Cats And Coyotes Divvy Up The Chicago Suburbs

coyoteI’ve been to Chicago and the surrounding area plenty of times, but I never thought to look for coyotes. I hadn’t realized that the animals have been expanding their territory over the last several hundred years, and they can now be found in many U.S. and Canadian cities, including Chicago. In many of these areas, coyotes are now the largest carnivores, at the top of the food web. And that might be affecting some of the animals we are more familiar with.

Urban coyotes have a varied diet, consisting mostly of small rodents, white-tailed deer, fruit (carnivores aren’t strictly meat eaters), bunnies and birds. They also eat a small number of cats, which led a group of scientists who are studying urban coyotes in the Chicago area to look into how coyotes and feral cats interact in the city’s suburbs. The results of their study appear in PLOS ONE.

feralcatBetween February 2008 and September 2009, the researchers captured 43 cats in eight sites in the suburbs west of Chicago. They then took blood samples from the cats and fitted 39 with radiocollars (two cats were thought to be pets, one was too small for the collar, and one was so sick it was euthanized). Getting good data from the cats was difficult: A fifth of the cats died during the study period, a quarter were adopted, 13 percent had collars that didn’t last until the end of the study, 10 percent were never heard from again, and, in what is the most mysterious statement in the study, 23 percent “were removed from the system by cat advocates opposed to our research.” Despite the difficulties, however, the researchers were able to get good tracking data for a number of kitties, enough to map out several cats’ home ranges and plot them against the ranges of coyotes in the urban coyote project.

The cats and coyotes, the researchers found, did overlap a bit in their travels, but for the most part, cats stuck to areas around homes and buildings. The coyotes, in contrast, preferred natural habitats away from human development. “Coyotes in our system appear to inhibit cat use of the natural habitat fragments through a combination of predation and cat avoidance of coyote activity,” the researchers conclude. “It is clear the two species are largely separated across the metropolitan area.”

This is only a small study, but the team speculates that coyotes may be controlling the feral cat population throughout the Chicago area, keeping the cats out of the fragments of natural habitat that dot the suburbs. If the pattern holds in other areas, then in regions where coyotes can be found, the ecological impacts of cats (that is, the cats’ killing of birds and other native wildlife) might be overestimated. Cats have gained a reputation for being evil murderers that devastate wildlife, but we’re finding that the story is far more complicated. And its one that needs to be better elucidated.

Images courtesy of flickr users John Picken (Chicago coyote, top) and cats marcoff (Chicago feral cat, bottom)

The Chickens of Kauai


If there’s a soundtrack to the Hawaiian island of Kauai, it’s not waves or the songs of a native bird or even hula music — it’s the crow of the cock. Everywhere I’ve been on Kauai, from the beach to the town to the mountains, there have been chickens.

The chicken population on the island exploded more than 20 years ago, after Hurricane Iniki, which devastated several Hawaiian islands. On Kauai, one of the lesser effects was that the storm blew apart chicken coops — possibly many housing fighting chickens — and released the birds into the wild. It’s not all that surprising that the birds then thrived because their wild ancestor, the red jungle fowl, lived at similar latitudes in Southeast Asia.

(You might think that all those chickens would be a great source of food for the local people, but I’ve been told that the birds are hard to catch. Chickens can see and keep track of four things at once — up and down and with each eye — so it’s hard to sneak up on one. Plus, the meat is tough. I suggested to one local that he try coq au vin — the traditional French method of cooking an old bird — but he looked at me like I was nuts. I still maintain, though, that even if it’s not a local dish, cooking a chicken in lots of wine, and maybe some garlic, would sure be tasty.)

Chickens are just one of the non-native species that have spread across Kauai, and one of the less destructive ones. I visited with Diane Ragone, head of the Breadfruit Institute, this week, and she noted that while most people look at this island and see nothing but lush green mountainsides, she sees lands bare of native plants. And then there’s all the invasive animals. I found a couple of adorable young feral cats at the end of the road (literally) on the North Shore of the island and winced when a woman started feeding them. I don’t want kitties to die, but they are a huge problem on islands like this one because they kill native birds. And here there are some spectacular birds, such as Laysan albatrosses and red-footed boobies. Feral pigs now roam the island, causing all sorts of damage. There’s even deer that have been purposely released so people can hunt them. There’s a flock of parrots that derive from someone’s lost pets.

One of the things that has struck me since I’ve been here is how most tourists will never realize that the island has changed dramatically in the last couple of hundred years, since the first Europeans arrived and began introducing all these non-native species. Kauai is beautiful now and truly lives up to its nickname as the “Garden Island,” but what must it have looked like before all of this changed?

Photo by the author

Human Presence Takes A Toll On Galapagos Sea Lions

sea_lionWhen you think about the Galapagos Islands, there are a few things that come to mind. There’s Charles Darwin, of course, and the studies he made there that contributed to his development of the idea of evolution. And the amazing wildlife, including tortoises and iguanas and a whole host of birds. What you don’t think of are things like pollution and invasive species, but these are growing problems, especially in the areas inhabited by humans.

Some islands are still pristine, though, and that gave a group of biologists, led by the Zoological Society of London, a chance to see how one species, the Galapagos sea lion, is affected by the presence of humans. The researchers compared immune activity and body condition of two populations, one in Bahia Paraiso on the undeveloped island of Santa Fe and another that lives in the center of the rapidly growing town of Puerto Bazquierizo Moreno on San Cristobal. The study was published last week in PLOS One.

None of the animals appeared to have signs that they were sick, but those that lived in town had more active immune systems. And among the pups in that colony, those that had higher levels of antibodies had thinner skinfolds and were skinnier.

“A tell-tale sign of an unhealthy sea lion is a thinner than normal layer of blubber, which is what we saw in the sea lions on San Cristobal,” study coauthor Paddy Brock of the ZSL said in a statement. The more active immune systems could indicate “a threat of infectious disease, which could mean human activity is increasing the chance of potentially dangerous diseases emerging in the Galapagos sea lion,” Brock said.

Puerto Bazquierizo Moreno does not seem like it would be a great place to be a sea lion. The bay is home to more than 200 boats and filled with fecal contamination from the vessels and sewage from the town. And the land has a bunch of animal threats, including people’s pets, feral cats and rats. If these factors are impairing the immune systems of the sea lions that live in the area, the impaired immunity could reduce the marine mammals’ ability to hunt, the researchers say.

And the Galapagos sea lions don’t need anything else to hamper their survival. The species was listed as endangered by the IUCN after its already-small population declined by more than 50 percent in the last three decades. The sea lions, which are a bit smaller than the more familiar California species, are not afraid of humans and like to hang out on rocky shorelines and sandy beaches (above). That can put them in direct contact with the human population and make them vulnerable to threats like uncontrolled dogs that will kill sea lion pups.

These sea lions have figured out ways to deal with some threats — they’ve been known to mob Galapagos sharks that approach their rookeries — but they haven’t yet evolved to deal with the ones humans have brought to them. Their immune systems didn’t evolve to exist in a sewage-filled, pet-dominated environment. And it appears that’s put them at even more risk of disappearing from the planet.

Image credit: ZSL_Paddy Brock, via EurekAlert


Dear Nature Lover, My Cat Isn’t Your Problem


Thousands of years ago, cats and humans struck a deal. We’d give kitties a home as long as they took care of our vermin. The cats don’t always hold up their end of the bargain — my own, for example, has done nothing about my current mouse situation — but humans haven’t done much better. And now we have a huge problem.

A paper published today in Nature Communications documented a kitty kill tally that’s pretty scary. In the U.S., cats kill as many as 3.7 billion birds and 20.7 billion mammals every year. Culturing Science calls them “ruthless killers.”

They’re right, of course. That’s why we inviting cats into our homes.

But a closer look at the study shows that it’s not cats like mine that are the problem. My kitty never goes outside. But even owned cats that go outside aren’t the worst killers. Unowned, feral cats accounted for 89 percent of the mortality.

And the fault with the feral population lies with us humans. People don’t get their pets fixed. They let them roam free or, worse, abandon them. And well-meaning people feed feral cat populations, letting the animals survive and kill more wildlife.

So what’s to be done? It has to start with a serious conversation about how we care for cats. We need to get more people to spay and neuter their animals, and encourage them to not let their animals outside. (Really, house kitties are happy.) And we have to figure out what to do with feral cats. Trap-neuter-release programs appear humane, but it’s having devastating affects on the natural world.

Ideally, I would gather up all the feral kitties in the world, get them fixed, and let them live out their days in huge barns. That’s probably not practical, but at least it’s an idea.

Image credit: Flickr user Janesdead