Wednesday, May 13, 2015

Time for the Animals

It's really important to be aware and mindful of the hours the Preserve is open for recreation (sunrise to sunset).  Please plan your hikes accordingly so that you don't begin before sunrise and if you hike in the afternoon, start early enough so that you're out before sunset!  You can visit our website at for sunrise/sunset hours and up-to-date information on trail closures.   

Animals have natural biological rhythms and adaptations influencing whether they are active during the day (diurnal), around dawn/dusk (crepuscular) or at night (nocturnal).  However, the external environment can be a driving force in altering that natural pattern. 

The Puente Hills Preserve is home to a wide range of crepuscular and nocturnal animals including, but not limited to, the following animals:
  • Crepuscular: cottontail rabbits, mule deer, mice, rattlesnakes, hummingbirds, songbirds, mosquitoes, moths, some beetles
  • Nocturnal: foxes, owls, bats, mule deer, skunks, raccoons, bobcat, coyote, mountain lions, rattlesnakes

Benefits of being crepuscular
There are numerous benefits of being crepuscular.  The temperatures around dusk and dawn can be the most comfortable time of day especially when daytime and nighttime temperatures can be more extreme.  In low light conditions, animals can blend in better to their surroundings allowing them to hide while they forage.  Being crepuscular also allows many animals to avoid predators by being active when predatory animals, such as mountain lions and bobcats, are typically not.  But also many species, such as mule deer, have eyes adapted to see in those light conditions.  During this small window of time (currently approximately 1.5 hours before sunrise and after sunset), crepuscular animals must feed, find mates, seek shelter, etc. and many species are only active during the crepuscular and/or nocturnal hours.

General recreational impacts
Some diurnal animals of the Puente Hills Preserve, such as the California ground squirrel (Spermophilus beecheyi) and the Western Scrub-Jay (Aphelocoma californica),   may become habituated to recreationists during the day because of the regular activity going on around them.   However, there are more people on the trails than before (use at Hellman increased 798% between 2005 [Martino et al. 2006] and 2012 [Garbat et al. 2013]), and when recreation levels in the Preserve were much lower, there was presumably less recreation use between sunset and sunrise.  Rangers are now spending increasing amounts of time trying to get recreationists out of the Preserve at sunset.  This increased level of recreational activity may cause crepuscular and nocturnal wildlife to become alarmed by human use and modify their behaviors, potentially having deleterious effects on their survival (e.g. increased heart rate, decreased foraging) and/or breeding (e.g. nest abandonment).  With increased human use, especially after sunset and before sunrise, concerns are that these effects on wildlife may become amplified.  The type of activity recreationists are engaging in may also matter since hikers may be more likely to approach wildlife and travel slower than bikers so they have an increased time of disturbance in one area. Papouchis et al. (2001) found that hikers caused the most severe responses in desert bighorn sheep where sheep fled in 61% of the encounters with hikers as compared to 6% of encounters with bikers.  Wildlife may have energetic losses when they are intentionally or unintentionally harassed and flee from their normal activities or preferred habitat expending more energy on fleeing/flight in addition to the potential loss of foraging time.    Additionally, noise may disturb wildlife and it is typically quieter in the Preserve during the crepuscular and nocturnal hours.  In some studies, noise caused by visitors resulted in increased levels of disturbance to birds (Bowles 1995; Burger & Gochfeld 1998).  In general, the presence of dogs were found to cause birds to flush (Burger 1986; Pomerantz et al. 1988;) and unleashed dogs were found to pose a direct threat to birds because they can chase and kill them (Burger 1986), and they may be especially disruptive off-leash due to their resemblance to coyotes and foxes (Sime 1999), thus eliciting a predator avoidance response by wildlife. 

Crepuscular/nocturnal use impacts
With such little time for crepuscular animals to accomplish their daily activities, recreation during this time may interrupt these activities with potential negative effects on wildlife.  With more people on the trails now and user-created trails bisecting habitat, pressures on wildlife from recreational activities can cause many diurnal animals to shift their activity times to being more crepuscular or even nocturnal (George and Crooks 2006).  Therefore periods of relief for wildlife, such as during the crepuscular and nocturnal hours, become increasingly important.  The biggest effect is the cumulative effect of nighttime disturbance on wildlife that has already been displaced or disturbed by human activity during the daytime (see general recreational impacts above).  Additionally, if people are in the Preserve at twilight/night, and using lights, those lights can impair wildlife’s vision which can disrupt foraging and young rearing, to name a few (Green and Higginbottom 2001). 

Studies on/near the Preserve
Most recently Whittier College senior, Bo Gould, has been analyzing USGS wildlife camera data (unpublished) for bobcat, coyote, gray fox, mule deer, raccoon, and striped skunk from 12/30/2012 to 6/30/2013 and analyzed what percent of the wildlife detections occurred in the daytime versus the nighttime.  These data indicate that these species may be shifting their activity times at Turnbull Canyon and Hellman Park into the nighttime compared to the core habitat where they are active in both the daytime and nighttime.  The cameras at Hellman Park, Turnbull Canyon and the core habitat were active for 147 days, 170 days and 181 days, respectively which can account for some of the higher number of detections at Turnbull Canyon and the core habitat.

Several other studies have been conducted on or near the Puente Hills Preserve investigating the effects of recreation on wildlife.  A 2002 report by Haas and Turschak stated that coyote and mule deer shifted their activity times to more nocturnal hours after opening the Colima tunnel within the Puente Hills Preserve to human recreation; a pattern which continued during a follow-up study conducted by Lucas (2010) but now also included a nocturnal shift in bobcat activity.  This may have negative effects like decreased feeding efficiency, increased predation, and increased energy demands. 

In a study conducted on the Nature Reserve of Orange County (within 40 miles of the Puente Hills Preserve), George and Crooks (2006) found that in areas with high human activity, bobcats and coyotes were less active in the daytime and exhibited a lower range of activities.  Bobcats were found less frequently along trails with high recreation use (hikers and bikers) and were more nocturnal, versus diurnal, in areas with high recreational use (again hikers and bikers) and when dogs were present. Although coyote activity was also lower in sites with higher recreation use and coyotes were also temporally displaced by dogs, they were not as sensitive to human disturbance as bobcats.  In short, the study by George and Crooks illustrates that recreation use can alter wildlife behavior.  These are important findings since our Preserve has both hikers and bikers, allows dogs in more areas than not, and bobcats and coyotes are present on the Preserve and as top predators are good indicators of ecosystem health. 

With the continual added pressure due to increased human activity during the day, it becomes more important to provide relief to wildlife during crepuscular and nocturnal times.  In addition, other challenges to the Preserve are limited Ranger resources to control human activities and close all trailheads at sunset as well as porous access points when the Preserve is closed. 


Bowles A. E. 1995. Response of wildlife to noise. Pages 109-156. in R.L. Knight and D.N. Cole, editors. Wildlife and recreationists: coexistence through management and research. Washington, D.C., Island Press.

Burger, J. 1986. The effect of human activity on shorebirds in two coastal bays in northeastern United States. Biological Conservation 13:123-130.

Burger, J., and M. Gochfeld. 1998. Effects of ecotourists on bird behaviour at Loxahatchee National Wildlife Refuge, Florida. Environmental Conservation 25:13-21.

Garbat, A.,  A. Gullo, and L. Longacre.  2013.  Trail visitor user survey. A Pilot Study of Visitation at Hellman Park and Turnbull Canyon. 
George, S.L. and K.R.  Crooks.  2006.  Recreation and large mammal activity in an urban nature reserve.  Biological Conservation 133:107-117.

Green, R. and K. Higginbottom.  2001.  The negative effects of wildlife tourism on wildlife.  Wildlife Tourism Research Report Series: No.5.

Haas, C. and G. Turschak.  2002.  Responses of large and medium-bodied mammals to recreation activities: the Colima Road underpass.  Final Report.  23 pages.

Lucas, S.  2010.  Changes in Large and Medium-bodied Mammal Activity Following Eight Years of Recreation and Other Activities: The Colima Road Underpass and Vicinity.  Final Report.  29 pages.

Martino, D., T. Longcore, and J. Wolch.  2006.  Park Visitor User Survey for the Puente Hills Landfill Native Habitat Preservation Authority.  68 pages.

Papouchis, C.M., F.J. Singer and W. B. Sloan.  2001. Responses of Desert Bighorn Sheep to increased human recreation.  Journal of Wildlife Management 65(3):573-582.

Pomerantz, G. A., D. J. Decker, G. R. Goff, and K. G. Purdy. 1988. Assessing impact of
recreation on wildlife: a classification scheme. Wildlife Society Bulletin 16:58-62.

Sime, C. A. 1999. Domestic Dogs in Wildlife Habitats. Pages 8.1-8.17 in G. Joslin and H. Youmans, coordinators. Effects of recreation on Rocky Mountain wildlife: A Review for Montana. Committee on Effects of Recreation on Wildlife, Montana Chapter of The Wildlife Society. 307pp.

Thursday, March 19, 2015

What Makes Them Tick - By Bo Gould (intern)

There are plenty of good reasons to stay on marked trails throughout the Puente Hills Preserve. For one, these lands are gradually returning to their native condition as vegetation reclaims degraded terrain. The surrounding natural landscape is also home to abundant biodiversity including rare and endangered native wildlife species that depend on native habitat. Furthermore, off-trail areas contain risks to humans like cactus, poison oak, and rattlesnakes. If all of this is not enough to keep you (and your pet if allowed) on marked trails, there is another creature that could be lurking in any shrub or grass, one that will suck your blood given the chance and this time of year can be their peak activity time!

Ticks are small parasites that belong to the arachnid family. They can be identified as having eight legs and two claw-like appendages called palpi. Two of the most common tick species in California are Ixodes pacificus (commonly known as western black-legged or deer ticks) and Dermacentor occidentalis (Pacific Coast tick).

Both of these species live by attaching to their host---usually a mammal or bird---and feeding on their blood. All ticks have four life stages; egg, larvae, nymph, and adult. Larval ticks hatch with 3 pair of legs and acquire fourth pair after their first blood meal as they enter the nymph stage. Nymphs tend to be very small, live on the ground, and are difficult to detect. Incapable of jumping or flying, adult ticks exhibit a behavior known as “questing.” Questing ticks hold on to branches or grasses with their third and fourth pair of legs and stretch out their first pair of legs to attach to potential hosts passing by. These hardy, blood-sucking arachnids are active year-round (although activity increases after the first of the year) and prefer moist, warm locations. 

Ticks don’t actually cause diseases themselves but can be vectors of various human and animal diseases in their nymph and adult forms. In California especially, deer ticks have been known to transmit Lyme disease, caused by a bacterium. Although most research reports that only a small percentage of ticks are infected with the disease, it is always important to check for and remove ticks from yourself and your pet after a hike. There are several important precautions that should be taken to protect you and others from tick bites and the infections they may carry:
  • Wear long, light-colored pants and shirts that make locating ticks easier
  • Stay in the middle of trails to avoid brushing against vegetation
  • Check yourself and others periodically
  • Always thoroughly inspect pets and brush them after a hike
In the event of an attached tick, remove it immediately with a pair of tweezers. Be sure to attach the tweezers close to the head, and pull it out slowly. It is important not to leave any mouthpart in the skin as it may cause an infection. Do not use heat or chemicals to remove the tick. Research suggests that it can take hours to days for a tick to transmit the Lyme disease bacterium. After removing the tick, you may want to consult a physician for antibiotic medication. Keep an eye on the bite location for a rash that resembles a “bulls-eye” and note any flu-like symptoms as they are indicators of Lyme disease.

With all this in mind, don’t let ticks prevent you from experiencing the beauty and serenity of the Puente Hills Preserve. Just stay aware, become educated, and be responsible while visiting the outdoors and enjoy!

For more information about ticks and Lyme disease transmission, visit or

Friday, September 26, 2014

Shaking it Up with Rattlesnakes - by Bo Gould (intern)

The Puente Hills Preserve is home to an intricate array of native plants, mammals, birds, insects, and reptiles, among others, all of whom play a vital role in supporting the health of the ecosystem. While visiting the Preserve’s beautiful natural scenery and observing its abundant wildlife, there is a group of southern Californian natives that can be particularly exciting to meet; the rattlesnakes. If you have visited the hills recently, you may have come across signs at a trailhead warning about the dangers of this reptile. However, there are many aspects of this snake that make it a special and integral part of the Puente Hills wildlife community.

Western Rattlesnake
Red Diamond Rattlesnake
In all, there are 32 known species of rattlesnakes; 7 of which can be found in California. The Puente Hills are home to two of such species; the western rattlesnake (Crotalus viridis) and the red diamond rattlesnake (Crotalus ruber). Both species can often be observed slithering among trailside grasses, stretched out on a trail or sunbathing on rock outcrops, and can grow to be over 3 feet long. The western rattlesnake is distinguished by tan and dark-brown blotches, a triangular head with pit heat-sensors on both sides, and two internasals at the tip of its head. The red diamond rattlesnake, as its name suggests, displays reddish to tan diamond-shaped scales with black-and-white bands along its tail. The coloration of rattlesnakes helps them to effectively camouflage themselves in the environment and stay well-hidden from predators.

When these snakes shed their skin, each shedding produces a new rattle at the end of their tails. These rattles are definitive characteristics of the snake and can be heard as a warning signal to potential threats or predators. Rattlesnakes will typically give a short rattle as a warning, which will grow to a steady loud rattle if the snake feels threatened. If you hear a rattlesnake, do not move until you locate the precise location of the snake, back away slowly, and keep a safe distance. Rattlesnakes rarely strike if they are unprovoked.  Never attempt to pick up a rattlesnake!

Like all pit vipers, rattlesnakes are equipped with an exceptional set of sensory organs that help them locate prey. These include pits at the tip of their nose to sense thermal radiation from warm-blooded animals, eyes adapted to nocturnal use, and a keen sense of smell from both nostrils and sensory tissues on their tongues.

Once a prey animal is located, rattlesnakes use their quick striking ability and fangs to inject powerful hemotoxic venoms. The venom travels through the blood of the prey, causing intense swelling, pain, and tissue damage. The main prey of Puente Hills rattlers are rabbits, squirrels, rats, birds, lizards, and some insects. Though rattlesnakes are effective predators themselves, they are also heavily preyed upon by hawks, crows, foxes, raccoons, and coyotes. Thus, the ecological significance of rattlesnakes is large as they help to regulate rodent populations and provide food for other native Puente Hills species.  

Although rattlesnakes are dangerous, the likelihood of being bit is very low. If you see a snake, stay calm and slowly move away. Remember to stay on designated trails within the Preserve and scan the trail ahead. If a snake is directly in the path, keeping a safe distance and stomping your feet is usually enough to coax the rattlesnake to sun in a new spot. In the case of a snakebite, do not panic! Remove all rings, watches, and anything else in the area of the wound that may restrict blood flow. Remain calm and call 911 immediately. If treated promptly, rattlesnake bites are almost never fatal. You are more likely to be struck by lightning than to be bit by a rattlesnake.

So when on the trails, keep an eye out for this important part of the Puente Hills ecosystem and watch your step!

Tuesday, July 22, 2014

Living With Coyotes

HELP KEEP COYOTES WILD                

Coyotes help the environment.  They help keep populations of rodents and other small mammals under control. They also feed on raccoons, birds, insects, fruits/vegetables, human garbage, outdoor pet food and small pets left unprotected (even in your backyard). 

Attacks on humans are very rare.  When coyotes become accustomed to humans they can lose their shyness and become more demanding.  An average adult coyote is about 35 pounds and will be intimidated by people. While they may stop and observe, they will eventually run.  Coyotes can be seen any time of day but are typically most active at night; some have even become year round residents of urban areas.  They also become very active and visible during the pup-rearing season (May – July).

Associating urban areas with food.  To coexist, it is important that coyotes do not associate urban areas with food.  Coyotes are naturally fearful of humans, however they readily lose that fear when people intentionally (or unintentionally) provide food/water or shelter for them, or otherwise do not try to deter them from visiting. Eliminating sources that attract coyotes can go a long way in addressing the situation. 

What can you do?
  · Do not feed coyotes and other wildlife.
  · Make sure outside garbage is secured and fallen fruit from trees and bird seed from bird feeders is picked up. 
  · Do not feed your pets outdoors or leave pet food and water outdoors unattended, especially at night. 
  · Do not allow pets to roam free outside (including in your backyard), especially at night; make sure to keep your dog on a leash during walks.
  · Keep your landscaping trimmed and open so that they don’t provide hiding places for coyotes or other wildlife.
  · Make sure that fencing around your yard is secure –six-foot tall and buried six inches deep is recommended to prevent digging underneath it. 

If approached by a coyote or if one is in your neighborhood:
  · "Haze” them. Stand tall, yell, wave your arms, blow a whistle or horn, bang pots or pans together, spray water or throw rocks.
  · While they may stop and observe, they will eventually run.
  · Do not run away or turn your back on them. Stand your ground and then back   slowly away while practicing hazing techniques.
  · If you feel your personal safety is immediately at risk, call 911.

Informative links and contacts:

City of Whittier:

California Department of Fish and Wildlife:

Police Department: 562-567-9200 (non-emergency)                        

LA County Animal Control: 562-940-6898 (dead animal pickup)           

Thursday, February 13, 2014

It’s the Great Backyard Bird Count

If you’re interested in citizen-science and birding then this is the weekend for you!  Started by Cornell University and the National Audubon Society, the Great Backyard Bird Count is scheduled for February 14-17, 2014.  Citizens are being asked to collect data on wild birds and submit them online.  It can be as simple as counting birds for at least 15 minutes in your backyard for one day or participate by visiting numerous locations over the 4 days, it’s up to you. 
In 2013, there were participants in 111 countries that counted over 33 million birds! These data can assist researchers in answering questions related to how climate change can affect bird populations, timing of migrations over years, and differences in bird diversity in urban, rural and natural areas, to name a few. 

To get started, go to the following link and register online.  All the information you need to participate is on their website.
I know I’ll be participating….will you?

Happy Birding!

Tuesday, September 10, 2013

Rodenticides....Unintended Consequences

 If it’s sold on store shelves, it must be safe…right? Not always.

In 2008, the U.S. Environmental Protection Agency (EPA) released new safety measures intended to reduce children’s exposures to rodenticides in the home and reduce risks to wildlife. These measures were to be implemented by 2011 but not all companies complied with the measures.  In response, the EPA recently took action to remove 12 rodenticide products from the market but pending litigation has stopped the ban for now. 

So what’s all the concern since rodenticides kill rodents?  Yes, rodenticides contain active ingredients that kill rodents in varying ways. However, they can also kill or seriously compromise the health of non-target wildlife, children and pets. The Red-tailed Hawk, Great-horned Owl, Bobcat, Mountain Lion, Gray Fox, Red Fox, Black Bear, and Turkey Vulture, to name a few, are species that can be negatively impacted by rodenticides.  In California, the Department of Pesticide Regulation (DPR) has determined that impacts to non-target wildlife by second-generation anticoagulant rodenticides are a statewide issue and is proposing new regulatory action (No. 13-002) to designate those rodenticides as restricted materials and limit the placement of aboveground baits.

So what are rodenticides? Rodenticides are pesticides that contain active ingredients that can be classified into three types: 1) acute toxicants (AT’s), 2) first-generation anticoagulant rodenticides (FGAR’s) and 3) second-generation anticoagulant rodenticides (SGAR’s), and they are placed indoors or outdoors in tablet, pellet and/or paraffin block form. They can even be contained in bait stations. Acute toxicants work in several ways such as impairing nerve cell action or causing cell death.  With anticoagulant rodenticides, the animals’ blood loses its clotting ability and capillaries are damaged, causing the individual to die from internal bleeding. With FGAR’s, animals must consume the rodenticide several times to accumulate a lethal amount of toxin in their body and some animals became resistant to the active ingredient(s).  Therefore, SGAR’s were developed that are more toxic and designed so that lethal concentrations are consumed in just one feeding.  However, it takes several days for the rodent to die during which time it can return to feed on the rodenticide, building up extremely high concentrations in its tissues.  If it becomes prey for predators, those high concentrations of rodenticides are passed to the predator and can be lethal or compromise the non-target animals' health.  

 Aside from direct death due to anticoagulant toxicity, wildlife exposure to anticoagulant rodenticides can weaken an animals' immune system, making it vulnerable to other diseases/infections such as mange, a disease caused by a parasitic mite. Mange causes intense itching, hair loss and eventually thickening of the skin if the host animal is not healthy enough to fight the infestation.  Eventually, the skin may tear leading to bacterial infections and death.  A study conducted in the Santa Monica Mountains (Riley et al 2007) determined that two (2) mountain lions died as a direct result of anticoagulant toxicity, 90% of dead bobcats tested positive for anticoagulants and there was a high level of association in bobcats between severe mange and anticoagulant exposure. In the Puente Hills, one bobcat tested positive for anticoagulants rodenticides, at least one other bobcat died with severe mange while a third with severe mange was captured, treated and re-released. 

Currently, numerous cities and counties are showing support for the EPA and DPR by passing resolutions opposing the sale, purchase and use of certain rat and mouse poison products that pose an unacceptable risk to children, pets and wildlife.  The Board of Directors for the Puente Hills Habitat Preservation Authority passed one such resolution in August 2013 as did the City of Whittier in July 2013.  You can have your voice be heard by submitting comments to the California DPR on their Notice of Proposed Regulatory Action No. 13-002 by October 4, 2013, before 5:00 p.m. More information can be found at: 

Tuesday, April 2, 2013

Stop, look, listen!

If you’ve hiked in the Puente Hills you’ve probably heard drumming on trees or noticed horizontal holes drilled into trees with sap flowing from them; all courtesy of a group of birds called sapsuckers.  Sapsuckers belong to the bird Family Picidae that includes woodpeckers.  There are about 200
species of picids worldwide, of which two species of sapsuckers, Red-breasted sapsucker (Sphyrapicus ruber) and the red-naped sapsucker (Sphyrapicus nuchalis), have been confirmed on Habitat Authority managed land. 

The Red-breasted Sapsucker is a medium sized woodpecker with a red head, nape, throat and breast, cream colored belly, white rump and white moustache stripe.  Preferring to drill sap wells in riparian species, they inhabit forest edges and woodlands.  Breeding occurs from Alaska and British Columbia south to California and wintering grounds are located throughout most of their breeding range. They are cavity nesters and drill out new nest cavities typically annually.  Their diet consists of sap, arthropods and some fruits. 

Red-naped sapsuckers differ in that they have a red head and nape, cream breast and belly.  They breed in the Rocky Mountains and winter in southern California typically along the edges of forests and woodlands, especially groves of aspen and alder.  They are also cavity nesters and their diet consists of sap, arthropods and some fruits. 

Sapsuckers use their strong bills to drill sap holes, collectively called sap wells, into living trees and eat the sap along with some insects that are attracted to, and get trapped by, the sap.  The shape and size of the sap holes differs by species and the holes drilled in these pictures were likely made by the red-breasted sapsucker.  These sap wells can also be an attractant for species like hummingbirds who eat the sap that the sapsucker keeps flowing.  Large sap wells can cause extensive damage to trees leading to tree mortality while other times trees can heal themselves and continue growing.  Not all activities of sapsuckers are problematic.  Sapsuckers usually excavate new nests every year, leaving old nesting cavities for a variety of woodland/forest species to inhabit. 

So when you’re out on the trail, keep your eyes and ears open for these wonderful birds!