In California, you can observe 14 different species of hummingbirds. But most of them are migrating. Only a few species are found year-round in the southern part of the state. One of these is the shimmering, beautiful "Anna's hummingbird". It is a small hummingbird, about four inches (10 cm) long which can weigh as little as 0.1 to 0.2 oz . The species is the only one with a red crown in North America and therefore reasonably easy to identify. It has a red, iridescent throat which changes the color with the angle of the light. Anna's hummingbird subsists mainly on nectar but supplements it with insects, arthropods caught in flight, and sap from trees. During flight, it can generate an electrostatic charge that causes pollen to get stuck on the bill and head. When it then flies to the next flower, it helps with pollination. Unusually (for hummingbirds), the male sings during the courtship of the female. The nest is only 4-5 cm large, well camouflaged with lichens that are held together with cobwebs. The species traditionally nested only here, in Southern California and in Baja California, Mexico, but has expanded north along the West Coast since the 1960s, possibly with the help of humans through recently introduced trees and plants and access to nectar feeders in gardens.