Spike in wasp population prompts warning for park visitors in North Bay

SAN RAFAEL, Calif. - State parks officials are warning park-goers in Marin County about an increase in yellow jacket activity, advising people to take safety precautions.

Officials noted there have been unusually high populations of the wasps at Samuel P. Taylor State Park, as well as other areas in Marin County.

What they're saying:

"This rise is due to a combination of mild weather conditions and increased access to water and food sources," officials explained on the park's website.

To try and keep visitors safe, officials said that the staff at Samuel P. Taylor is taking measures to find and mark yellow jacket nesting sites. 

The park is also working to relocate campers' reservations in areas where there is known wasp activity.

In addition, the park said it’s also coordinating efforts with pest control to "reduce the chance of guest encounters."

Samuel P. Taylor State Park

The popular park is located in the community of Lagunitas. It features campgrounds, picnic areas and hiking trails as well as paved trails for bicyclists.  

The sprawling 2,882-acre landscape covers redwood trails, canyon groves, "oak-studded grasslands" and rolling hills, according to the State Park’s website.

Safety tips

To protect yourself from wasp attacks, the Marin/Sonoma Mosquito and Vector Control District and state parks officials advise the following:

• Do not disturb nests.
• Avoid being barefoot outdoors.
• Refrain from swatting at yellow jackets.
• Cover sweetened drinks with lids.
• Keep garbage away from eating areas.
• When dining outside, inspect food before eating.

Yellow jacket characteristics

The vector control district warned that yellow jackets will aggressively defend their nests if disturbed. 

Experts described the insects as being "aggressive, stinging wasps… that typically have a yellow and black banded abdomen."

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The district noted that the region is home to several local species that fit this description, but noted, "Yellow jackets can easily be distinguished from paper wasps, which comparatively have a longer waist and legs."  

In a blog on the vector control agency's site, experts also explained the species can be identified by a continuous yellow ring around each eye, making it look like the insects are wearing "goggles."

The blog said the insects are drawn to outdoor gatherings, especially those involving food, and they seek protein as part of their diet.

"Western yellow jackets do not seem to understand or care that it is rude to show up uninvited to a picnic," the blogger wrote.

In ground nest control 

The wasps build nests both in the ground and above.

The vector control district said it provides free in ground yellow jacket nest control to residents in Marin and Sonoma counties.

To take advantage of this service, residents must first know the location of the nest before reaching out to the agency. 

Officials stressed the nest must be in the ground and asked residents to be sure to place an obvious marker near the location of the nest to help the technician locate it easily.

If stung… 

Experts also explained that female yellow jackets can sting repeatedly, and some people may be sensitive to the wasps' venom.

In the event of a yellow jacket sting, officials advise monitoring how your body reacts and said you should seek medical attention if needed, "especially if you experience swelling, trouble breathing, or signs of an allergic reaction."