Big Creek Reserve

News from Landels-Hill Big Creek Reserve

milk thistle

October 1991-John Smiley

Last June 15 we held the third annual “Fourth of July” butterfly count at Big Creek. I assisted four butterfly experts around the reserve, nets in hand, from about 9 AM to 5 PM. We counted all the butterflies seen, and identified them to species if possible. One type of butterfly, the Painted Lady, was so abundant that we could not effectively count them all, but nearly all the others seen were counted. Our counters (three from UC Berkeley and one from the Santa Cruz city museum) were so expert that, of 872 butterflies seen only 14 could not be identified. 36 species were seen, including 2 species of swallowtail, the California Orangetip, two sulfurs, a marble, a cabbage white, two hairstreaks, six blues, a copper, the California Sister, the Buckeye, an admiral, the Tortoiseshell, three checkerspots, two crescents, an anglewing, the Painted Lady, two fritillaries, the Monarch, the Ringlet, and five skippers! That’s a lot of species, but only a small fraction (only 5%) of the total diversity of moths and butterflies found on the reserve.Last year, with five counters, we saw roughly the same number and diversity of butterflies, but with seven different species! In general, there seemed to be fewer butterflies than last year, which the counters “made up for” by working harder and covering more miles. Julia Smith, a “birdologist” working at Big Creek, agrees. The Song Sparrows she is studying are laying fewer eggs, later in the season, than in previous years. Since they generally lay eggs in proportion to the amount of food they can gather, she concludes that there is a shortage of insect food this spring (including butterflies). Perhaps the cool weather in April and May is the cause. Insects generally thrive more and develop faster in warmer weather.

We have really “hit” the Milk Thistles hard this year, and relatively few of these spiny weeds can be found on the reserve. Five years ago these plants formed dense thickets on ridge tops and benches. Thanks to the cessation of cattle grazing (which creates bare ground favorable to thistle germination), improved road maintenance techniques, the drought, and the great efforts of our machete-wielding steward Feynner Arias, we still hope to reduce this weed to an “interesting exotic.” (9/9/91)

April 1991-John Smiley

Until the rains in March, Big Creek was as low as anyone had ever seen it (it was running 3-4 cubic feet per second instead of 6-10 which is a “normal” base flow in the fall). On the slopes and ridges the soil was dry, and the annual plant cover on the hillsides was sparse and about one inch high. Even in the canyon bottom the banana slugs were inactive. I have noticed that some weeds seem to be hard-hit by the drought, including Milk Thistle (Silybum sp.). We are trying to control this species and are hoping to really knock back the thistle on our grassy ridges between 500 and 1500 feet elevation and give the bunch grass and native flowers some good soil!

The Harbor Seals are back in full numbers after their annual disappearance in August and September (does anyone know where they go?). Several Mountain Lions returned to the lowland areas of the reserve, after an absence of about 6 months. A group of three lions have been active near Boronda Camp (probably a mother and two young). They were sighted on February 23, and that evening one or more lions made screaming and growling noises around a UCSC environmental writing class. On March 4 a young lion walked through our yard and sat under a cypress tree for an hour while it rained. It was thin and lanky, even for a mountain lion, and had a pretty face with huge tawny eyes and a cream colored chin. Rosie was fascinated! Lions rarely bother people, but children are vulnerable, especially to young animals. We have no dogs and are always careful with our two little ones. We didn’t see our little black cats for two days.

The Black Oystercatchers are beginning to hang around their nest rock in Big Creek cove. Last year they raised two chicks in the nest (one survived). These birds are very sensitive to disturbance because they must guard their nest from gulls 24 hours a day. Gulls seem to “hang around” the nest, and, if the parents are scared off the gulls eat the eggs and chicks immediately.

The bay trees are in full flower now, as are pink flowering currants and manzanitas. The redwood sorrel has sprung up after the rain, and a few milkmaids are blooming. Up on the ridges there are a few buttercups, lilies and yellow violets, but really very few flowers are in bloom. Maybe the rain will make a difference and we’ll get some spring flowers soon.

A reminder: We are planning our annual open house for Saturday May 11 this year, between 9 and 4. We will have displays about the reserve, including our facilities planning efforts, and I invite you to come and see what we are up to. Like last year, we will lead hikes on the trails, so bring your lunch and plan to spend all day if you can. Unlike last year, I don’t expect to discover a dead mountain lion in the trail, but who knows? (3/5/91)