Three views of a Silver Bee (Habropoda miserabilis) gathering nectar and pollen from Silver Dune Lupine (Lupinus chamissonis) in the Bodega Dunes on 15 April 2012. Silver Bees are important native pollinators in California and Oregon dune systems.
In the third photo (above), you can see the bright yellow pollen on the scopa of the bee's hindleg. A scopa is a tuft of dense hairs used for collecting and transporting pollen.
Silver Bees are relatively large (~15–20 mm long), solitary ground-nesting bees. Nesting occurs during the spring and early summer and can sometimes be gregarious (multiple burrows at one site). The females dig long burrows in the sand (~20" long, ending in a cell that lies about 8–11" below the surface). They provision the cell with pollen and nectar and then deposit a single egg. The larva hatches, grows, pupates and emerges (underground) as an adult in late summer/fall. The adult overwinters in the burrow and emerges the following spring.
Here's a photo of a Silver Bee hovering above the sand near a nest site (taken 2 May 2011). You can see the bee's shadow on the sand below. The bee's wings aren't visible because they were moving too fast for the camera. The fine-grained, light-colored sand was probably carried to the surface by a bee digging a burrow.
P.S. Forty-eight species of bees have been documented on Bodega Head. See the full list here.