It is partly correct to say that Anna's Hummingbirds do not migrate, but for
the species as a whole, this is an over simplification. From northern
California to British Columbia this species is non-migratory. There may be some
movement from higher to lower elevation in the fall as food supllies dwindle
and they may wander post-breeding, although how far they wander is unclear. It
could be a few miles for some individuals or just to the nexxt neighborhood.
Juveniles may disperse a greater distance but their dispersal, and that of
adults, may not follow any patern, but simply be the result of individual
variation. So, in Oregon, it is correct to say that they are non-migratory.
In the southern half of California, migratory movements are not well understood
and seem to vary from population to population. Some remain in an area
throughput the year. Many turn up at higher elevation in western Arizona after
breeding and apparently have left breeding areas in southern California. Still
other birds seem to move northward to central latitudes in California from
southern California. Details of these variuos movements are not well understood
or well-defined.
Dan Gleason
Owner, Wild Birds Unlimited of Eugene
Ornithology Instructor, University of Oregon
dan-gleason@xxxxxxxxxxx
541-953-4726
On Feb 4, 2016, at 9:55 PM, David Bailey <davidcbaileyoregon@xxxxxxxxx> wrote:
Tim R,
Conventional wisdom would assert that Anna's Hummingbirds do not migrate.
That has been my observation in NW Oregon. You have probably considered that
too. Since Anna's will nest early in the year (and midwinter), I suppose
early fledgling could account for an influx in the numbers at a specific
feeder or area. Could you shed some light on your statement of Anna's
Hummingbird migration. Perhaps I have been in the dark about this.
Respectfully,
David
David C. Bailey
Seaside, Oregon
Just one male Anna's visiting my one feeder currently.
