House cats love to hunt birds. Here's why that has biologists and conservationists worried

A study published this week in the journal Nature Communications found that free-ranging domestic and feral cats eat more than 2,000 different species in the wild.

That has ecologists and biologists seriously worried.

"It's been known for a long time that cats create a real problem for biodiversity — that's not new," said Catrin Einhorn, a reporter for The New York Times. "But what these researchers did is they sort of exhaustively went through all the records they could find to document all the different species that cats had been found to eat in the world, whether they hunted them or they scavenge them."

Among the most surprising finds? Cats have eaten camel, cow, and endangered green sea turtles. Cats have an impressive ability to hunt, but Einhorn said researchers believe cats ate the scavenged remains of those animals. Researchers also documented cats' impressive ability to hunt, scavenge, and eat insects, reptiles, birds, amphibians and other mammals.

People don't want to think of our beloved pet cats as an invasive species, but Einhorn said that research indicates they have the potential to cause "devastation" to an ecosystem.

"In the United States every year alone, [cats] were estimated to kill a median 2.4 billion birds," Einhorn said. "And it's not like that's not having a consequence, because we know that birds in North America are doing really badly and have gone down by almost 30% [in population] since 1970."

Other factors are driving this decline in bird population as well, Einhorn added, but cats do play a role.

So where does that leave cat owners?

After talking with conservationists, Einhorn said owners should weigh the ecological consequences of letting their cats go outside and potentially hunt.

"Most conservationists would say that you should absolutely not let your cat outside — that it's just an irresponsible thing to do," Einhorn said.

However - there can be an ecological upside to indoor cats. Rather than putting out rat poison to handle your rodent issue - let your cat exercise their penchant to hunt. You'll avoid having other animals - like foxes and raptors - eat the poisoned rodents.

Listen to the full interview with Catrin Einhorn by clicking the play button at the top of this story.