On the Trail of the Pipevine Swallowtail or a Pit Stop in Redding

    As we may have mentioned in a previous blog, there are precious few larger butterflies west of the Cascades.  Over the past few weeks we have seen about half a dozen Western Tiger Swallowtails between Portland and Seattle.  Aside from a plethora of medium sized white Cabbage Butterflies, that is it.  

California Pipevine Swallowtail, Whisketeytown NRA.

    A couple months ago we had toyed with the idea of driving south to visit my nephew Andrew and his better half, Shawn Barille, in Oakland.  This would have taken us through the Siskiyous and down into the Sacramento River Valley.  In researching this journey from the standpoint of lepidoptera, I was drawn to a picture of the Pipevine Swallowtail taken in a National Forest park in the Trinity Alps.

     I contacted the ranger at the Whiskeytown National Recreation Area, the place where this fantastic picture was taken, and he replied, saying that it was relatively easy to see the Pipevine Swallowtail in season, ie. through the end of June, and listed some five mile hikes that would take me to lush stands of pipevine and, with luck, the butterflies.  Obviously he did not recognize his correspondent as someone who watches birds the American Way, which is to say that you drive your car to the spot where you expect to see the bird and identify  the little devil without losing sight of your vehicle.  

 

 

    I then looked at the map and noted that Redding wasn't too far from those mountains.  Not only that, but the thriving metropolis actually spans the freeway.  Thinking that there might be butterflies in the vicinity, I wrote to my bird watchng colleagues at the Wintu Audubon Society.  It took a bit of convincing for me to accept that (what with the peculiar name)  this was, in fact, the Audubon Society of Redding, California,  but they had a nice web page and suggested a couple ways for me to contact members.   In a few days I got a reply from a nice man by the name of Dan Greaney who wrote:

Pipevine Swallowtail, Redding. CA.  June 2021 S. Barille photo

    Hi Jeffrey,  Pipevine and the swallowtails are all over.  One easy access is to go over the Sundial Bridge and follow the trail upriver.  Pipevine decks the fencing along the trail,

    As it turns out, the Sundial Bridge is a cute pedestrian bridge, illuminated at night, that spans the Sacramento River as it descends from the Coast Range into the valley.  It is mere minutes from the freeway and hotels appropriate for a night's stay with my sweetie.  

    Regrettably, as plans were being formulated, Shawn and Andrew were called upon to head up to Seattle at about the same time we might have been heading down to San Francisco Bay.

    All this brings us to yesterday.  I was standing in the rain looking wistfully at sailboats while the aforementioned sweetie was shopping with her lovely daughter on the mercantile end of Hayden Island in north Portland.  As I stood there, much like the Water Rat from Wind in the Willows, thinking of  just messing around in boats, who should call but Shawn ad Andrew.  They were in their SUV, driving north on I-5, just an hour south of Redding.  Suffice it to say, it didn't take long before I was imploring them to stop in Redding and look for the Pipevine and the Swallowtail.  Shawn already knew about the Sundial Bridge  (it must be the biggest tourist attraction within a fifty mile radius) so relating the instructions for finding the Pipevine Swallowtail and its eponymous host plant was a snap. 

Possibly a female Pipevine Butterfly S. Barille Sundial Bridge 6/21

   They accepted their assignment happily and, much like Carl Linnaeus, I got back in my car, out of the rain, and waited for someone else to find animals for me. 

   At this point I ask you to to be kind when comparing the Academia at Uppsala University with a 2018 Mazda 3 in north Portland.  In both cases it was probably raining.

    Talk about service with a smile.  In less than an hour I was receiving movies and still photos of the object of my desire.  The dynamic duo had no trouble finding the bridge and walking to the far side where, only steps away, there were lots of butterflies.   Andrew described the  butterflies as both beautiful and energetic.  

   Despite the vigorous flapping of wings, however, the butterflies remained close enough for some remarkable photography.  Butterflies frequently fly away before Sandra and I can snap a picture.  In Hawaii we have found that the host plant, Crown Milkweed, will keep Monarchs close by.  And some well tended flowering plants will hold the Gulf Frittilaries as they feed.   Good luck attempting a photograph of a butterfly on the wing. 

The thrill of discovery.  Andrew and Shawn at Sundial Bridge.

    Andy supplied us with the movie that you see above, which I find utterly fascinating.  I am assuming that we are looking at a pair of butterflies. In this instance, its likely that pipevine, their host plant, has drawn the butterflies to the area.   However, one of the pair is clearly engaged in nectaring on a stand of violet colored wildflowers.  The one that is not feeding is the darker of the two, the one we suppose is the male.  Look at the way he attentively flutters around his mate.  What do you suppose is keeping him in the picture? 

   Hence, Andrew's movie captures all three of the of the factors that guide the butterfly phase of these amazing invertebrates:  the host plant the caterpillars will feed upon, flowers that provide sustenance to the adult butterfly, and the chemical messengers that bring the sexes together, resulting in eggs.

  The literature suggests that among California Pipevine Butterflies the dorsal hind wing of males is more iridescent blue than the female.  According to the California Academy of Science, this is the only difference.  However, the differences we see in Shawn's pictures and the movie  are greater than that.  One butterfly, I assume the male, is just as you would expect, black with a blue dorsal hind wing.  What I believe is the female is almost a drab gray.

    Feel free to look at the picture from Whiskeytown NRA and compare that butterfly, also in resting position, with the one in Shawn's second photograph.  In both pictures we see the ventral surface of both wings. The wings of the Whiskeytown butterfly are black.  Shawn's are dusty gray.  And the spots on the hind wing are orange on the former and almost white on Shawn's.  If you look carefully at the movie, you may get a feel for the dorsal surfaces of the feeding, gray butterfly. 

    If you are not familiar with butterflies, you might think that there may be significant variation from individual to individual, but within a small geographic area, I don't believe that this is the case.  Hence, I will propose that there is greater sexual dimorphism in the California Pipevine Butterfly than the California Academy of Science would have us believe. 

   Keep in mind that Andrew's movie, and Shawn's still photos were taken with cell phones.  I think their results are amazing.

     Well, that is this week's butterfly story.    The paper mache butterfly exhibit opens later this week, so you can anticipate an exciting report.  in the meantime, keep your antennae tuned to the three Fs:  Food, Foliage and Pheromones!   

jeff

Beavers Shirt and Batman Cape.  Our grandson Reid keeps a sharp lookout for butterflies.  

                                                    Photo by Gramma Sandra