Nature Notebook, July 5, 2018


Early mornings bring extreme low tides, with the lowest at -1.3 on Sunday, July 15 at 7:26 a.m. Dropping overhead are the Delta Aquarids from July 22 through August 23, peaking on July 28. It is a quiet shower, with about 20 falling stars an hour. Meteors are bits of rock, typically remnants left when a comet explodes. As the debris enters the earth’s atmosphere and speeds through the air, it generates heat and becomes a fiery rock before it burns out. 

An eruption of California tortoiseshell butterflies has been delightful to watch, with large numbers of  smallish, deep orange-brown butterflies, the second eruption I have observed in recent years. The species is known to have “massive outbreaks” every five to 13 years. Their larva feed on ceanothus shrubs and emerge from chrysalis in June and August. Interestingly, the eruptions are usually further north in California, in the Mount Shasta area, and are less common in coastal areas.  

It looks like a great year for blackberries: I’ve noticed clouds of white blossoms on prickly vines alongside local roads. Huckleberry shrubs are covered with green berries right now, requiring careful monitoring for harvesters. In the park, the annual harbor seal protection measures were lifted this week. Drakes Estero and South Blue Gum Beach are open for boating.  

Hoping to enjoy a pastry on the bench next to Cabaline? Be warned of a starling nest that is being mightily defended by one of the parents; the bird has been swooping down on passersby. I was nipped yesterday! The young may be fledged by the end of July and peace returned.