Baskett Butte: Baskett Slough National Wildlife Refuge

 

 

Location: Polk County west of Salem.

Owner/manager: US Fish and Wildlife Service.

Directions: From the east at Interstate 5 exit 253 (Salem): Go west on Highway 22 through downtown Salem seventeen miles and make a hard right on Colville Road which is three miles beyond the Highway 99W intersection. (Note that Business 99E going southwest from Interstate 5 exit 260A also connects with Highway 22 in Salem and is slightly shorter for those coming from the north). Follow Colville Road one and one half of a mile east and then one quarter of a mile north to a parking lot where Colville Road bends east again.

Free. No camping. No pets on trails or viewing areas (they may be walked at the information kiosk).

 

Baskett Slough National Wildlife Refuge is ten miles west of Oregon’s capitol along Highway 22 heading to the coast. Logging trucks frequently barrel down this busy stretch of highway as well as the rusty cars of the restless natives bound for – where else? - the beach. High on a hill above this all a tiny butterfly renews its life cycle each spring amid grasses and lupines.

The Fender’s Blue Plebejus icarioides fenderi is a subspecies of the Boisduval’s blue. Boisduval’s blues are found throughout the mountainous west, almost wherever there are lupines. Their wingspans are short, their lives brief but fascinating and their taxonomy complex. The larva of Boisduval’s blues feed exclusively on lupines, and sometimes one group of Boisduval’s blues will become largely associated with one variety of lupine, hence the continuing taxonomic controversies. The Fender’s blue is such a case. The lupine its larva have chosen to dine upon, Kincaid’s lupine Lupinus sulphureus ssp. Kincaidii, is itself a rare plant, hence the Fender’s blue is also a rare butterfly.

There is one generation of Fender’s blues each year. They are born in mid-spring, feed on their host plant until early summer, hibernate as caterpillars from mid-summer to late winter, feed once again for perhaps a month before briefly entering a pupal stage and finally become adult butterflies that quickly reproduce and die. The long dormant stage of the caterpillar is unusual. Most butterflies in temperate climates survive the winter as eggs or pupa, or migrate as Monarchs do. Also somewhat unusual is the short time Fender’s blues spend as adults, not much more than a couple of weeks on average, making dispersion to other sites problematic.

Adult Fender’s blues are relatively difficult butterflies to observe. They are either completely camouflaged or a blur of motion. The upper surface of the wings of the males is an iridescent blue with a black border while the females display a dull copper grey. When motionless Fender’s blues usually close their wings, the undersides of which are a chalky silver with a bit of tan and some small black spots arranged in an arc. These black spots have white halos. The size of the black spots and their halos on the underside of the wings of the males is what visually distinguishes the Fender’s blue from other subspecies of the Boisduval’s blue. In the Fender’s blue these black spots are relatively small and have fine white halos.

The biologist Ralph Macy, best known for a book on eastern butterflies, first described the Fender’s blue in 1931. He simply noted that for several years he had observed ‘a small colony of large Blues flying about an isolated patch of Lnpiinis (sic) on a hill-side six miles south-west of McMinnville, Oregon’. (Macy,R.W. 1931. A new Oregon butterfly (Lepidoptera, Lycaenidae). Entomological News Volume 42. p1). The species of lupine was not described. No Fender’s blues were collected after the 1930s and with the large scale disappearance of native grasslands within the Willamette Valley the species was presumed extirpated by the time of the passage of the Endangered Species Act. In 1989 the Fender blue was rediscovered in an unexpected place by Paul Hammond an entomologist at Oregon State University. Previous attempts to find the Fender’s blue had focused on the more common lupines in the vicinity of the original discovery, most of which have a purple or blue inflorescence. Paul Hammond found a group of Fender’s blues near Corvallis using as host plants the rare yellow and violet Kincaid’s lupine Lupinus oreganus. Subsequently two other lupine species have also been found to rarely host the Fender’s blue larva but in general there is a very strong association between this butterfly and Kincaid’s lupine. The upland prairie at Baskett Butte within Baskett Slough National Wildlife Refuge is somewhat of an exception that proves the rule, here some hybridization between Kincaid’s lupine and spurred lupine has occurred (Liston, Aaron, Kimberly St. Hillaire, and Mark V. Wilson. 1995. Genetic Diversity In Populations of Kincaid’s lupine, host plant of Fender’s blue butterfly. MADROÑO, Vol. 42, No. 3, pp. 309-322, 1995).

The taxonomy of Kincaid’s lupine is unsettled. It is a member of the Fabaceae, the pea family, and regarded as either its own species Lupinus oreganus or a variety or subspecies of Lupinus sulphureus. Within the state of Oregon it is distinctive enough to be readily identified by its low growth habit, yellow and violet unbranched inflorescence and a upper petal (banner) that is ruffled and curved backwards (reflexed). Lupine flowers are highly adapted to accommodate the bodies of bees with a minimal production of nectar and there may very well be some significance to the exact shape of the flower of a particular lupine species and the bees that frequent its habitat.

There are two distinct geographic groups of Kincaid’s lupine, one along the western edge of the Willamette Valley and the other about fifty miles to the south in the Umpqua Valley. The habitat for these two groups is different. The southern group resides on edge habitat that is often considerably shaded such as roadsides and serpentine barrens. The northern group is typically found on open upland prairie that for western Oregon has relatively dry soil. Only the northern group hosts the Fender’s blue.

Kincaid’s lupine readily spreads by rhizomes and is often found in tight clusters. This serves the needs of the Fender’s blue larva well as they can drop to the relative protection of the base of the plant when disturbed. All parts of the plant are fair game for the larva which feed first on leaves, then flowers and finally seedpods.

Several other subspecies of Boisduval’s blues have a mutualistic association with ants, or more precisely a myrmecophily. This aspect of the life cycle of the Fender’s blue has not been studied in depth but the description of this butterfly in the Final Rule for its endangered species status noted a possible association with Argentine ants (Federal Register Vol. 65, No. 16 /Tuesday, January 25, 2000 /Rules and Regulations. p3877). Larva of other Boisduval’s blues produce a ‘honeydew’ secretion that attracts ants which in turn protect the larva from egg laying parasites.

The adult Fender’s blue requires nectar rich flowers to feed upon. Lupines are relatively poor in nectar as are many exotic species that have taken up residence in the upland prairie habitat of the Fender’s blue and Kincaid’s lupine. The survival prospects of the Fender’s blue appear to increase in prairie habitat that includes a high abundance of relatively nectar rich native vegetation. (Wilson, MV, PC Hammond, CB Schultz. 1997. The Interdependence of native plants and Fender’s Blue butterfly. Native Plant Society of Oregon). Such vegetation includes various wild onions, lilies, flax and checkermallows.

One nectar rich native present at Baskett Butte is the Willamette daisy Erigeron decumbens. The Willamette daisy is a perennial composite which has white to light blue outer ray florets and central disc florets that are yellow orange. Established plants can often be found growing in tight clumps four to five feet tall. The Willamette daisy has stems that typically have withered lower leaves and when unsupported a tendency to fall over on the ground, hence the ‘decumbens’ specific epithet. The latter feature of this plant probably contributes to its rarity since its seeds have less of a chance to disperse widely in the wind. The Willamette daisy is typically a plant of wet prairie and wetlands but at Baskett Butte it is found in upland prairie, where its numbers have steadily declined. (Demographic Analysis of Erigeron decumbens var. decumbens, An Endangered plant species of the Willamette Valley, Oregon. 1999. Clark, Deborah L. UFWS Western Oregon NWR Refuge Complex Order No. 1448-13590-9-M047A). The Willamette daisy was widely collected in the 19th century but in the mid-20th century was presumed extirpated until it was rediscovered in 1980 at two locations. Of the Oregon rare species trifecta at Baskett Butte – Kincaid’s lupine, the Fender’s blue and the Willamette daisy – the latter is probably the most endangered.

Baskett Slough NWR was established as habitat for waterfowl and the dusky Canada goose in particular. Baskett Butte to the east of the wetlands did not become a management focus here until the 1990s when it was discovered that it held the world’s largest population of the Fender’s blue. By then its upland prairie habitat was heavily overgrown with shrubby vegetation. Since then considerable effort and experimentation has gone into recreating the upland prairie and savanna habitat here. The native grasses that form the foundation of the upland prairie here such as Roemer’s fescue Festuca roemerii and California oatgrass Danthonia californica are returning in greater abundance.

When planning a visit to Baskett Butte so as to best catch a glimpse of the Fender’s blue it is all a matter of when to arrive, and the best time to arrive is the spring. A walk up the hill on a sunny day in May is likely to reveal a glimpse of at least a few of these butterflies darting about. In addition to the Fender’s blues the oaks here often harbor yellow and white crown sparrows and the grasses below them western meadowlarks. About halfway to the top the trail splits up. One trail loops to the north and goes through an area of Oregon white oak savanna. The grasses along parts of this trail are not too thick and often sway in the wind, revealing flashes of colorful flowers in their midst, an effect seldom seen in most gardens but often in the wild. The other shorter trail to the south continues to the top of the butte, where the ugly events of the outside world have managed to disturb the tranquility of an otherwise fine view. The viewing platform here is dedicated to Rich Guadagno, the former manager of the refuge from 1992 to 2000, who perished on board United Flight 93.

High on a hill in western Oregon amid grasses and lupines, sadness and beauty, a tiny butterfly renews its life cycle each spring.