Friday, February 1, 2013

Cats eat billions of birds and mammals

Domestic cats kill 1.4 to 3.7 billion birds, and 6.9 to 20.7 billion mammals annually in the United States, according to a paper published this week by Scott Loss, Tom Will and Pete Marra, in the journal Nature Communications.  

The report points out that the large majority of these deaths are caused by cats without owners.  Reading this reminded me of  an experience I had while conducting field work for my Masters Thesis in the Grand River Forests between Cambridge and Paris, Ontario.  

I was conducting breeding bird surveys deep in the forest, probably a couple of kilometres from the nearest residence, and twice spotted cats perched high above the ground on tree branches, watching me like a bobcat would.   They were likely farm cats, or abandoned cats (it's not uncommon for people to dump an unwanted cat in the country) that had essentially become 'wild.'  

I also have a vivid childhood memory of my friend's cat catching a Barn Swallow.  Standing by his swimming pool, I watched adult swallows zipping through the air in pursuit of insects to feed their brood living in their garden shed.  I noticed the swallows changed their behaviour and started swooping low over something on the ground, which turned out to be my friend's cat. 

The cat was laying on its back, face up, watching the spectacle, as the swallows swooped closer and closer.  The cat flattened itself, compressing its body against the ground, as the swallows swooped closer, only a few metres from the entrance to the shed, and their nest.  Then suddenly, with lightning speed, the cat shot up a paw, batted a swallow from the air, and proceeded to grab it in its mouth and run away.  One less parent to feed the brood!   I stood there dumbfounded at what I had just witnessed - confused by my feelings of empathy for these graceful birds, and awestruck by the incredible hunting ability of the cat.  

Reading the recent report about cats' impact on wildlife is a sharp reminder that the problem has not gone away - but perhaps has gotten much worse.  We need to, and can do, more in our urban environments and rural environments to reduce our impacts on wildlife. 

By and large, cats and birds simply do not get along. The most effective way to protect birds and other wildlife from cats is to keep your cat indoors.

Keeping cats indoors not only helps prevent predation of birds and wildlife; it also reduces the spread of disease, unwanted reproduction, and prevents the cat from being struck by cars.

If you must allow your cat to roam free, be sure to locate bird feeders in open areas where cats cannot ambush birds. Place guard fencing or other obstacles at the base of the feeder to make it harder for cats to climb feeders. Do the same around trees where you have nesting birds.

Other ways to prevent cats preying on birds:

  • Keep only as many pet cats as you can feed and care for. Make sure all your pets are spayed or neutered to prevent the birth of unwanted animals. 
  • If you live on a farm, keep only as many free-roaming cats as you need to control rodents.
  • Remove garbage, pet food dishes and other sources of food that may attract stray cats to your yard
  • If you have an unwanted cat, do not abandon it in a rural area (or anywhere for that matter). Try to find a new owner or drop it off at a shelter.

Finally, two relatively ineffective methods include:

  • Putting bells on cats. Birds rarely respond in time to a bell, and often don’t even understand the significance of the sound.
  • Declawing cats. Even a declawed cat is a skilled predator, and some owners consider the practice to be cruel to the cat.
While I'm offering advice, might I suggest you check out our 12 tips to help birds and wildlife thrive in your backyard; think of these ideas as you prepare to Welcome Back Birds, the Canadian celebration of International Migratory Bird Day this May. 


Queenie said...

Let's not fail to mention the FACT that human activity is responsible fo far more bird deaths annually. Habitat destruction, urban sprawl, tree logging, pesticide use, tall buidings has been shown by research to cause more deaths than that caused by any other species. We need to take responsibilty also instead of finding a scapegoat to villify, whom can't defend themselves.

Anonymous said...

Breeding and keeping domestic cats IS a human activity! Also,from the source study, free ranging cats are likely the "...single greatest source of anthropogenic mortality for US birds and mammals. "

prairiegal said...

As usual humans are always putting the blame on anything but themselves. Blame the stupid ignorant human being who treat cats like disposable garbage. Human animals are the cause of the problem but other animals always suffer the consequences.

Lynette said...

Yes, the reason there are cats is because we have introduced them to the environment, whether this is as our domestic pet cats, or the feral cats. And, yes, we are responsible. And, yes, I love cats.

However, what is significant about this new research, is the number killed. Up to 3.7 billion is an astronomical number of birds (as well as mammals and lizards) that the cats (both owned and feral) are killing each year in the US alone. This is a huge problem. Much more than was previously thought, and on par with other human interferences (buildings, habitat destruction, etc). And, I agree, the problem of bird loss has to be tackled on all fronts.
Moving forward, in order to help the birds, something has to be done with the feral cat population. CNR programs are not enough. CNR = catch/neuter/release. The cats are still alive to kill the birds, etc.

Matt Robinson said...

This comment is addressed to Queenie.

I found this article to be pretty informative, fair, and unbiased.

The bloger's article is about domestic cat predation, not about anthropogenic influences on avian populations. Although I can't speak for the author, it seems like he's just pointing out a very relevant issue concerning unnecessary bird mortality and some suggestions for cat owners to help reduce some of the wildlife that gets killed by cats.

Perhaps he doesn't point out that humans are responsible for habitat destruction, urban sprawl, ect., becuase that's not what the article is about.

So maybe you should stick to the issue.