This very pale-colored Ringlet is still abundant in foothill woodland, breeding in grassland intermittently up to 5000', but seems to be in precipitous decline in the Sacramento Valley where it went extinct at North Sacramento and is "on the edge" in Rancho Cordova. There are two very different-looking broods. The spring brood (March-May) is somewhat silvery above and the basal half of the hindwing is intemnsely melanized below (for thermoregulation, we assume).

A subtropical relative of the Monarch, the Queen breeds on Milkweeds in the desert Southwest including southeastern California, and very rarely strays northward. On August 23, 2008 a male in excellent condition was observed as it nectared on Rabbitbrush, Chrysothamnus nauseosus, at Donner. My previous northernmost record was at Topaz Lake, Mono Co., 50 miles SSE of Donner. It would not be terribly surprising for it to turn up again.

This very familiar species requires no description! It is recorded at all the sites on our transect, even though there are no host plants above 6000' in the I-80 corridor. The records at Donner and Castle reflect migration across the Sierra Nevada in both directions, though late-season west-bound migrants are most often recorded. Breeding has been observed at all the sites from Lang Crossing down. The Monarch overwinters on the central coast and moves inland, typically in early March.

Common in both the Coast Range and Sierra foothills, to 5000'; absent at Donner and Castle Peak; common in Sierra Valley; absent from the Sacramento Valley and Suisun. Populations in the Coast Range have mostly black larvae with orange markings and little if any white. Populations from the lower foothills (beginning at Sailor Bar, Fair Oaks, Sacramento Co.) eastward have strong lengthwise white larval striping.

This colonial species is divided into numerous taxonomic subspecies. Since none of our populations belongs to a legally-protected subspecies, we will ignore the trinomials here. Much more local than E. chalcedona, usually flying earlier, and in our area easily told from it by the rounded wings, reduced black above, lack of white spots on abdomen, and partly-black antennal club. Many populations occur on serpentine. On our transect the only population west of the Sierran crest is at Washington.

The Buckeye occurs at all our sites but is non-resident above 5000'. At Lang it has overwintered successfully, but clearly not every year. It is not certain that it ever overwinters at Sierra Valley. In some years, e.g. 2005, there are massive waves of immigrants in early summer. We do not know where they come from. In such years the peak density may be reached in midsummer, as Buckeye reproduction temporarily outstrips the capacity of natural enemies to control the population. The Buckeye breeds continuously in warm weather. Usually the population peaks in autumn.

A characteristic riparian species from sea level to at least 8000', flying along willow-lined streams and perching territorially. It appears to mimic the inedible California Sister, with which it often occurs. Adults visit California Buckeye, Buttonbush, Yerba Santa and a variety of other flowers, and males are enthusiastic puddlers.

A very distinctive and charismatic butterfly, best known for its conspicuous activity in late winter, flying and acting territorial before any trees have leafed out or any wildflowers are active. It hibernates as an adult. In the Sacramento Valley there appears to be only one brood (in spring); the resulting adults migrate upslope and breed in the mountains. There is a reverse downslope migration by the next generation, in late September-October.

Along with the Painted Lady, this is a mass migrant that makes news at irregular intervals by tying up traffic! The "Tortie" overwinters as an adult and can sometimes be seen sunning itself in midwinter on mild days. It is generally common in foothill canyons in late winter, ovipositing on the young, tender growth of various species of Wild Lilac (Ceanothus). The spiny, black-marked-with-yellow larvae feed gregariously, without a web, and in big years can defoliate whole stands of the plants.

Recorded from most sites on the transect, but this is an altitudinal migrant that spends the winter as an adult near sea level, breeds there in spring, then shifts to the Sierra (particularly the East slope) for summer breeding before returning west in autumn. Fresh adults are often common on Coyotemint at tree-line on Castle Peak, even though there are no host plants that high. They were apparently born and bred on stinging nettle (Urtica holosericea) around Truckee and Loyalton!