Danaus gilippus

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.

Danaus plexippus

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.