Be careful what you wish for, lest it come true! We wished for our early season rains to continue through the winter, and they certainly have. This unusually wet winter has led to flooding across the Bay Area, and the effects have been felt on Sign Hill. Following the heavy rains on New Year's Eve, several mudslides and downed trees flanked the park's south-facing slopes. The SSF Parks team sprung into action early on New Year’s day to address the storm’s impacts. A meandering stream was designed to slow water flows and protect neighboring homes, while jute netting, straw wattles, and wooden retaining walls were installed to mitigate erosion. 

Of course these gray clouds also come with a silver lining, they have brought much needed replenishment to the plants and animals of Sign Hill. We are particularly excited to see how these rains will help support the healthy establishment of our recently installed restoration planting plots. In late January we planted three grassland restoration areas using seeds collected on Sign Hill; with the help of volunteers we individually sowed over 7,900 native seeds! 

In early February we put our student interns from Design Tech High School to work planting two restoration areas using plants started at Mission Blue Nursery. These plots were planted using an experimental design which will help us to learn what kind of site preparation works best with our local conditions. It was a special opportunity to involve young people with hands-on field work and applied science. 

I hope that you won’t miss the chance to visit Sign Hill this spring and see all the beautiful wildflowers that the rain brings!

Candace LaCroix

Natural Resource Specialist 

Leading the Sign Hill Restoration Project

San Bruno Mountain Watch Board Member

New Years Eve brought heavy rains to South Francisco and mudslides to Sign Hill. In order mitigate erosion and protect surrounding homes from the flows, SSF Parks got to work early on New Year's morning.

Before

After

To slow water flows, the stream was guided down a meandering path made of logs from downed trees.

In the upper slopes of the disturbed area, straw wattles and jute netting were applied to catch soils and prevent further erosion.

On the Hillside Sign, there was a mudslide so deep that wooden retaining walls needed to be built to prevent further erosion. Straw waddles were installed above the mudslide to prevent it from cutting deeper into the hillside.

The work had to finished before any more heavy rains started to fall. Many hands from the SSF Parks team came together to see this project through in just one day!

Introduced plants, especially highly invasive weeds, have outcompeted native plant species in many parts of Sign Hill. The native grasslands of Sign Hill provide habitat the federally endangered mission blue butterfly (Icaricia icarioides missionensis). To help restore habitat for these butterflies and other native plants and animals of Sign Hill, a series of native seed and plug plantings were installed during the wet winter months.

The restoration plantings are in areas dominated by non-native plants and near higher quality habitat areas. This will help to expand and connect mission blue butterfly habitat across the park. The plots were scraped using an action hoe in order to removed competition from non-native plants and the seed used was collected directly on Sign Hill over the course of the previous year. Across three seeding areas, volunteers planted over 7,900 seeds!

The nursery plants we installed were grown by Mission Blue Nursery, a non-profit nursery operated by San Bruno Mountain Watch which collects all their seed from nearby San Bruno Mountain.

SSF Parks Partnered with San Bruno Mountain Watch to lead a group of student interns from Design Tech High School in gaining experience in the various parts of restoration ecology, from the nursery to the field. Student interns prepared and installed two experimental planting plots that will expand mission blue butterfly habitat while also helping us to understand what site preparation methods are most effective in helping native plants to reestablish.

Regular visitors to Sign Hill may have wondered over the last year why there has been areas on the top of the hill surrounded by orange snow-fencing. This fencing was installed to protect a patch of johnny jump-ups (Viola pedunculata), the host-plant of the callippe silverspot butterfly (Speyeria callippe callippe.) The callippe silverspot was declared federally endangered in 1997.

Although callippe silverspot were likely once abundant on Sign Hill, there were no reported sightings for over 40 years. In 2021, two years into the Sign Hill Restoration Project, a callippe silverspot butterfly was spotted during a Sign Hill Stewards workday! Then in 2022, we saw two!

The callippe silverspot only has one host plant, which it needs to survive and reproduce. Because johnny jump-ups are not able to be successfully grown in a greenhouse, the best chance we have to help save this species from extinction is to protect their existing habitat and help it to expand.

In recent weeks, SSF Parks got to work installing improved fencing around this sensitive area. The old snow fencing has now been removed, so we can all take in a nice view while we protect one of the last stands of this rare and beautiful butterfly.

Wet weather upon us! This means amphibians are showing up on Sign Hill. One of the more abundant amphibians on Sign Hill is the California slender salamander (Batrachoseps attenuatus.)

This species is more active above ground from October through March, depending on rainfall. In drier months, they retreat deeper into the earth via earthworm and rodent tunnels. Since they are lungless salamanders, they breath through their skin and need to remain consistently moist.

The California slender salamander is typically found in chaparral, woodlands, grasslands and forest, hidden under rocks, logs, stumps and leaf litter. They are known as “sit and wait" predators because they rely on stealth rather than speed or strength to catch prey. Their diets consist of a variety of invertebrates, including snails, mites and isopods that they capture using their projectile tongue. A variety of insects, spiders, birds, and snakes are possible predators to the salamander. 

You can help protect California slender salamanders, by staying on trail and putting back rocks, logs, stumps and leaf litter if you happen to encounter one in your garden.

On Saturday, March18 South San Francisco Library and Parks & Recreation will host Nature Walk on Sign Hill.

This will be an opportunity for the community to explore and learn about the natural habitat of Sign Hill. Participants will experience a nature walk provided by Parks and Recreation and enjoy stories and a drawing activity provided by the Library. The nature walk is less than half a mile along the Ridge Trail and is on an incline. Participants are encouraged to wear wear walking shoes and bring water. All ages welcome. 

This event is limited to 30 guests and is now FULL. Registration is closed. To sign up for future events, keep an eye out on South San Francisco's City Calendar.