Research on carnivores in SMMNRA has been ongoing since 1996. During this time, a number of different methods have been employed to learn more about these animals!
Research Method 1: Trapping
Trapping is a frequently utilized tool to gather samples and information about local wildlife populations. All trapping requires permits through local state agencies and oversight from animal ethics committees. We conduct trapping and capture events humanely with special protocols enforced to reduce stress on animals while captured and handled.
Why trap? In order to collect blood and tissue samples, and to place tracking devices on the animals, we must capture the animals. This involves trapping. Permits to do so are required through the State of California, and for UCLA research, we must also have oversight by an animal ethics committee as well. Trapping an animal handling is something we take serious in order to ensure the safety of our study animals and our biologists on the ground handling the animals. We each go through a lot of training, and have strict protocols we follow to ensure everyone's safety.
What kind of traps? We use cage traps to capture our bobcats and for mountain lions we use a mixture of cages and snares. The cage traps are quite cumbersome and weigh almost 40 pounds, and a sight to see us hauling them through the chapparel. We set the traps in areas that we know these wild cats travel. One important secret to trapping success is location, location, location! Don't expect to set a trap off a wild cat travel route and to catch a wild cat anytime soon.
How do we know where to set traps? How do we find travel routes for these wild animals? Lot's of walking! And for maximum efficiency, lot's of time looking at maps too. The maps which show topographical features can potentially show areas where animals might naturally be "funneled" into a general area. For instance, in mountainous or hilly areas, where several ridges intersect could be a great area to go look for sign. Or where several dry creek beds intersect is also a great place to set a trap. By using satellite images of an area, we can search for obvious animal trails through the dense brush. These trails can sometimes be so "strong" and well-used by animals that we can actually see the trails on google earth! Once we see good spots on maps to investigate, we can actually physically go to that area and start looking for animal sign (see bobcat page for more information). Sign we are particularly interested in and the easiest to find include scat and scrapes, and sometimes tracks.
When do we trap and how frequently do we check traps? We trap only during certain times of the year when we know the female bobcats are not tending to kittens. From mid-February to early June we don't trap because this is kitten season for the bobcats. For mountain lions, we trap year round since they do not have a set breeding season and since females do not have litters of kittens every year. Once a trap is set, we check the traps twice per day, in the morning and afternoon. Given the frequency of capturing bobcats or mountain lions (not very frequent!), we leave traps open 24/7. So, we are out checking traps every day, twice a day, during our trapping season. Sometimes we need a break and close traps for a short period of time, but then we are back at it again in order to try to get as many animals as possible during each season. Further, you might have to wait weeks before a cat will walk by a trap, and so if you close them frequently, you can easily miss your single opportunity to get an individual.
What do we put in the traps and what are the feathers that are seen in the pictures of trapped bobcats? Cats are visual predators, and bobcats are no exception. To entice them near and into a trap, we use visual lures. These lures can vary depending on how visible we want the trap. Also, we consider the effectiveness of visual lures interms of both short- and long- distances. For instance, bones placed on the ground in front of traps will only catch the eye of an animal already near the trap. On the other hand, CDs and shiny things hanging from a tree above a trap will catch the eye of an animal from a further distance. One of the items we put in front of and within the trap to make sure the bobcat's attention is really drawn to the trap are lots of feathers! We purchase feather pillows (not down pillows, the feathers are too fine) and pull feathers out of the pillows to put inside the trap. Thus, the feathers you see in our photos are not from birds that the bobcats themselves have eaten while in the trap. Inside the traps, we experiment with a variety of lures and baits, including roadkill we find (dead deer and rabbits are great finds for us), decoy rabbits and birds, wings, feathers, and scent lures. There's actually a lot of tricks to experiment with when trying to catch a wild cat.
Research Method 2: Scat Surveys For Diet Analysis
A common animal sign that we find when walking in an animal's natural habitat are their fecal material, or scat. Each species of animal can have unique characteristics to their scat, and they certainly have uique genetic markers that can be analyzed from the scat. By identifying what animal scats are found in a region, we can do a survey of species present. By examining what we find in the scat, we can identify what those species are eating! There are many other things you can do with scat- for instance, if preserved properly when it is found fresh, you can also measure certain hormones that measure stress levels of the individuals. You can also identify what internal parasites individuals have from relatively fresh scat.
You can typically find hair and bones in the scat of carnivores from their animal prey. For canid (dog family) carnivores (coyotes and foxes), their diets consists also of plant material including fruits, so you will also seeds in their scats. For strict carnivores like bobcats, it is rare to find material other than hair and bones. By picking the bones and hair out of the scat of many bobcats in a single area, you can not only identify what their common prey items are, but also which are preferred prey items of the bobcats!
National Park Service biologists conducted scat surveys in order to determine the common food items for bobcats, coyotes, and grey foxes in certain parts of the Santa Monica Mountains. In order to do this, regularly walked certain fire roads, walking the same trails and distance on those trails once a month for a year. They collected coyote, fox, and bobcat scat along those predetermined trails. They noted the number of scats they collected for each species. They then dissected those scats and determined what food items were in them.
Results of this study were published:
Fedriani, J.M., T. K. Fuller, R.M. Sauvajot, and E. C. York. 2000. Competition and intraguild predation among three sympatric carnivores. Oecologia, 125: 258-270.
Research Method 3: Disease Surveys
Disease surveys are performed on the blood samples we collect from the animals we capture. We typically look for evidence of exposure to diseases rather than the specific disease itself. In fact, it is very rare to find a wild cat in our study area displaying signs of disease. To test for exposure, we examine serum from the blood for the antibodies to different feline diseases. Antibodies are developed by the animal in response to exposure to a disease. This work is underway, but preliminary findings suggest no issues with diseases that are out of the ordinary compared to other populations of bobcats and mountain lions that have previously been studied.
More recently, we've also been collecting fecal samples to examine these samples for the eggs of internal parasites. Also, we've been collecting skin scraping samples to look for the ectoparasitic mange mites that have had such an impact on our local bobcat populations. Presently, an undergraduate student, Cindy Hong, is helping us look at all the fecal samples we've collected to find what internal parasites our bobcats are carrying. Collaborators at Colorado State University are helping us with our disease surveys. And graduate student, Laurel Klein, in collaboration with Janet Foley's lab at UC Davis is analyzing the results of the skin scrapings in one effort to determine how prevalent the mange mite is in our bobcat and mountain lion population.
Research Method 4: Genetic Analysis
Genetic work for bobcats has been exclusively completed in the laboratory of Robert K. Wayne at UCLA (see www.eeb.ucla.edu/Faculty/Wayne/ for more information) and genetic analysis on mountain lions is done at both the Wayne Lab and at the Ernest Lab at UC Davis. When we capture bobcats and mountain lions, we take tissue samples from individuals to use for genetic analysis. We have also collected scat (fecal matter) for genetic studies. Finding mountain lion scat is rare, though, so this method of sample collection is better for animals, like bobcats, that leave their scat in obvious places. When fresh, scat collection can be a useful, noninvasive sample used to learn more about wild animal populations.
So far, we have used genetic analysis to understand population level factors for the bobcats and the mountain lions. There are many different genetic approaches available now and that are continuing to develop and so far, we've used only a few simple analyses to learn more about our animals. However, we do have a large-scale genetics project underway to study the bobcat and mountain lion immune-related (Major Histocompatibility Complex) genes in the Santa Monica Mountains. We also collected samples we hope to use for future gene-expression studies.
For the work we've done so far, we have used genetic studies to understand relationships between individuals (ie., we have constructed a mountain lion pedigree and are working on a bobcat pedigree), populations separated by roads, and as a simple proxy of population health for both bobcats and mountain lions. Some of these data were published in Riley et al., 2003 and Riley et al., 2006. What we have so far discovered is that the 101-freeway is a significan barrier to movement for bobcats and coyotes. There is much greater distance between populations separated by the 101-freeway than by populations on the same side of the freeway spearated by significantly greater distances than those populations separated by the 101. In other words, the 101-freeway is a greater barrier than geographic distance. We have also learned from examination of microsatellite data that mountain lions are very monomorphic (lacking variation at these microsatellite data) at the loci we genotyped. This can make resolving relationships between individual mountain lions challenging, and also makes us wonder if this monomorphism extends to genes where variation is important (like the genes related to immune function)!
Research Method 5: Health Assessments
Since 2008, when we've captured a bobcat or mountain lion, we have performed a complete blood
count (CBCs), blood chemistry analysis, urinalysis and collected a fecal sample for a fecal parasitie float. These items are all things your vet would do for your pet if you suspected something wrong with it, or just to monitor it's health. CBCs count both white and red blood cells, and can be indicative of , for example, immune response of the animal (ie., if it is fighting infection and thus with elevated white blood cells) or anemic, or if all the values appear normal, we expect the animal to be in a generally healthy state. The blood chemistry and urine analysis can be indicative of organ function since we aquire information from these values, for example, about the liver, kidney, and electrolyte balance. We have been gathering these data on our bobcats and mountain lions accross our study area, and so in the case when we capture a sick animal, we have a population's worth of data to compare our sick animal's values to. Also, as it turns out, the CBC and blood chemistry values are not much different than the domestic cat's values.
So far, we have notice anomolies in the data for bobcats that have mange and anticoagulant exposure. We are presently working on publishing a paper with these data.
Research Method 6: Anticoagulant Surveys
Anticoagulant rat poison surveys are a big part of our present study. We work with collaborators at California Animal and Health Food Safety Laboratory (CAHFS) in Davis, California for this portion of our study. Unfortunately, we have thus far had little success in testing our bobcats and mountain lions for exposure with blood, and have been able to rely only on the liver. Anticoagulant compounds accumulate in the liver, and with an elimination half life on the order of months, testing liver for anticoagulant residues can prove a method of understanding the history of exposure for each individual. So far, we've tested only those animals that die in the study area, collecting their liver shortly after death to do so. We are hopeful that we can test blood from animals captured in the study area soon since CAHFS has recently made advances on the assay we are using for this test.
Research Method 7: Radio-Telemetry
Radio-telemetry uses radio signals to locate animals and follow their movements. Radio-telemetry involves two components - a transmitter and a receiver. The transmitter is attached to a collar worn by an animal, in our case, a bobcat or a mountain lion. The transmitters emit a signal on a specific frequency that can be monitored by a receiver and each bobcat is given a unique frequency. The receiver is a small radio-like device fitted with a special directional antenna. The antenna receives the signal and inputs it into the receiver. The receiver interprets the signal and calculates the strength, measured in audible 'beeps'. Strong signal strength indicates the signal is directly ahead and is expressed by loud beeps. Sweeping the antenna in a 360-degree arc will aid in finding the strongest signal (i.e., the loudest beeps). Once the direction is determined, using a compass, a bearing can be made (a bearing is the angle from north, where north is 0 degrees, east is 90 degrees, south is 180 degrees, etc.). A second and, sometimes, a third bearing from a different location is usually made within a short period of time from the first bearing measurement. Using the intersections of the bearings, as well as, the location of where the bearings were made (i.e., by GPS), the animal's location can then be determined.