Allen's hummingbird is a small bird often difficult to distinguish from rufous hummingbirds. Mature adults are only 3 to 3.5 in (76 to 89 mm) in length. Immature Allen's hummingbirds are nearly identical to the female rufous hummingbird. Their breeding location runs along a narrow strip of coastal California and southern Oregon. Like all hummingbirds, the Allen’s Hummingbird has a high metabolic rate and must feed frequently. In addition to sipping nectar from flowers, they love catching flying insects and plucking them out from leaves. Allen's hummingbird's estimated global breeding population is 1.7 million, all of which breed in California and Oregon, with 96% wintering in Mexico. The continued survival of the species is problematic. Between 1970 and 2014 their populations have declined by 83%. If current rates of decline continue, Allen’s Hummingbirds will lose another half of their remaining population within the next 17 years. Allen's Hummingbirds may not be as adapted to urban environments as other species of hummingbirds and their coastal habitats continue to be under intense pressure from habitat loss due to land development. However, hummingbird feeders, eucalyptus, and other nonnative plants may provide additional nectar resources that could partially offset these problems. “Allen’s Hummingbird and Cactus Flowers,” is a digital painting and photo composite derived from original sources.