Community-level studies of relationships between hummingbirds and nectar plants have revealed geographic differences. Tropical sites, for example, usually have greater hummingbird and nectar plant diversity than temperate sites, and their flowers provide greater sugar rewards, on average. We investigated plant use by hummingbirds in the Chiricahua Mountains, a temperate site (32 degrees N) where 5 hummingbird species occur as common breeders or migrants between April and September. At our study sites hummingbirds visited 9 plant species in the foothills, and an additional 11 species at higher elevations. Fourteen of these, from 7 plant families, have red tubular or trumpet-shaped flowers, suggesting adaptation for hummingbird pollination. We measured nectar production for 10 of the hummingbird-adapted species, and identified a group of 8 convergent species (from 5 families) and 2 outlier species. In the former group (consisting of species of Penstemon, Castilleja, Aquilegia, Fouquieria, Salvia, and Silene), mean daily production was 2.3 mg sugar/flower (coefficient of variation: 35 %). This sample converged on the range of values typical for U.S. hummingbird plants. However, two taxa of claret cup cactus (Echinocereus Section Triglochidiatus) with large flowers offered 12-14 times as much nectar as the hummingbirds’ typical resources. Concentrations of solutes (assumed to be sugars) in nectar were similar in all 10 species, including the cacti (mean: 0.32 mg solutes/mg solution; coefficient of variation: 19 %).

Key words: Chiricahua Mountains, hummingbird plants, nectar production