Warbler Guy, which migrating warbler arrives first on the East Coast? Which warbler arrival shall I expect on the West Coast? Warbler migration has begun?

Lori, those are great questions.

The brief answer is look for the following warblers to initially appear as true returning migrants on the East Coast from the Mid-Atlantic north:

- Louisiana Waterthrush
- Palm Warbler
- Common Yellowthroat
- Yellow-rumped Warbler

For the West Coast, it's even more simplified:

- Orange-crowned Warbler (photo shown here) is often the most common returning nesting species, typically arriving by late February to early March, if you're in the San Francisco Bay Area where I live.

March 6 is the mean annual arrival date for this species on the coast in W. Marin Co. at the Palomarin (near Bolinas) bird banding station, based on 1967-1989 records. The earliest return date in this span is 2/27 and 3/16 was the latest.

Palm, Wilson's, and Yellow Warbler may also be early returnees on the West Coast, though it's challenging to definitively determine if sightings of these species are true migrants or "over-wintering" individuals.

Some Orange-crowned individuals in the Bay Area also may "over-winter," as Christmas Bird Count surveys in the San Francisco Bay Area often record this species and rare to periodic reports for this species persist throughout the winter during most years from Bay Area counties. In this case, if I hear an associated Orange-crowned song in February or March, then I usually deem the aria a returning migrant individual.

Happy birding, Daniel
danieledelstein at att dot net
warblerwatch dot com

Warbler Guy, why does American Redstart occur in California more often than most other so-called "East Coast" warblers? Is American Redstart a vagrant on the West Coast?

Excellent question, Joey (in Santa Monica).

Fact is, American Redstart is not always a vagrant in California when detected during the spring and late summer/fall.

That's because its far western home range into Alaska places it in the pathway of where some individuals may migrate up and down the West Coast.

Equally important, a northern California breeding population in the farthest region of the state has occurred in the past.

As a result, it's plausible to suggest annual breeders in this area could be southward migrating individuals that California birders detect from August through November annually, for example, in the outer point of Point Reyes National Seashore in Marin County or at Bodega Head in Sonoma County.

That written, it's ALSO possible some Midwestern and East Coast American Redstarts are seen in California. The species is abundant and locally common throughout much of its range, so, given the plethora of newborns each year, it's possible some become disoriented as vagrants spotted on the West Coast.

In summary, it's challenging to decisively determine the origin of an American Redstart observed from central to southern California. An observer would need to employ bird banding data and recapture a previously banded individual to find out its pathway of dispersion and/or migration.