Lepidoptera (butterflies, moths) of Albany Hill

Jerry A. Powell (Essig Museum of Entomology, University of California, Berkeley)

Robert L. Langston (Kensington, CA)

November 1999; edited 2009

The following list summarizes observations of Lepidoptera (moths and butterflies) at Albany Hill, Alameda Co., California, during 1995-1999. Data originate from about 75 daytime and crepuscular visits of 0.5 to 3.5 hrs, in all months of the year. All of the butterfly species and some of the moths were recorded by RLL, most of the moth species and their larval host plants by JAP.

A total of 145 species is recorded (30 butterflies, 115 moths), a modest number considering the extent and diversity of the flora. However, many of the potential larval host plants may be present in too small patches to support populations of larger moths or butterflies. Nonetheless, we were surprised that colonies of some of the species survive in a small area that has been surrounded by urban development for many decades, including some rare ones in the East Bay region, as annotated below. Moreover, the inventory is incomplete. A more comprehensive census would be accomplished by trapping moths attracted to ultraviolet lights. In a habitat of this size, however, such survey would attract an unknown proportion of species from surrounding areas.

Larval collections are indicated by date-based JAP lot numbers (e.g. 95C37 = 1995, March, 37th collection). Larval foods of most of the other species are documented in other populations. Host plants are recorded at Albany Hill for 75 species (65% of the moths, 52% of the total); the rest were observed as adults only. Of the total, 15, possibly 18 (13%), are non-native exotics in California. At least six of the butterflies and several of the moths are vagrants here and/or depend upon plants in subtending urban and weedy areas.

Rare and unusual species. No species is formally designated as endangered or threatened, but several were surprise discoveries, rare or unknown species for this region.

Greya reticulata (Riley). — We found this small moth abundant in late March and early April, in 1995 and 1998, using buds of Sanicula crassicaulis for oviposition. After its original description from Los Angeles and Alameda, reticulata was `lost’ for nearly a century prior to its rediscovery in Santa Clara Co. in the 1960s, where its larvae feed on Osmorrhiza. Several colonies are known, including San Bruno Mt., San Mateo Co., but there had been no record in the East Bay since the 1880s. Sanicula was not previously known to be a larval host.

Perittia cygnodiella (Busck). — Larval mines were abundant on Symphoricarpos in 1995. This species was described from British Columbia and is widespread in the Pacific States but is rare in collections because the adults are inconspicuous, diurnal, and fly in early spring. Larvae had been reared only at San Bruno Mountain previously, and we had no prior record of the species in the East Bay area.

Elachista gildorella Kaila. — Two individuals of this previously undescribed, grass-mining species were taken at the same spot on the northwest slope of the hill in April 1995 and 1998. This species is known from only two other localities, San Bruno Mountain and Point Reyes. Elachista marachella Kaila. — Several specimens of a second undescribed species were collected on the north slope of Albany Hill in March, April, and June. Larvae were found mining Ehrharta erecta in Strawberry Canyon on the UC Berkeley campus in 1978-85. This introduced grass also occurs on Albany Hill, but marachella is a member of a complex of closely related Californian species, and native grasses presumably serve as larval hosts.

Epinotia lomonana (Kearfott).– This species also is rarely seen, because the adults fly in late fall. It was recorded in Orinda in 1961 and once as a vagrant in urban Berkeley. The larvae feed on native Prunus, and unexpectedly, we found a relict colony on the patch of P. subcordata at Albany Hill.

Acleris keiferi Powell. — Larvae of this species were found on Rosa californica. A. keiferi was described 35 years ago from specimens collected in San Francisco in the 1920s and 1930s, and there were specimens from Berkeley collected in 1931 and Bear Creek (now at the bottom of Briones Reservoir) in 1957. It remained rare in the East Bay area until 1993 when we discovered a colony on Brooks Island, also feeding on Rosa californica. Elsewhere the larvae have been found on Rubus and Fragaria.

Oidaematophorus occidentalis Walsingham — This species, which we have not seen fromthe Bay Area previously, was originally described from Colusa and Shasta counties. At Albany Hill the larvae are suspected to feed on Wyethia angustifolia and/or Grindelia hirsutula, based on records in British Columbia.

Battus philenor (L.) (Pipe Vine Swallowtail). — Individuals were observed on at least six dates, flying in woods and hilltopping. The larval host plant, Aristolochia, is not known here but perhaps overlooked? Individuals fly long distances from the larval colonies, but the nearest known colony is Brooks Island-Pt. Richmond; hence this frequency of vagrants would be surprising.

Pieris napi (L.) (Veined White).– Single females were flying near Cerrito Creek, in 1996and 1997, posing a mystery. Populations are known in the Berkeley Hills, but individuals of thisspecies rarely wander far from their shaded habitat where Cardamine grows. This plant is present in the Albany Hill flora, but it is surprising if the colony of milkmaids is large enough to support a resident population of P. napi.

Danaus plexippus (L.) (Monarch).– There has been an overwintering aggregation of the Monarch butterfly in the Eucalyptus grove at the top of Albany Hill for many years. In recent years numbers have consistently ranged in the hundreds, perhaps more than 1,000. They were particularly conspicuous in December 1997. There is an aggregation site at the Richmond Field Station and others in Alameda and San Leandro, also in Eucalyptus. No larval breeding site is known in coastal parts of the East Bay counties.