This hummingbird male has a black ‘helmet' over its entire head extending down the back and sides of the neck and chin. It is distinguished by a deep royal blue band just blow the chin extending to both sides of the lower neck. Below the blue band is a white collar in the male, as pictured. The body is olive green done the back and sides, with a mottled white breast. The female lacks the dark helmet and bands. The front of the neck has lines of small spots in several vertical bands...4th photo above.
These hummingbirds have just arrived from central Mexico and the Gulf Coast into southern Nevada, first seen in mid-April. They frequent the feeders in our garden, which is in an urban area in the arid Mojave Desert. The surrounding habitat is covered with pine trees,various shrubbery, and grassy areas.
Per the reference cited below...in cold weather, a Black-chinned Hummingbird may ingest three times its body weight in nectar in one day. Their nest can expand as nestlings grow. The spider and insect silk holding it together stretches and allows the nest to grow along with the growing chicks. These birds are very adaptable, and live in a number of different habitats including mountain foothills, arid regions, costal habitats and riparian areas.