Pipevine Swallowtails In Redding

The Eastern black Swallowtail raised by Lin Batkins

    Saturday night we dined sumptuously on home made lasagna and Sunday morning we headed north out of Oakland bound for PDX.  The day before, down by the Alameda salt marsh, we had seen the Anise Swallowtail.  This was September 11th, a day significant for something bigger than butterfly observation.  But that sighting cased me to pause and reflect.  If butterflies were still flying in Oakland, why should they not still be flying in Redding, which you will recall is the stake out for the Pipevine Swallowtail.

    If butterflies are flying, this absolutely means that they are mating and laying eggs on a host plant.  Many host plants no longer have succulent leaves by mid-September, but obviously some do.  When I reviewed my correspondence with Dan Greany of the Wintu Audubon Society of Redding, he had advised that the Pipevine Swallowtail would be flying into the early autumn.  With temperatures hovering around 100 degrees, Redding was certainly not in late autumn, so it certainly seemed like a chance worth taking.

   While we are interested in any new butterfly, the PVS  hit a new category for us.  We had yet to see a predominantly black swallowtail butterfly.  If we lived east of the Rockies, that would almost certainly not be the case.  For example, the Anise Swallowtail, which we had seen the day before is considered by entomologists to be the west coast counterpart of the Eastern Black Swallowtail, which is black, beautiful and not particularly rare. Just last year, our friend Lin Batkins found a caterpillar of this species eating her dill in New Hampshire and raised it through the chrysalis to the adult you see above.  It is a charming story, but.the point here is that there are several species of black butterflies in the east and they are fairly common. Thee are only a couple here in the west and we had yet to see one.

A female CPVS.  Note the broken wing and the falling leaves.

   And so there we were, motoring across the delta of the Sacramento River and heading for Redding.  

   We arrived in Redding around 11:30.  Although it had been quite smoky here just five days before, the air was pretty clear, the sky was blue and it was only 88 degrees. It had been 108 as we motored south; that alone might have been reason enough to forego butterfly watching. 

   Finding the Sundial Bridge, with an assist from Google navigation, was a snap.  It was only five minutes from the freeway, parking was plentiful and there were nice people to point us on our way to the bridge.  

 

 

Sundial Bridge. The author and the gnommen.

    The bridge itself is somewhat of a marvel. a cantilever bridge, it has no footings in the Sacramento River, hence it does not disturb spawning salmon.  (Isn't it amazing that salmon traverse the bay and swim all this way up the river, almost 200 miles.?)  The Sacramento supplies water to, and suffers run off from, one of the prime bread baskets in our country.  The deck of the bridge is aquamarine glass which, when illuminated at night, produces a blue glow.  The soaring gnommen at the north end serves the dual purpose of supporting the cantilever and serving as one of the world's largest functional sundials, hence the name.

    We crossed the bridge and dutifully turned west on the macadam pathway.  Immediately we saw a few black butterflies fluttering in the ornamental trees planted along the path. This species of butterfly is nothing if not fluttery, constantly on the move.  We walked another 100 feet and down the slope by the river we saw many butterflies, a couple dozen at least.  Most of these were at least fifty feet away but occasionally one would flutter up too the pathway circle near us and fly off.  We stayed for about twenty minutes and in that time only two landed near enough for still butterfly photography.

A male Pipevine Swallowtail also with a broken wing.

  

Before leaving the butterflies fluttering around the Sacramento River, it's worth considering a few things.  First, especially in September. their reason on earth is to breed and produce eggs, which become caterpillars. I say especially. for it is very likely that the chrysalis these caterpillars form will be the one to over winter.  A new generation of swallowtails will emerge next spring, the progeny of these very butterflies.  

A pipevine pair flirting beneath the oaks

    As you must know by now, the California Pipevine Swallowtail, Battus philenor hirsuta, is absolutely linked to the California Dutchman's Pipe, Aristolochia californica, sometimes known simply as California pipevine.  Adult females, using their antennae, which are very sensitive chemo receptors, can identify this plant even in the fall.  At this late date the plant is no longer bearing the flowers that look like a Meerschaum pipe, the sort smoked, presumably, by Peter Stuyvesant as he traded a pocket full of beads for Upper Manhattan.  Dutch colonial history aside, the leaves of these plants produce a toxic chemical, aristolochic acid, which renders the voracious catrepillars unpalaltable to predators.  As in the case of Monarchs and milkweed, this poison passes through the pupa stage and resides as well in the adult butterflies.  Butterflyologists suggest that the orange spots on the wings of the CPVS warn birds away.  This sort of trans species communication,  aposematism, keeps the butterflies from being eaten and the birds form getting sick.

   As you can see, the two butterflies who landed near us for picture taking were a little scruffy...they both had broken wings.  But we did get some pictures and we had a great time hanging with the pipevine swallowtails.  

Sandra is standing in the shadow of 12:10

    Don't forget, before butterflies a bird watcher fluttered inside this chest.  Here in the branches of the oak tree that shaded our path, Sandra and I were treated to the chippings of a family of Plain Titmouse.  This chickadee-like bird is one of three species that occur in North America.  A nice little  bird to add to this summer's list.

    On our way out of the park, we admired the sundial.  The park architects placed a curved piece of marble about 30 yards from the gnommen and on a clear day, of which Redding has many, you can look at the shadow and tell the time.  As you see, Sandra is standing in a shadow that corresponds to 12:10 and it is time to hop back in the car and head north, with a life butterfly in the bag.

 jeff