Current Bug, Snake and Varmint Reports in the San Gabriel Mountains

Latest observations
Bobcats and Mountain Lions
Previous bug reports
Other Pests

Latest observations: This page is no longer kept current with reports, but serves to indicate which pests and beasts are problems, and if the problems are seasonal, gives the typical time when they occur.


See Bug Season in 2001 to get an idea of when and where bugs were bad then. Also see Previous bug reports for five years of records of when they were a problem.

To get an idea of how the bugs vary in time, see my assessment of the severity of bugs on my hikes from mid-1999 to late 2000. After each hike, I have estimated the severity of bugs on this scale of 1 to 10:

The plot separates my hikes into SGM, San Diego County, the Dripping Springs Trail on Agua Tibia, and the Santa Rosa Plateau. The continuous curves on the plots are made from near-daily estimates in Fallbrook, in rural north San Diego County, both for the morning and the afternoon separately. Although there is not an exact match among all curves and points, they all show roughly the same qualitative behavior. The Santa Rosa Plateau may be somewhat a special case, since the Plateau usually experiences breezes that may keep the bugs somewhat at bay.

Ticks: Ticks are generally a problem after the first fall rains until sometime around June. See Previous bug reports for five years of records of when they were a problem.

Note that the number of ticks on a given trail is extremely variable. I have hiked the same overgrown trail two weeks in a row, receiving 5 ticks one week and none the next. On 29 May 1999 while I was bushwhacking Rubio Canyon, I received no ticks, while on the same day Roy Randall reported:

I have never seen so many ticks in my life. There were some sections on this trip where I would walk 20 paces and pick 10 ticks off my legs, walk 20 more and pick off 10 more... for MILES! (This tends to slow one down a bit). I could look down and see whole armies of the little buggers advancing up my calves.

You'll never see a tick if you hike only on fireroads or trails cleared of brush. If you bushwhack, you'll probably always have a significant probability of finding a tick or two on you - William C. Flaxington reports that he finds ticks at all times of the year as he researches for amphibians off-trail.

The risk of actually contracting Lyme disease "has been exaggerated to the point of hysteria" (Dr. Eugene Shapiro of the Yale University School of Medicine, in an editorial in the New England Journal of Medicine 7/12/01). More than 90% of all cases occur in nine East Coast states, and even in the area there with the highest incidence, only 3.2% of people who had doctors remove attached ticks developed Lyme disease. Also, Lyme disease only occurs when ticks have been attached for at least 72 hours and have become engorged with blood. (Reuters, 6/12/01.)

You are ~30 times more likely to die in a car accident on the way to your hike, than to get Lyme disease. (~4200 people die per year from car accidents vs. an average of 135 cases of Lyme disease in California were reported to the CDC from 1982-2000, with 104 cases reported in 2000. (Lyme Disease in California)

See also:

Rattlesnakes: Rattlesnakes generally emerge in April, and go into "hibernation" in November. However, it is sometimes possible to find a baby rattlesnake at lower elevations at any season. See Previous bug reports for five years of records of when they have been sighted.

The number of snakes is way down since ~2001 due to the dry weather decreasing their supply of food. Scientist friends of mine who trap reptiles report finding only ~10% of the number of snakes in 2001 as in previous years, and finding almost none at all in 2002. This is probably due to snakes simply going into hibernation to await better food supplies in the future. Snakes do not have to eat very frequently, since they are cold-blooded.

This doesn't mean that you won't see a rattlesnake. For example, Linda Ainsworth reports that quite a few were seen in Monrovia Canyon on 7/14/01.

General snake advice: If you pay attention to where you are stepping, and don't pick up or try to torment the snake, you'll probably be ok. Most people who are bitten have been handling snakes, or clearing brush in their yards, not hiking. (Three bites in Poway, San Diego County, on 4/3/00 were due to brush clearing.) However, your odds of being bitten go way up if you step on (or bicycle over!) the snake before he has a chance to get away from you.

If you see a snake, please do not attempt to kill it. After all, this is its home and natural place to live. Usually the snake will move away from the trail - give it a few minutes to do that. If the snake is not dead-center on the trail, it is usually possible to pass the snake at a safe distance without getting the snake upset. If the snake won't move away, and there is not enough room to safely pass, you can nudge the snake with a long stick.

Again, please don't throw rocks at the snake or attempt to harm it. I've hiked over 1,000 miles in the SGM and encountered at least dozens of large rattlesnakes. Never once was it necessary to do anything other than wait or squeeze past the snake (generally at high speed!). I've gotten rattled at several times in high speed traverses past rattlesnakes (at what I hoped were safe distances), but never once did a snake attempt to strike at me.

If you hike frequently, you are going to meet some rattlesnakes. However, they are fairly uncommon. For example, Dave and Shirley McCunn encountered just seven rattlesnakes in four solid months of hiking the PCT from late May to September in 1981. This is a rate of ~one snake every 17 full days of hiking in prime snake season.

See also:

Bears: Yes, there are indeed bears in the SGM, an estimated 150-500 of them. There have been a number of reports of bear sightings in mid-2001.

Bears have apparently become more of a problem in 2004 since campers have not been careful about putting their food into bear-proof containers. Three bears were killed at Chilao Campground after campers foolishly left their food out, and then even more foolishly threw things at the bear to "distract it". See Food Brings People And Bears Together; Bears Pay The Price.

Here are a few encounters:

Greg E. Van Stralen has captured and tracked four black bears in the Monrovia Peak foothills. See Home Range Size and Habitat Use of Urban Black Bears in the San Gabriel Mountains for plots of how far individual bears roam, as well as reports on what they eat.

All SGM black bears have descended from 11 black bears that were introduced in the SGM in 1933, after grizzly bears were exterminated in the SGM in about 1900.

See also:

Bobcats and Mountain Lions: Bobcats (15-35 pounds, 2-3' long) and Mountain Lions (100-200 pounds, 4-5' long) definitely exist in the SGM. I finally saw my first bobcat crossing Chaney Trail Road at 11:45 a.m. on 3/16/00. Steven Bloom nearly hit a bobcat with his mountain bike on 24 December 1998 on the Redbox - Rincon Road. Dave Lewis of Ontario saw one near Vincent Gap at 7:10 am in August 1998. Because mountain lions are camouflage experts, and eyewitness sightings are notoriously inaccurate, perhaps 80% of all lion sightings are actually deer, bobcats, dogs, and even domestic cats.

Mountain lions are also known as cougars. There is only one confirmed cougar attack in the SGM: Scott Fike, a 27-year-old cyclist, was bitten and cut by a cougar near Mount Lowe on 20 March 1995, and fought the cougar off with rocks, after first trying to use his bike to shield him. The cougar was then tracked down and killed.

The general advice to avoid being eaten by a mountain lion is to travel in groups. If you encounter a mountain lion by yourself or with your children, stop, make yourself look as big as possible, and pick up small children and put them on your shoulders to make you appear even larger. Aggressively defend your position. The idea is to deter their attack by making them think that it isn't going to be easy for them. Pick up a branch or a rock to help fight them if needed. They are just big kitty-cats, so you don't want to appear as smaller prey to them. In particular, running away makes them think you are prey, and will encourage an attack.

However, you may not have to worry about taking action to prevent an attack, since mountain lions ordinarily either lie hidden, waiting for prey to approach beneath them, or approach unseen, and then attack and kill by a bite to the back of the neck that severs the spinal cord. This was the modus operandi for the attack on Barbara Schoener, a friend of my sister and a long-distance runner in excellent physical shape, in northern California.

A handful of hikers in California have been attacked by mountain lions. See a complete list of California lion attacks.

However, put this in its proper respective by noting that you are 300 times more likely to die from a lightning strike, 100 times more likely to die from a bee sting, and 50 times more likely to die from a rattlesnake bite (Beier, Paul. "Cougar Attacks on Humans in the United States and Canada," Wildlife Society Bulletin, 19:403-412, 1991). So on the scale of things to worry about, death by mountain lion hardly even makes the list. Consistent with these odds, a Forest Service employee died from a lightning strike in his Palmdale back yard on 5/23/99, and no one has even come close to dying from a cougar attack in the San Gabriels.

In my well over 1,000 miles in the SGM, I have never seen a single mountain lion, and only one bobcat. I haven't even seen a mountain lion scrape. My only encounter with a mountain lion was a distant one at the Santa Rosa Plateau. It did indeed scare me.

For more information, see Mountain Lion Attacks On People in the U.S. and Canada.

See also:


I had never thought of coyotes as a danger to humans, until a reader asked me if there had ever been any coyote attacks on people in the SGM. Although I have never heard of a coyote attack on a person in the SGM, I found that there have been a small number of attacks on people elsewhere. Almost all attacks involve small children under 5 years of age. Since 3 million children are bitten by dogs every year, your small child is millions of times more likely to get hurt by the family pet than by a coyote.

Previous Bug and Snake Reports in the San Gabriel Mountains

I stopped updating the tables at the end of 2001. Five years of data are probably enough to show how consistent bugs and snakes are with season.




"Bad" means that at some time on some hike it was not possible to be stationary without being attacked by bugs. Generally, even when the bugs are bad, as long as you are moving it is tolerable. However, sometimes it is unpleasant even to be moving as clouds of bugs attack you. Fortunately, that is usually limited to specific locations and times, so that farther along the trail the situation improves.

Since bugginess depends on the time of day, whether you are in sunlight or shade, your location and how windy it is, some hikes at some times may not be troubled by bugs even when the bugs are "bad".
More About Bugs in the San Gabriel Mountains

More About Bugs in the San Gabriel Mountains

When bugs are at their worst, here's the text I use above. Please note that this does not reflect current conditions! This text is here to more properly convey the conditions under which bugs are "bad".

Bugs of every sort are out, waiting to dine on you so they can reproduce and make more bugs. Worse, in many locations they are so numerous that they force you to keep moving and prevent stopping in places, making rest and food stops problematic. Hope for wind when you hike!

The number of bugs varies with temperature, wind conditions, time of day, and location, as well as your particular attractiveness to bugs, so your bug allocation may vary.

Fortunately, the bug severity should now be declining to a more tolerable level, since July is usually the peak month.

Here are the big four that feast on people in the SGM:

We are definitely not alone in such suffering; many other locations in the world have bugs as bad or worse than we do:

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Copyright © 1997-2005 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Last update: 10 August 2005.