Nature Notebook, September 26, 2019


The autumnal equinox of Sept. 23 ushered in the fall season, followed by a new moon on Sept. 28. A slow meteor shower—the Draconids—also arrives, appearing from Oct. 6 to 10. At best, there may be about 10 per hour seen mostly after 1 a.m., when the thin crescent moon has set and the sky is dark. 

Our newest residents have set up camp behind Cabaline, where tent caterpillars have spun several large, frothy-white webs in the trees. They eat serious amounts of foliage as they move through their life cycle, from egg to caterpillar to moth. The tree will recover from its voracious tenants; for now, watch for caterpillars dropping and moths fluttering.

Warm waters and dark, moonless nights between the full moon cycles have created excellent conditions to see bioluminescence in local waters. Tiny dinoflagellates, single-celled living creatures, appear to glow in the waves as the water sparkles along Tomales Bay beaches.

As the acorns ripen, look for increased activity from acorn woodpeckers around Bear Valley. They are drilling fence-post holes to stuff with acorns and storing the nuts under roof shingles.  As the acorns dry and shrink, the woodpeckers transfer them to smaller holes and will spend the winter eating insects in the acorns as well as the nut meat. These stashes keep their food safe from squirrels.