Warbler Guy, which warbler species are the initial ones that return to the San Francisco Bay in spring? Are migrating warblers returning now?
Haley, those are excellent questions.
The short answer is Orange-crowned Warbler is the typical, initial wood-warbler species to appear annually by February as a true, returning migrant among the nine SF Bay Area counties.
The true, arriving migrants that settle to nest here may join a small number that appear to “over-winter” in the SF Bay Area. (It’s also possible the “over-wintering” individuals leave during spring and seek other breeding ground territory.
Next on the landscape as arriving migrant wood-warblers here: Common Yellowthroat and Wilson’s Warbler appear by no later than later March (or, if late, early April) annually. Soon after, the initial Black-throated Gray and Hermit Warbler nesters arrive. (Note the latter four noted above sometimes, also, are detected as “over-wintering” individuals, especially during Christmas Bird Count surveys that occur throughout the holiday season period of late December – early January, annually, in the SF Bay Area.
A good source for noting the “Arrival Times” of northern CA wood-warbler species: Go to the pulldown menu at my web site (WarblerWatch.com) and choose “Bird Arrival Times” at the “Birding Links” pulldown menu option at the top of the home page for WarblerWatch.com
In February annually, Orange-crowned Warbler individuals arrive as the earliest wood-warbler migrant…….and they join a few over-wintering individuals……though it’s possible the latter may leave to nest elsewhere (See range map, below).
(Orange-crowned Warbler, above….courtesy of Cornell Lab of Ornithology)
A far larger pulse of this common nester throughout n. CA arrives on breeding grounds by March.
Interestingly, among all wood-warblers to complete their nesting cycle early, this ground-nesting one often does so….I’ve walked forested areas where hearing their song is a daily experience. Then, by mid-May, I never hear their trilling lyricism until I visit the higher altitudes in the state (such as the Sierra Madres mountain range three hours east of Marin County where I live and host the majority of my n. CA birding tours as a guide.
One amazing aspect of Orange-crowned Warblers’ behavior occurs post-breeding. Upon leaving a nesting area, many do not migrate south, but instead move to higher altitudes, including foothill areas east of Marin Co. and as high as 6,000+ feet. Bird banders have noticed these movements by recapturing banded individuals in the Sierra that were initially temporarily captured in nets in SF Bay Area counties, including Marin Co.
At the higher altitudes where periodic summer rainstorms occur (especially in the afternoon), larger abundance of insect fauna exist as prey base for Orange-crowned. By August and beyond into autumn, it’s thought these individual eventually migrate south to s. CA and as far as s. Mexico and portions of Belize (adjacent to Mexico).
My web site — warblerwatch.com — is “enabled” but I am not able to “upgrade” it…..I’m trying to eliminate ads at my web site.
I sent the following message via the “help forum” a moment ago as backup to this one:
Please note: For 8 weeks with your kind help, a solution is STILL not happening for me to upgrade my web site so that I can eliminate ads. I’ve tried. You have tried. But no one who has suggested remedies from your team has been able to help me. The problem remains that no one has told me how to send an attachment to show my situation. An attachment would show you a screenshot of the screen I encounter where the problem occurs. Here’s where the problem occurs and I’ll describe it because this “Contact Us” area has no ability to send an attachment: the two-year payment screen is present. I choose it. I add all my essential information. All is perfect. But the screen never gets past “thinking” as it states a recalculation of how much I owe occurs…..and the final ability to click on “submit” never occurs. Solution?