Anna's hummingbirds and ruby chalice clarkia

The hillsides around Tiburon hold their color differently in late spring. Where winter rains once darkened the soil, patches of ruby chalice clarkia now bloom in clusters of deep pink, their four-petaled flowers catching the morning light. The Douglas-fir trees show fresh green needle tips, and the poison oak leaves have settled into their glossy three-leaflet patterns. This is the season when the landscape and its smallest aerial residents move in careful synchrony.

Anna's Hummingbirds are deep into their nesting season now, the males' territorial calls sharp and frequent from the coyotebrush and willow branches. A female hovers at the clarkia blooms, her needle-thin bill probing each flower for nectar. She moves methodically from bloom to bloom, her wings beating so rapidly they blur into transparency. The timing is precise. The clarkia flowers produce their richest nectar in the morning hours, and the hummingbirds have learned this schedule. As she feeds, pollen grains stick to the feathers around her bill and throat, pale yellow dust that she will carry to the next patch of flowers.

The relationship runs deeper than simple feeding. Ruby chalice clarkia evolved alongside hummingbirds, its deep pink petals and tubular flower shape perfectly matched to the birds' feeding behavior. The flower's stamens extend just far enough that a hummingbird must push past them to reach the nectar, ensuring pollen transfer. Other pollinators visit these flowers, bees and butterflies among them, but the hummingbird's hovering flight and long bill make it the most effective pollinator for this particular plant. The female Anna's Hummingbird needs this concentrated energy source now more than ever. She is building a nest, a tiny cup of plant fibers and spider silk bound together and camouflaged with lichen, hidden in the fork of a willow branch. Each day she adds more material, and each day she must fuel both her own metabolism and the development of her eggs.

The clarkia blooms will continue for several more weeks, their peak abundance timed to support not just the hummingbirds' nesting season but the broader community of pollinators that emerge in late spring. Native bees work the flowers in the afternoon heat, and Gray Buckeye butterflies visit when the light begins to soften toward evening. The pitted onion and Ithuriel's Spear add their own nectar sources to this seasonal feast, their purple and blue flowers creating a mosaic across the grasslands. Listen for the hummingbird's call, a sharp chip that cuts through the morning air, often repeated in rapid succession when she encounters another bird near her feeding territory. The sound carries farther than you might expect from such a small bird, a declaration that these particular flowers, this particular patch of hillside, are spoken for.