Nature Notebook, March 14, 2019


The vernal equinox of March 20 is the first day of spring in the Northern Hemisphere and a full moon. With sun directly above the equator, we experience equal amounts of day and night; then the earth begins tilting toward the sun and our days grow longer until the summer solstice.

Wildflower season is off to a slow start as we await warmer temperatures to tempt plants into budding and flowering. California bay trees typically flower from December through April and then produce nuts that ripen by fall. In the meantime, massive fields of lemon-yellow mustard are cropping up. These bright plants are native to western Europe and the Mediterranean countries; introduced to California during the 19th century mission period, they are often found in grape vineyards. 

As Northern elephant seal visitors return to sea, year-round harbor seals are coming ashore for their pupping season. Harbor seals move into Drakes Estero and Tomales Bay seeking sandbars and quiet beaches to deliver their pups. Like the elephant seals, harbor seals nurse for about a month. Normal adult seal behaviors include leaving a pup alone onshore as they look for food—give all marine mammals a wide berth.

Winter rains have been reshaping the landscape. Slides have undermined roads and collapsed cliffs across the Point Reyes Peninsula, and Chicken Ranch Beach has been remodeled as creeks overflowed and brought more sediment into the bay. Please be careful and stay away from cliff and creek edges where water softened soils are often prone to collapse.