A total of 15 sightings was reported to me in the winter of 1975-1976. By compiling reports from 1975 until the present, I have seen a distinct pattern emerge. A few Black-chins are reported in fall migration. There have been sporadic reports of this species through the fall until late October. At that time, they begin to concentrate at feeders for a winter residence which lasts in some cases into mid-April.
Some birds remain constantly at one location.
These patterns seem related to the severity of the winter and the availability of natural foods but there is no one single factor which influences these birds. In anyone season, there are some birds which fit into each category. The majority of reports are of juvenile males. Females may be overlooked. To better evaluate the population of all species of wintering hummingbirds, I initiated a program of banding and color-marking in 1979.