Derek Broman has a passion for wild carnivores. You can hear it when he talks about bobcats. He studied bobcats in Iowa, Connecticut and New Hampshire for his master’s degree.
In Texas just 15 months, Broman is heading up a Texas Parks and Wildlife Department urban bobcat study in conjunction with Utah State University, the National Wildlife Research Center and the Welder Wildlife Foundation.
The study area covers 49,000 acres of urban and suburban sprawl — parts of Arlington, Hurst and Fort Worth. According to the 2010 census, the study area had 229,674 people and 103,475 housing units. The number of bobcats is yet to be determined.
Bobcats are successful in dwindling habitat because of their secretive, nonconfrontational nature, Broman said. Bobcats are, by far, the most common wild cats in North America, yet few people have ever seen one.
“Little is known about bobcats in urban areas throughout their entire North American range,” Broman said. “D-FW was selected as the urban study site because of the high number of bobcat sightings and because both D-FW urban biologists, Brett Johnson and me, have backgrounds in carnivore research and ecology.”
Live trapping started in January and ended in April. Fourteen bobcats were trapped in the north central portion of the study area, and 10 were large enough to equip with Global Positioning System collars that weigh about half a pound. The collars record positions on a regular basis, approximately 3,000 waypoints a year.
The collars are designed to drop off the animals after about a year. The collars will send a signal, allowing them to be retrieved and the data downloaded, revealing some of the mysteries of how bobcats thrive amid so many people and so many cars.
None of the collared cats have been run over, Broman said, though traffic is their worst enemy.
“This is a surprise, particularly since we have a couple of young males with collars,” said Broman, who found that bobcats in rural areas are not smart about traffic. “Young males are the most likely to disperse into unfamiliar places. It makes me wonder if urban bobcats know something their rural relatives don’t know.”
Bobcats are hard to count. In 2009, the U.S. Fish and Wildlife Service surveyed North American wildlife agencies for estimates on bobcat numbers. The survey concluded that there are many more bobcats than previously thought and that their numbers have increased in most of their range since the late 1990s.
In most states, estimates were based on available habitat. The U.S. population was estimated at 2.3 million to 3.5 million animals. The Texas population was listed as stable, and estimated by TPWD at 287,000 to 1.3 million bobcats. Florida is the only state to estimate a declining population in that survey.
Michael Tewes of the Caesar Kleberg Wildlife Research Institute in Kingsville is one of the state’s acknowledged wild cat authorities. He estimates there are 200,000 Texas bobcats, with the highest densities in South Texas, where there have been estimates of one bobcat per square kilometer. Where Broman studied bobcats in New Hampshire, male cats roamed over 25 to 30 square miles.
Broman said his research team should be able to estimate the D-FW bobcat population once the GPS collars have distinguished home range size and which habitat the cats prefer.
“We will then combine those numbers with known bobcat behavior to calculate an estimate of how many bobcats reside in D-FW,” he said. “It is essentially a habitat-based estimate of carrying capacity.”
The study has already documented males traveling as far as 5 miles in the highly fragmented landscape. Another surprise is the high number of unique individuals captured on a single trail camera. Multiple animals observed in a single area may indicate small home ranges, overlapping home ranges or high population densities, Broman said. Bobcats have unique spot patterns that allow individuals to be identified.
Broman is particularly pleased with the public response to urban bobcats. Since August, he’s received more than 90 observations from 29 cities via the iNaturalist.org website. Search at iNaturalist for “DFW carnivores” to view the observations or to report an observation. Broman also posts bobcat information and photos on Facebook at Texas Parks and Wildlife-DFW Urban Wildlife.
One of North America’s most successful predators, bobcats often play with their prey, even the agile squirrels they’ve just caught, Broman said.
“Their hunting skills are so refined they’re almost cocky about it,” he said.“Most predators kill their prey as quickly as possible because they can’t afford to let a meal get away. A bobcat will turn its prey loose with the supreme confidence that it can catch it again.”
Broman said he’s had no reports of urban bobcats preying on domestic pets. The urban study will determine exactly what the cats eat by analyzing scat. A bobcat’s teeth, essentially a mouthful of knives, are not designed to chew food. Identifiable bits of prey can be found in the cat’s droppings. He said the rise in urban bobcats may be partially due to backyard bird feeders that attract mice and rats at night, squirrels and birds during daylight hours.
Creek and river drainages are corridors used by many urban wildlife species, Broman said. The GPS study will identify how bobcats use green spaces, and he hopes to work with municipalities and developers interested in saving those corridors for all wildlife.
Scientific name: Lynx rufus. Lynx refers to the bobcat’s eyes that shine bright green at night, and rufus refers to the cats’ reddish coloration, though they vary in color from charcoal to blonde.
Range: Throughout North America.
Size: The average adult male caught for the urban study weighed 23 pounds, and the adult female’s average weight was 17 pounds. The biggest bobcat caught for the study, a male, weighed 28 pounds.
Number of bobcats in Dallas-Fort Worth: To be determined.
Risk to humans: None, except for rabid cats (rabies is rare in bobcats) or cats that feel cornered. Do not feed a bobcat. It could lose its fear of humans or come to view humans as a source for food.
Risk to small pets: There is the potential for a bobcat to perceive any small animal as a food source, but it doesn’t happen often with pets. Stay with your pets when you let them out, particularly at night, and turn on lights in the backyard. Though it can easily kill animals its own size and bigger, a bobcat is not a threat to a dog of equal size.