Abstract:
American birds face an estimated 117 to 157 million exotic predators in the form of free-ranging
domestic cats (Felis catus), which are estimated to kill at least one billion birds every year in the
United States. Cats have contributed to declines and extinctions of birds worldwide and are one of the
most important drivers of global bird extinctions. In this paper, we review recent scientifi c research
on the impacts of free-ranging cats on birds, with an emphasis on threats to migratory landbirds in
the United States. Studies have shown that cats pose threats to many bird populations, including
priority species for conservation, through their predation of adult, nestling, and juvenile birds. Cats
also have impacts on birds through competition with native predators such as raptors, and through
the harboring and transmission of zoonotic and other diseases to birds and other wildlife. In addition
to direct mortality, cats may also cause stress responses in birds due to predation risk that may result
in bird population declines. A substantial increase in public outreach is urgently needed to educate
citizens about the conservation and welfare problems caused and faced by outdoor cats. Effective cat
and wildlife management in this context will also require strengthening and enforcing policies and
laws that control outdoor cats, many of which are already in place.
