Cats and Birds: A Bad Combination

Outdoor domestic cats are a recognized threat to global biodiversity. Cats have contributed to the extinction of 63 species of birds, mammals, and reptiles in the wild and continue to adversely impact a wide variety of other species, including those at risk of extinction, such as Piping Plover.

The ecological dangers are so critical that the International Union for Conservation of Nature (IUCN) lists domestic cats as one of the world’s worst non-native invasive species.

Cats #1 Threat to Birds

Predation by domestic cats is the number-one direct, human-caused threat to birds in the United States and Canada.

In the United States alone, outdoor cats kill approximately 2.4 billion birds every year. Although this number may seem unbelievable, it represents the combined impact of tens of millions of outdoor cats. Each outdoor cat plays a part.

Instinctive Predators of Wildlife

Even well-fed cats will hunt and kill. Upon reflection, most cat owners will have observed this behavior. When a cat plays with a feather toy or laser, it is practicing predatory behaviors. When these behaviors continue outdoors, the results are deadly for birds and other wildlife.

Unfortunately, the mere presence of cats outdoors is enough to cause significant impacts to birds. Because cats are recognizable predators, their presence near nesting birds has been shown to reduce the health of chicks and decrease nest success.

Cats & Hawaiʻi

Hawaiʻi was originally a paradise for birds. Geographic isolation and the absence of mammalian predators resulted in remarkable biodiversity, including such iconic species as the ʻIʻiwi and Maui Parrotbill.

Unfortunately, the introduction of cats to the Hawaiian Islands in the late 1700s has resulted in the widespread predation of unique native birds and broad environmental contamination affecting people and wildlife alike.

• Cats are indiscriminate predators that kill endangered species such as ʻUaʻu (Hawaiian Petrel), Palila, Nene (Hawaiian Goose), and many other species.
• The presence of outdoor cats in Hawaiʻi also contaminates the environment with the parasite Toxoplasma gondii. Recent deaths of species that do not directly interact with cats, such as Hawaiian monk seals, suggest that neighborhoods, beaches, and waterways may be heavily contaminated.

Our Hawai’i Cats PSA provides an overview of the special issue of cats in our 50^th state. View the video.

Scientific Literature on Cats & Birds

• Blancher 2013: Estimated number of birds killed by house cats (Felis catus) in Canada
• Doherty et al. 2016: Invasive predators and global biodiversity loss
• Loss et al. 2013: The impact of free-ranging domestic cats on wildlife of the United States
• Lowe et al. 2000: 100 of the world’s worst invasive alien species from the Global Invasive Species Database
• Medina et al. 2011: A global review of the impacts of invasive cats on island endangered vertebrates

 Want to live a bird-friendly life? Try these six simple steps!