies/exposure/animals/domestic.html)
9
Coleman and Temple 1993, Lampila et al. 2005, Sieving and Wilson
1999, Woods et al. 2003.
10 Hawkins, C.C., W.E. Grant, and M.T. Longnecker. 1999. Effect of subsi-
dized house cats on California birds and rodents. Transactions of the West-
ern Section of The Wildlife Society 35:29-33.
11 Crooks, K.R. and M.E. Soule. 1999. Mesopredator release and avifaunal
extinctions in a fragmented system. Nature 400:563-566.
12 The Mammal Society. 1998. Look what the cat’s brought in!
www.abdn.ac.uk/mammal/catkills.
13 Fiore, C. and K. B. Sullivan. Domestic cat (Felis catus) predation of birds in
an urban environment. www.geocities.com/the_srco/Article.html.
14 Coleman, J.S., S.A. Temple, and S.R. Craven. 1997. Cats and Wild-
life: A Conservation Dilemma. 6pp. ww.wisc.edu/extension/catfly3.htm.
In an ongoing, but unpublished, study of cat prey items including stomach
contents, scat analysis, observations of kills, and prey remains, birds were
19.6% of 1,976 prey captured by 78 outdoor cats (Temple, S.A, Univ. of
WI, personal communication, 1/22/04).
15 Mitchell, J. and R.A.Beck. 1992. Free-ranging domestic cat predation on
native vertebrates in rural and urban Virginia. Virginia Journal of Science
43:197-206.
16 Veitch, C.R. 1985. Methods of eradicating feral cats from offshore islands
in New Zealand. ICBP Technical Publication 3: 125-141.
17 Wilcove, D.S. 1985. Nest predation in forest tracts and the decline of mi-
gratory songbirds. Ecology 66: 1211-1214.
18 Adamec, R.E. 1976. The interaction of hunger and preying in the domestic-
cat (Felis catus): an adaptive hierarchy? Behavioral Biology 18: 263-272.