We usually think of birds as soaring across the sky way over our heads. But many species of birds spend more time on or near the ground than you might think, and that’s one of the main reasons they’re vulnerable to cats.

Ground-feeders

Ground-feeding birds include the American Robin (pictured), a familiar backyard bird, regularly seen on the ground hunting for worms. They also nest in backyard trees, which are often easily accessible to outdoor cats. Common grackles, cardinals, and towhees are other examples of ground-feeding birds.

Ground-nesters

Other birds actually build their nests on the ground, or sometimes even in a nearby flowerpot. Their nests are often camouflaged, but cats can find them using their great sense of hearing. Ground nesting birds include the Dark-eyed Junco Mourning Doves, Common Nighthawk  (threatened), and Killdeer (on gravel, including roadsides).

Shrub Nesters

Still other species of birds, such as the Northern Cardinal  build nests low to the ground in small trees or shrubs. Unfortunately, cats often go to the same kinds of places, they are agile climbers, and their coats provide camouflage, making it hard for the birds to see them. Other bird species that may nest near the ground include various sparrows and warblers.

There are also kinds of birds that have gotten used to making their nests on human structures, especially in barns or under the edge of a roof. Because these species are found close to humans, they are also close to our cats, which puts them at risk. This group includes Barn Swallows (Threatened) and Purple Martins.

Nestlings and Fledglings

Nestlings are baby birds still in the nest. They are vulnerable to cats and other predators because they can’t yet get out of the nest. Not only that, but their parents will defend them from harm. Since even the fiercest songbird parent is no match for a cat, this often means nestlings go hungry because there’s only one parent to find food for them, and are sometimes orphaned.

Fledglings are birds that have only just left the nest. The parents may or may not still be feeding them. Fledglings are vulnerable to cats because they aren’t yet very good at flying, so they can’t get away.

According to a new study from the UK, outdoor cats have an effect on birds even if the cat is not actually hunting. The research, published in the Journal of Applied Ecology, was led by Karl Evans at the University of Sheffield. The report concludes that even a brief appearance of a cat near a bird nest leads to behavioural changes in parent birds that lead to a roughly 1/3 reduction in the amount of food brought to nestlings. Additionally, the natural response of parent birds to the appearance of predators — alarm-calling and nest-defense — dramatically increases bird nest predation by other animals who’ve been alerted to the nest.

Lastly, birds have papery thin skin, and even the slightest nick from a cat’s claw or tooth can cause a fatal infection. The survival rate for birds injured by cats is very low compared to other types of injuries. Infection is a big issue, but so is shock – not surprisingly, it’s very stressful for a bird to be attacked by a cat, and stress and shock inhibit the birds’ ability to recover from a wound or subsequent infection. (Cat bites and scratches can be dangerous for people too – always be sure to wash any wound carefully and monitor it for infection.)

It is completely natural for cats to hunt, and cats aren’t to blame for doing what comes naturally. But they aren’t native to our ecosystems, they’re pets, and so are part of humane society. As humans, we owe both cats and birds protection, and it’s important to take care to keep them apart. The best way to keep birds safe from your cat is the same way to protect your cat from wildlife that might hunt or fight with your cat: keep your cat from roaming outdoors. Cats can be prey as well as predators, and pets and wildlife should always be kept separate, for the benefit of both.

If you’d like to read about the reverse scenario, why cats are vulnerable to wildlife, click here.