Hymenopteran with striped abdomen and hairy orange head and thorax. Fairly common on willow flowers here; at least 20 (and probably many more) foraging in this willow. Ca 11 mm long. On unidentified, flowering Salix sp. with black floral scales and ca 1 cm long, emerging leaves, one of the few riparian shrubs in this area not top-killed in last September's fire. Gentle SW-sloping streambank, 1 m from stream edge, with some live top growth remaining of Rosa woodsii, Prunus virginiana, Ribes setosum, and Alnus incana. Understory with Lepidium chalepense and Descurainia (sophia?). Mid-afternoon, sunny, light breeze, 69 F.
Elevation ca 4000 feet. Disturbed, shrubby riparian corridor on stream restoration site within a patchwork of native and non-native grassland.