Wednesday, December 17, 2008
Is the American Redstart a vagrant in the western USA?
Thanks for the question Lori Anne (in Seattle).
Although many eminent, well-respected authors suggest, for example, a California sighting of American Redstart deserves a “vagrant” status designation*, I beg to differ.
(* = vagrant status applies to a bird species that is found far from its typical breeding or non-breeding area.)
That’s because my research suggests small populations of this species periodically to annually nest in small numbers in n.w. CA. In addition, other breeding range individuals occur as far west as s.w. Idaho, Oregon, and Washington.
As a result, I believe it’s more appropriate to refer to autumn and winter sightings of this species in northern California as “casual visitors.” That term qualifies a bird species’ status as one that is slightly removed geographically from where it is expected to be seen in either breeding or non-breeding range.
Ultimately, it’s possible a Bay Area (e.g., Point Reyes National Seashore) sighting of this species could be an individual that spent the breeding season in farther north latitudes, such as the aforementioned n.w. CA area (or Alaska, more probably, where populations in greater abundance breed).
In any event, the entire species of American Redstart are thought to be locally abundant in much of their breeding range, especially if suitable habitat remains. However, it should be noted that populations have declined where forests have been fragmented by development and where urbanization has replaced habitat.