This week takes me to Chicago, where I am at the International Urban Wildlife Conference. Here the talks are all focused on the biology of unnatural ecosystems, cities and their surrounding sprawl. When you think of urban wildlife, likely pigeons, rats and raccoons, come to mind, but you be surprised to learn the rich biodiversity that cities have. This is what these scientists study (but also the pigeons, rats, and raccoons). Below I highlight some of the themes from this year’s conference.
To Feed or Not to Feed?
On the opening morning of the conference, two of the keynote speakers, Jim Sterba and John Marzluff talked about the direct feeding wildlife by people with some pretty contrasting views on the outcome. Sterba, author of Nature Wars, accredited wildlife as our new “pet.” As our regular pets have now been upgraded to near children status (companion animals, members of the family, and “fur-babies”), we are starting to pamper the wildlife in our backyard in similar ways. Sterba showed a photo of “Beak Bistro” birdseed as an example of we are starting to spend big bucks on treating our new wild companions. He cautioned that this approach however changes the human-wildlife dynamic from being something we fear to something we want to cuddle and help. In fact, most people say they feed birds and other wildlife to “help” the animals.
John Marzluff, on the other hand, thought feeding wildlife was good because it allows for people to directly experience and care for nature first hand. He felt that these first-hand experiences with animals as common (and even invasive) as the Canada Geese or gray squirrels in our backyards will lend to concern for the endangered Baird’s tapir that lives in Central American rainforests, exceedingly far from our backyards, but in desperate need of conservation help. Marzluff, an ornithologist, is used to the idea of feeding partly because so many people feed birds from common backyard feeders, and we as a society are okay, even proud of doin this (including scientists). But a different message is typically sent for the other critters – that feeding them is bad. The speakers were directly asked this question, and while all admitted that feeding bears is definitely bad, as bears become bolder and will break into trash cans, cars, and houses to get human food (“a fed bear is a dead bear”), all did not think that the medium to small sized mammals were so bad. But when feeding these smaller mammals, how do we prevent the larger ones from coming? One speaker showed a video of a man that puts out piles of dog food for coyotes each day and a woman that feeds some 60+ raccoons that live directly under her house. Regardless of your position on the issue, humans are adding a massive amount of food to the urban ecosystem, both directly and indirectly. The U.S. Fish and Wildlife Service estimates that over 50 million people directly feed wildlife and that over 36 million tons of food is thrown out each year, which wildlife can access depending on how secure trash is. What is definitely known, is that we have very little idea on how this large amount of food added to the ecosystem is the animals and other biota living in it.
Some Species are City Slickers
Coyotes in Chicago, bobcats in Dallas, and pumas in SoCal: you may have heard of theses urban-adapted species, but you probably don’t know how truly adapted they are. Not only are coyotes living in Chicago, but are thriving in Chicago. These animals are not sick and mangy, but healthy, strong and with large litters (one was 11 pups!). They are not just living in the green spaces within the city center, but occupying completely developed landscapes. For example, I-90 is a corridor for one of the city’s packs.
Bobcats, which are an elusive species in the Raleigh area where I live, are rarely seen close to areas of human development, let alone city centers. On our camera traps run in the triangle area, we only have a couple of bobcat photos with one in a nature preserve within the city limits and the others in more exurban/rural habitat. In the study done in Dallas, the researcher caught bobcats during the day (to be fitted with GPS-tracking collars); one was near a large apartment complex with construction going on. One bobcat is partly diurnal and seemingly bold, having developed a reputation on the local bike trail. Being seen during the daytime, he quickly became a favorite for bicyclists to spot.
Finally, probably the most famous case of an urban carnivore in the US, is the mountain lion population in southern California, with one especially famous individual P22, living right in Griffith Park. This male has had his photo captured right in front of the Hollywood side, exemplifying the contrast between his super wild being and new urban lifestyle. Even though P22 lives in a small park, and this park is visited by millions of people (roughly the same amount as Yellowstone, but significantly smaller in size), he is very rarely seen, even by expert scientists. The southern California lions definitely have challenges living in this highly urban environment. For one, many get killed by vehicles. This is especially problematic as the population grows. Male kittens that mature eventually have to disperse to establish new territories. If a male is already there, the new male will be killed. Finding new, empty territories means crossing more major highways, increasing the risk to get hit by cars. Luckily, and due to the popularity of P22, residents in California are rallying behind their mountain lions and are in support of corridors to help the lions cross the road. Before these corridors are being built, scientists have already built large fences around high-traffic highways to prevent mountain lions from crossing at dangerous points, but funnel them into safer crossings like bridge underpasses.
Encroaching on them? Or Encroaching on Us?
Long have we heard that people and development are bad for wildlife. Habitat destruction is one major causes of species decline and extirpations. One speaker presented a map of their metro area from the 70s until now. Each decade seemed to add an exponentially to sprawl. But for some of the areas, especially those mentioned above, people have long been established there, like hundreds of years. From the establishment of Chicago as a large city, coyotes have never lived in that urban habitat. There are also coyotes in the boroughs of New York City. Bears in Colorado on the other hand, use both wild and urban habitats. They move into the metro areas during bad food years to scavenge trash and other human refuse. These and other urban adapter species are recolonizing habitat that has been seemingly unavailable to them and from our perspective, impossible to live in. How? This is probably the most fascinating question for urban wildlife. What behavioral, genetic, or physiological adaptations allow for some individuals and populations to navigate, penetrate, and thrive in these highly urban ecosystems? Right now, no one knows.
So the next time you’re out walking, whether it’s a street lined with skyscrapers or a neighborhood with mowed lawns and McMansions, take a closer look around you. This too is an ecosystem thriving with life, the urban ecosystem. Perhaps the least studied of all ecosystems, despite it being it right under our nose.