Last month, I had an amazing opportunity to spend a day in the field with a bobcat researcher in the Santa Monica mountains. Laurel Klein is a graduate student at UCLA and is incredibly dedicated to her research. Her research is focused on studying bobcat populations living in urban environments. Urban environments tend to have fragmented natural habitats, which may result in individual bobcats needing access to several fragments in order to survive or find a mate. The National Park Service has been monitoring bobcat populations between Ventura and Los Angeles for more than 15 years; and they have recently seen a decline in bobcat survival rates. Further research has shown that the mortality is often associated with mange infection, which has been linked to the consumption of rats poisoned with anticoagulants. In short, when the bobcats eat poisoned rats, they become more susceptible to the mange parasite. For those that photograph and watch wild bobcats, it is important to know that mange is very treatable, so if you see a sick bobcat, please report it to your nearest wildlife care group or appropriate government agency.
In addition to researching the extent of the mange epizootic (wildlife epidemic), Laurel is also looking at the genetic diversity of the population in her study area. Urban development has broken up formerly contiguous areas of natural habitat, and reduced the number of territories available. An important question is how successfully these urban bobcats are breeding and whether or not their young are able to disperse and establish their own home range. The fragmented habitat may make it less likely that a young bobcat is able to find its own territory and establish one large enough to provide adequate prey and mating opportunities. Two additional hazards of the urban environment include roads (vehicle-strikes are the primary cause of urban bobcat mortality) and competition with coyotes (the most common cause of kitten mortality). While bobcats almost exclusively prey on wildlife, Coyotes are opportunistic omnivores and can make use of additional food sources found in urban areas. This additional food can help increase the numbers of coyotes, which may be detrimental to bobcats.
Understanding urban bobcat population dynamics is important. If the mortality rate of urban bobcats is higher than their rate of reproduction, the population could be stabilized by recruitment from a nearby nonurban population. However, this will only work long-term if the wild population is healthy and produces enough offspring to offset the mortality rate in urban environments. Genetic studies will enable Laurel to determine the health of the overall population and whether or not the urban populations are adequately connected to the intact wild populations.
As a photographer, who has spent a lot of time observing bobcats living in the midst of a suburban neighborhood, I have felt very fortunate to have the opportunity to document their life. However, as a biologist, I wonder about the local bobcat population and why they are inhabiting an area so close to people. I’m very happy that I had the opportunity to spend a day in the field with Laurel and learn more about her research. The following post will talk more about a typical day in the field and how much work is involved.
For more information in urban bobcats, I highly recommend the book – Urban Carnivores