Wednesday, December 28, 2011

Should you be afraid of bobcats?

We at the Habitat Authority have gotten several calls over the years from local residents or hikers asking this very question. It is understandable for people to be afraid of things they are not familiar with, and given the relatively reclusive and secretive nature of bobcats, most people never see bobcats.

Some people are afraid of bobcats because they associate them with mountain lions. It is true that they are both wild felines. However, bobcats are much smaller than mountain lions (about 10 times smaller), and are only about the size of a beagle or about twice the size of an average housecat. (They also look quite different, with bobcats having short “bobbed” tails and a striped or spotted body, whereas mountain lions have a very long tail and are a uniform tan color). Given their small size, they also eat smaller prey than mountain lions; bobcats generally eat rabbits or rodents, while mountain lions almost exclusively eat deer.

Although there are rare reports of mountain lion attacks on people (none in the Puente Hills area), there are almost no records of bobcat attacks on people. The few credible reports that do exist generally have to do with a rabid bobcat, which is quite unusual. No reports of rabid wildlife of any kind have been reported to the Habitat Authority.

Bobcats, like mountain lions, generally avoid people and areas inhabited by people. They tend to be found less often along trails with higher recreational activity, and they often shift their activity to occur at nighttime in areas frequented by people in an effort to avoid them. Bobcat home ranges occur much more frequently in natural habitat compared to areas within or near developed areas.

If you see a bobcat in your neighborhood, it probably means that you have a lot of natural vegetation in the area. If there are a lot of rabbits or rodents in your neighborhood gardens, that might also attract bobcats. If you want to keep bobcats or other wildlife out of your yard, consider installing fencing around your immediate use area, make sure to clean up fallen fruit or other potential food items (trash, bird seed) that might attract rodents, keep small pets indoors and/or closely supervised, and never intentionally provide food or water to wildlife.

There is no reason to fear bobcats, but bobcats have plenty of reasons to fear us. In most remaining natural areas in southern California, bobcats have to face many challenges in order to survive. One major challenge is crossing numerous busy roads safely. Another challenge is not becoming infected with diseases which could be passed on from other animals or even domestic pets, and not eating rodents that have been poisoned; rat poisons contain anticoagulants and are shown to have a possible association with a disease called mange. Another challenge is finding large enough patches of habitat that are relatively free from human disturbance in order to live and rear their young.

If you do see a bobcat, you should consider yourself very lucky! Seeing a bobcat is a good way to remind us of the wildness that is still present in our area.
(Photo credits: top - Doug Wolfe, drawing - Cougar Network, time-stamped - Puente Hills Habitat Preservation Authority)

Thursday, December 1, 2011

What’s Lurking in your Firewood?

With winter just around the corner, you may be starting to buy firewood. But besides the usual critters that hang out with firewood, such as spiders or scorpions, there may be another, much more dangerous threat that is too small to see. That threat is from a small beetle, called the gold-spotted oak borer. As its name suggests, it bores into oak trees, and it eats away at their critical vascular tissue, eventually killing them. As of 2010, this beetle has killed an estimated 21,500 trees covering 1,893 square miles in San Diego County in forests, parks, and residential landscapes.

Fortunately, there are no known occurrences of the gold-spotted oak borer in Los Angeles or Orange Counties. Unfortunately, it is known to occur in not-too-distant San Diego County. If firewood from oak trees in San Diego County is transported elsewhere, it could spread the gold-spotted oak borer into new areas. When firewood is harvested, the beetle may be present in its larval stage, feeding off of the oak’s tissue beneath the bark. When that oak that becomes firewood, the beetle is transported along with the firewood. By late spring, the beetle transforms into its adult stage, with wings, and it flies out of the wood to find new oak trees on which to lay eggs. These eggs hatch into larvae, which bore into the new oak tree, and the cycle begins again.

Currently, there is no known effective remedy or treatment for the gold-spotted oak borer. Sometimes infested oak trees must be killed before others are affected. Our native coast live oak trees not only help to define the beauty and naturalness of the Puente Hills area, but also provide food and shelter for numerous invertebrates, birds, and mammals. Their importance is reflected by the fact that they are considered a protected tree species by Los Angeles County, and oak woodlands are also protected by the State. Oaks also provide shade for homes, and can even add to property values. Oaks continue to be lost to land development and other impacts, and it is important to retain and protect the remnant patches that remain. Therefore, the best hope we have in protecting our oak trees from further loss due to the gold-spotted oak borer is to prevent it from getting here in the first place. Please, check on the source of your firewood before you buy it, and avoid buying oak firewood from San Diego County. Or, if you have already purchased wood from there, burn it right away and burn it thoroughly. Help protect the beauty and natural value provided by our native coast live oaks.

For more information, visit these websites:

(photo credit for picture of gold-spotted oak borer:

(photo credit for picture of firewood:

Friday, November 4, 2011

Mixed Nuts

As some of you may be aware, parts of the Puente Hills Preserve support a rare species of native tree, the Southern California black walnut (Juglans californica). These Puente Hills are one of the handful of places in Los Angeles County where this tree is found, and it generally only grows on more moist north-facing slopes or in shady canyons. It is often found growing with another native tree, the coast live oak. In the Preserve, it can be found in the Powder Canyon and Hacienda Hills areas. The presence of walnut woodlands in the Preserve is one of the reasons that the Puente Hills was recently selected for possible inclusion in a new National Recreation Area that could encompass parts of the San Gabriel Mountains and Watershed.

The native black walnut is similar to the cultivated walnut that we buy at the grocery store, in that they both produce walnuts (although the native is smaller). One such cultivated walnut is the English walnut (Juglans regia), which is related to the native black walnut – since they are related, they can and sometimes do hybridize with each other. In the early 20th century, horticulturalists were conducting experiments hybridizing black and English walnuts, including Luther Burbank (in Santa Rosa, Northern California) and the University of California Department of Agriculture. The latter planted one of these hybrid trees in 1907 in the City of Whittier, known as the Paradox Hybrid, where it still stands today at about 14 feet tall and about 100 feet in diameter – an enormous, gorgeous tree (see photo below)! It is actually a Registered State Historic Landmark Number 681 (located on Whittier Boulevard near the intersection with Mar Vista).

If you hike in Powder Canyon and look closely at the walnut trees you may notice that a few of the trees are much larger, and have much larger leaves, but have very few fruits (often none). That is because some are the native black walnut (the smaller trees with smaller leaves and lots of fruit - at left) and some (possibly 5%) are the black-English walnut hybrid (the larger trees with larger leaves and few fruit - at right). The bark of the native black walnut is very furrowed or “grooved”, whereas the hybrid has either smooth bark (like the English walnut), or bark that is somewhere in between. So how did these hybrids get there? One possibility is that they are the result of black walnuts hybridizing with a nearby English walnut that was planted on someone’s property, perhaps one of the commercial walnut orchards that used to be more prevalent in the past. Another possibility is that these were planted as acorns from a hybrid, possibly even from the Paradox Hybrid in Whittier. This latter seems likely, considering that several resources have noted that the second generation hybrids (meaning those trees grown from seeds of the hybrid) bear very few fruit, which is the case for those hybrids seen in Powder Canyon.

Regardless of their native or hybrid status, the walnuts in the Preserve provide important food and shelter resources for many species of insects, birds and mammals, and are a beautiful and shady addition to our trails.

Friday, October 7, 2011

Cozy Camera

Surprise! That is what I think every time I download the digital photos from our motion-sensor cameras located throughout the Preserve, because I never know what fun surprising wildlife photos I’ll see. But sometimes I’m also surprised by what I find inside the camera itself. Occasionally I’ll find a spider making a web, or a colony of pincher bugs. But this week I found something quite surprising – a nest! And no, not a bird’s nest; nesting season is pretty much over by now for birds, generally ending in August or September. It was a mouse nest! I believe they are common deer mice based on their orange-brown fur on the top of their bodies, and the white fur on their underside, as well as their size and ears.

Deer mice can reproduce almost any time of year, especially in our moderate climate, and use a variety of places to build nests. Apparently there was just enough of space for them to wedge into the metal box which houses the camera, and build a fluffy, cup-shaped nest. Nests are often constructed out of grasses, moss, wool, fibers, and thistle down. This nest appears to be constructed mostly of pappus from thistle seeds (“thistle down”) – this is the fluffy stuff that allows the seed to be carried off by the wind. I caught both of them as they were still constructing the nest, and when I went back to check a few days later, the nest was completed into a sphere with a hole in the top – and the female nestled inside (the male ran out of the box as I opened it). Their gestation period is about 3 weeks, so I’ll keep checking over the next few weeks to see if there are any baby mice.

Monday, August 22, 2011

The Young and the Restless

Summertime means lots of different things to different people. Here on the Preserve, one thing it means is we get to see the young animals that were born this spring and are now roaming about. Some are still with their parents, and will be through the fall. Our motion-sensor wildlife cameras have picked up several young animals that we'd like to share with you.

This fawn (on the left) photographed in Sycamore Canyon is probably a few months old in this photo, and is still young enough to still have its spots for camoflauge from predators. Their main predator here on the Preserve is likely the mountain lion, which are sometimes seen in Sycamore Canyon. Deer are very common here probably due to the proximity to the irrigted lawns at adjacent Rose Hills Cemetery, which is probably why the lion is seen here sometimes, but unfortuntely we haven't gotten a mountion lion photo yet. If you see a lion anywhere on the Preserve, contact Shannon Lucas at the Habitat Authority so we can add it to our database (

These young ground squirrels (the two on the left) are following their Mom near the entrance to the Colima Tunnel along the Arroyo San Miguel trail, although its unlikely they will go all the way through the tunnel.

This coyote was photographed just uphill from the Colima Tunnel. It appears to be young coyote due to its relatlvey smaller size and especially its fluffy coat of fur. It is possible that its parents have taught it to travel safely across Colima Road by using the tunnel, as it is heading in that direction, and there is a photo of a coyote's tail heading into the Tunnel (from another camera) only one minute later. This tunnel has been used by several wildlife species, including deer, coyote, and bobcat, to travel safely across Colima Road and avoid being hit by vehicles; unfortunately, bobcats are not seen as frequently here as they once were, but roadkill bobcats and other large mammals are often seen as roadkill at the top of the hill on Colima Road, indicating that there is not a safe way to cross Colima Road at that location. Despite posted speed limits and wildlife crossing signs, roadkill are common, so watch your speed and watch for crossing wildlife!

Tuesday, April 19, 2011

Chick Flicks

For the last two years during the month of April, we've shared photos of the red-tailed hawk chicks and great horned owl chicks in nests within the Preserve's Core Habitat (an area that is off-limits to the public to provide a refuge for wildlife). This year, with our new digital video camera, we now have some short videos to share!

The first video is of the three red-tailed hawk chicks with their mother - after she stops looking annoyingly at me (even though I'm several hundred feet away!) she continues to feed her chicks. Keep an eye out for the two chicks in the back that appear to be fighting over the leg of some unknown small animal that is now their lunch. The second video is of three great horned owl chicks and their mother - toward the end of this video, the mother moves away from the chicks, and two of them try to awkwardly follow her.

As you will see, the owl chicks are much larger than the hawk chicks, and are closer to the size of their mother, whereas the red-tailed hawk chicks are still very small. That is because great horned owls often lay their eggs earlier than other raptors, which means they hatch sooner, so they are more developed at this point in time than the hawk chicks, which likely only hatched a few weeks ago. The great horned owl chicks will soon be losing their fluffy white feathers, looking more like mom and dad, and start walking out onto the branches of their nest tree. Hopefully more videos to come!

Tuesday, March 22, 2011

Roadkill and Rodenticides

What on earth do these two things have in common? Both obviously involve dead animals. But roadkill are killed directly by vehicles on roads. Rodenticides also directly kill rodents (such as rats in homes or gophers on lawns when they eat the rodenticide) because the main ingredient is an anticoagulant, which prevents blood from clotting and eventually causes the animal to die from internal bleeding. However, rodenticides can also indirectly kill or harm other animals, such as bobcats or hawks, which can become poisoned when they eat rodents that have eaten rodenticide.

Researchers at UCLA and the Santa Monica Mountains National Recreation Area are studying a possible link between indirect rodenticide poisoning of bobcats and a disease called mange. They have noticed that bobcats that have died with mange have all had concentrations of anticoagulant compounds in their liver. Please check out to learn more about the study and alternatives to rodenticides. The Habitat Authority has agreed to assist in this research effort by collecting tissue samples from dead bobcats. The tissue is sent to UCLA, where the researchers determine whether the bobcat has mange and/or whether it has traces of anticoagulants in its system (by testing the liver).

Last week, two roadkill bobcats were found along Colima Road within days of each other in almost the same location, and samples were collected for the UCLA study. In addition, genetic material from these samples will also be shared with the U.S. Geological Survey, which is conducting a regional study of large mammals in southern California to determine dispersal patterns. So, hopefully these bobcats will not have died in vain. It is possible that they can be used by scientists to determine whether anticoagulant rodenticides cause mange in bobcats. It is also possible that they can be used by scientists to determine where our bobcats originally dispersed from, and how they are related to other bobcats in southern California. In the meantime, the Habitat Authority is studying wildlife movement across Colima Road in an effort to reduce roadkills over time, helping to maintain habitat connectivity throughout the Puente-Chino Hills Wildlife Corridor.

You can also help by avoiding the use of rodenticides, and by reporting any sick, injured or roadkill bobcats to the Habitat Authority by contacting the Ecologist at 562-201-2062 or

Friday, January 28, 2011


Much time and attention is devoted to what Biologists commonly call “charismatic megafauna” – namely, the larger and cuter animals, such as hawks or bobcats. Plus, megafauna are generally easier to spot when out on a hike or bike ride. However, there are numerous forms of “microfauna” in the hills worthy of some attention.

I recently found one such specimen while weeding a recently planted restoration area. As I was pulling out a non-native mustard seedling, I saw a worm…or what I thought was a worm. Strangely, this worm had arms and legs! So I picked it up, and sure enough, it was no worm, but a very tiny salamander – a black-bellied salamander. They really are about the size of an earthworm (generally no longer than 2 inches and about the same diameter), but with tiny legs, a tiny head with eyes, a reddish topside with a dark stripe, and a mottled gray underside.
They also like to live in moist places like worms – that is because they are a type of “lungless” salamanders, meaning that they breathe through their skin, which needs to remain moist. So, you are really only likely to see them near creeks or shady woodlands, and only in the wet part of the year – they retreat underground during the dry season.

Black-bellied salamanders are endemic to coastal Southern California, but it is not considered a rare species. During a study of the Puente-Chino Hills from 1998 to 2000, only three species of salamanders were found – black-bellied, arboreal, and garden slender salamanders. Of the three, black-bellied salamanders were the most common, and most of them were found in Powder Canyon. But the study also found it sometimes difficult to tell the difference between black-bellied and garden slender salamanders. Either way, they are a good reminder that sometimes we need to stop and appreciate the little things!