Today was a glorious day in the Ruth Risdon Storer Garden in the UC Davis Arboretum.

Absolutely glorious.

The scent of the Korean lilac, Syringa patula, drew several pipevine swallowtails (Battus philenor), their iridescent blue hind wings gleaming in the late morning sun.

Butterfly guru Art Shapiro, distinguished professor of evolution and ecology at UC Davis, calls the pipevine swallowtail "the signature riparian butterfly of our region, occurring along streams in foothill canyons and on the Central Valley floor, essentially everywhere where its only host plant, California Pipevine or Dutchman's Pipe, Aristolochia californica, occurs."

"This species is warningly colored and inedible to vertebrate predators," Shapiro writes on his website. "It derives its protection from the toxic aristolochic acids produced by the host, which it sequesters; females even pass these along to the eggs, which are also protected (and are brick red, laid in bunches of up to 20, and quite conspicuous)." 

Shapiro notes that the pipevine swallowtail flies from late winter (February-March), to autumn (October, occasionally November) but is "much more numerous before the 4th of July than later."

The Korean lilac provides a great nectar source for the butterflies.  This one in the Storer Garden is a good 10 feet all. Native to China and Korean, it's also known as "The Miss Kim Lilac," discovered by Elwyn Meador and reportedly named for his Korean assistant.

So today, the iridescent blue wings and the featherly purple blossoms collided in the air in the Storer Garden, with promises of more butterflies and blossoms to come.

Meanwhile, the UC Davis Arboretum officials are gearing up for their first public plant sale of the spring season. set Saturday, April 2 from 9 a.m. to 1 p.m. at the UC Davis Arboretum Teaching Nursery on Garrod Drive, right next to the Storer Garden.  Check out the website for the list of plants available.

Never say "pipe down" to a pipevine swallowtail.

It's a butterfly we treasure.

You may have seen it nectaring on your butterfly bush. It's black with blue iridescent upper wings and orange arrowhead-like spots on its inner wings.  

Butterfly expert Art Shapiro, distinguished professor of evolution and ecology at the University of California, Davis, says on his website, Art's Butterfly World, that Battus philenor is "unmistakable and very conspicuous as both a larva and an adult."

So are the eggs. The eggs are red or rust-colored, while the larvae or caterpillars are black with red spots. 

Shapiro describes Battus philenor as "the signature riparian butterfly of our region, occurring along streams in foothill canyons and on the Central Valley floor, essentially everywhere where its only host plant, California pipevine or Dutchman's pipe, Aristolochia californica, occurs."

The butterfly, also nicknamed "blue swallowtail," is found throughout North America and Central America.

"Adults are eager visitors to many flowers, including wild radish, California buckeye, blue dicks, Ithuriel's spear, and Yerba Santa," according to Shapiro. "In summer they regularly nectar at yellow starthisle when there are no native plants in bloom."

"This species is warningly colored and inedible to vertebrate predators," Shapiro writes. "It derives its protection from the toxic aristolochic acids produced by the host, which it sequesters; females even pass these along to the eggs, which are also protected (and are brick red, laid in bunches of up to 20, and quite conspicuous). Eggs are laid only on young, tender, growing shoot tips and the larvae must begin by feeding on these. Initially they feed in groups. As they get larger they scatter and can tackle large, mature leaves. But because these react to feeding damage by becoming more toxic and unpalatable, a larva will feed on a single leaf only for a short time and then has to move on. Eventually most or all leaves end up damaged, but few are badly damaged. The larvae also feed eagerly on the immature fruits, which look like small bananas with fluted edges. In big swallowtail years little if any seed ends up being set."

The adults live about a month.

So, let's enjoy them while we can! We followed this one around on our butterfly bush (Buddleja davidii) this afternoon as the sun dipped low in the sky. Usually, we see only the side view, but this one provided a dorsal view, flashing its colors.

Blue. Brilliant blue. iridescent blue. 

Is any other blue so glorious?

Visitors to the UC Statewide Integrated Pest Management Program (UC IPM) display in front of Briggs Hall at the 101st annual Picnic Day last Saturday at the University of California, Davis, got a close look at the Pipevine Swallowtail caterpillar.

While the visitors watched or held them, the other caterpillars kept busy, munching on the leaves of their host plant, the pipevine.

Butterfly expert Art Shapiro, distinguished professor in the UC Davis Department of Evolution and Ecology, has seen lots of Pipevine Swallowtails (Battus philenor) already this year. "There are plenty," he said today. "Don't eat 'em; they're quite poisonous."

Both the caterpillar and the adult are poisonous. The caterpillars of the Pipevine Swallowtail feed on the poisonous host plant, Aristolochia, also known as the pipevine, Dutchman's pipe or birthwort. It contains the lethal toxin aristolochic acid.

Nevertheless, the black caterpillars turn into beautiful adults. Found throughout North America and Central America, they are black with iridescent blue hind wings. Their wingspan can exceed three inches. 

"The Pipevine Swallowtail flies from late winter (February-March) to autumn (October, occasionally November) but is much more numerous before the 4th of July than later; typically it has two large flights followed by stragglers the rest of the season, often with a 'blip' upward in August," Shapiro writes on his website. "Usually the host plant stops growing in June, and thereafter there are no sites suitable for egg-laying--unless there is a local catastrophe (usually fire, though weed-whacking will do). Then the plants regenerate rapidly, producing new growth in the off-season, and any females around at the time quickly find and make use of the new shoots. Adults routinely live a month or so."

"This species is warningly colored and inedible to vertebrate predators," Shapiro points out. "It derives its protection from the toxic aristolochic acids produced by the host, which it sequesters; females even pass these along to the eggs, which are also protected (and are brick red, laid in bunches of up to 20, and quite conspicuous)."

"Adults are eager visitors to many flowers, including Wild Radish, California Buckeye, Blue Dicks, Ithuriel's Spear, and Yerba Santa," Shapiro notes. "In summer they regularly nectar at Yellow Star Thistle when there are no native plants in bloom."

We've seen many of the Pipevine Swallowtails fluttering around in the UC Davis Arboretum and gathering nectar from butterfly bushes.

A word of warning from Shapiro: "Don't eat 'em; they're quite poisonous."

Pipevine Swallowtail nectaring radish. (Photo by Kathy Keatley Garvey)

Butterfly expert Art Shapiro, distinguished professor of evolution and ecology, excitedly points to a Pipevine Swallowtail nectaring on roadside  radish. 

“Battus philenor! Battus philenor!”  

It's the earliest he's ever seen the Pipevine Swallowtail in Gates Canyon, Vacaville, one of his 10 fixed study sites in California's Central Valley.  

It is Saturday, Jan. 25. Another day to monitor the butterfly population, something he's been doing for 42 years. He posts much of his information on Art's Butterfly World.

Shapiro has trekked up Gates Canyon since 1976. He aims for 26 visits a year. In 2013 he totaled 32 visits. In a typical season, he finds approximately 30 to 40 butterfly species, "but that's not reached every year by any means," he points out. "Last year the maximum was 31."

It's a long way up and back. Shapiro, who doesn't drive a motor vehicle, rides a bus from Davis to the Vacaville bus station, then walks three miles from downtown Vacaville to Gates Canyon Road; up the road three miles and down three miles; and back to the bus station. That's a total of 12 miles.  

Shapiro works his route easily. He's like an Olympic skater as he walks up the hill: hands folded behind his back and sometimes on his hips; eyes constantly sweeping for the count.  He can, and does, detects the slightest movement, the slightest rustling of leaves, the slightest flutter of wings. 

This Saturday Art Shapiro records eight different species of butterflies or a total of 18 individuals. And not just butterflies: he spots a yellow-faced bumble bee, Bombus voznesenskii, nectaring on radish next to a Pipevine Swallowtail. 

The road up Gates Canyon, Vacaville. (Photo by Kathy Keatley Garvey)

Overall, it's a good day for "earlies." On Saturday, he sees his earliest Pieris napi, a Gray-Veined White, which beats his record of Jan. 31, 1984; his earliest Incisalia iroides, a Western Brown Elfin, eclipsing his previous records of Jan. 31 in 1976 and 1984; and his second earliest Erynnis propertius, Propertius Dusky-Wing, since Jan. 22, 1990.

Gates Canyon is bone dry. The thirsty hills and the dry creek beds ache for water. Alamo Creek, at the lower elevations, holds no water at all. At the higher elevations, the creek bed just trickles.

Shapiro's records shows that on Jan. 24, 1976, "under extreme drought conditions, I had 10 species flying at Gates Canyon. Today (Jan. 25, 2014), I had 8. Of these, only 2 were flying in '76." That amounted to 80 percent from what he detected on Jan. 24, 1976.

Shapiro keeps meticulous notes. His Jan. 25th notes include: 

"Mid-70s, 90 percent sunshine (again, a few patchy altocumulus), light noth wind not getting into the upper canyon at all. No water in Alamo Creek at lower elevations; a bit more above than on Jan. 15, actually trickling audibly in spots. Vegetation little changed: alder and bay, nothing else in upper canyon (got up to ridgetop, where there is patchy bloom of manzanita and winter currant) except a totally anomalous native Lathyrus high on a sunlit, warm rock face, being visited by Battus (but I'm getting ahead of myself); somewhat more Raphanus down below, and very little Brassica. Aristolochia still dormant. The infamous 'poison oak tree' is leafing out but most poison oak is not. A few really small buckeyes are now in early leaf; hardly any green showing on big ones, even S-facing ones. No trace of Asclepias fascicularis. No Dentaria in flower and no detectable rosettes of Dodecatheon! Few birds. Still no Phainopepla. Deer and quail; no newts; no amphibian calls."

The 18 butterfly species he sighted at his Gates Canyon study site on Jan. 25:

1. Battus philenor (Pipevine Swallowtail): 5 (new earliest at Gates)
2. Polygonia satyrus  (Satyr Anglewing): 1
3. Nymphalis antiopa  (Mourning Cloak): 5
4. Celastrina ladon echo (Echo Blue): 3
5. Pieris napi  (Gray-Veined White): 1 (female-probably earliest ever)
6. Incisalia augustinus iroides (Western Brown Elfin): 1 
7. Erynnis propertius (Propertius Dusky-Wing): 1 
8. Colias eurytheme (Orange Sulphur or Alfalfa Butterfly): 1

Shapiro worries about the drought. On Tuesday, Jan. 28, he recorded: "Today was the 52nd and last consecutive day with no rain in winter--a record probably never to be equaled in any of our lifetimes (I hope)."

Meanwhile, his other nine study sites in the Central Valley await him. They are all over the map, just as he is. As he says on his website: "Ranging from the Sacramento River delta, through the Sacramento Valley and Sierra Nevada mountains, to the high desert of the western Great Basin, fixed routes at ten sites have been surveyed at approximately two-week intervals since as early as 1972. The sites represent the great biological, geological, and climatological diversity of central California."

If you're lucky enough to accompany him on a survey, you'll hear him point out butterflies as excitedly as a winner yells "Bingo! Over here! Over here!"