Donna (in Tacoma, WA):

Nice question.

Typically, the female (who chooses the male partner) in your area incubates eggs for 10 or 11 days {Bigglestone, H. C. (1913). A study of the nesting behavior of the Yellow Warbler (Dendroica aestiva aestiva). Wilson Bulletin 25:49-67.).

Newborns generally often leave the nest 8–10 days after hatching, but this amount of days may vary by latitude……Washington (your location) is somewhat on par with Manitoba’s latitude where young left the nest an average 8.2 days after hatching (among 12 observed subjects) {Briskie, J. V. (1995). Nesting biology of the Yellow Warbler at the northern limit of its range. Journal of Field Ornithology 66:531-543.}

Of course, exceptions happen….and more details are written about this subject at several sources. One of the easiest places to read more is at: allaboutbirds.org….or the classic, excellent The Birder’s Handbook: A Field Guide to the Natural History of North American Birds (Paul Ehrlich, David S. Dobkin, Darryl Wheye, Simon & Schuster, Inc.,1988). (See below image of the book’s cover.)

Meanwhile, please feel free to visit my web site: WarblerWatch.com where my bird survey and bird classes are noted……….and, I’m happy to note: I’m glad to prepare for two upcoming birding tours: 1) I’ll guide four birders from San Francisco to Bodega Bay (Sonoma County, CA) at low tide, given some shorebird family members are already back for the non-breeding season here in northern/central California where I regularly lead outings…..and/or some of the individuals we’ll see (e.g., Short-billed Dowitcher, Least Sandpiper, and several other shorebird species are merely transients, but forage at ample “wayside” mudflats amid Bodega Bay at low tide.). An night-time “owl prowl” to the same area features a Coastal Redwood forest where four to six owl species are nesting, with the resident Northern Spotted Owl subspecies present and, as you can imagine, a highlight to hear (and sometimes see) (We leave promptly after detecting it and never use playback; we do not wish to harass the adults or newborns at this undisclosed site that seems to be a perennial nesting activity center.)

Daniel Edelstein, M.S.

Avian Biologist & Certified Wildlife Biologist Asc. & Birding Guide
based in the San Francisco Bay area (Novato, CA)

415-382-1827 (office)

415-246-5404 (iPhone)

WarblerWatch.com (features my resume)

WarblerWatch.blogspot.com (This blog’s #)