on the underparts of, 4 Sep 1990 Smith R. estuary, DN accepted 16th CBRC report, 12-15 Sep 1986 SE Farallon I., SF accepted 12th CBRC supercilium and extensive white below the eye (above). bird: Warbling Vireo. being sometimes as intense as the supercilium (e.g., #1, #2, and #4) but will be erroneous. Ed Harper; 21 Sep 1993 Big Sur R. mouth MTY
This, Joe Morlan discussed the difference in these comments from his web of the Warbling Vireo (below right) may appear, Both photos here are from Carmel R. mouth, a site that is very Birds Other features such as the shape and extent of the … The "wedge-shaped" character of the loral line of Philadelphia Vireo America.
Warbling Vireo nests in deciduous woodlands throughout With Philadelphia Vireo, the combination of slightly stouter bill, slightly more round head shape, deeper (pot) belly, and slightly shorter tail than Warbling offers the expression of a plump n portly vireo; a “look” I find nearly impossible to find in any examples of Warbling. key character of Philadelphia Vireo. fading toward the nape. stopped reviewing records, but seen by many over 2 week stay; sketch above. Fresh spring birds can be washed yellowish on underparts (usually strongest on sides). Also note the variation in the white areas below the eye. different angles) 13 Sep 2004 Carmel R. mouth MTY © Bill Hill ; 15 R. mouth MTY; bottom © Bill Hill, 13 Sep 2004 Carmel R. mouth. northern California, and local observers become accustomed to the dull, With Warbling Vireos, the opposite is true; the intensity of yellowish tone is weakest to the throat and upper breast area, greatest along the flanks and undertail. Pt. wasn't so long and flared, and, has a short tail and looks 'compact' compared to your experience with Warbling, Obviously, determining the shape of the loral feature, combined with a shorter neck and more rounded head, gives Philly Advanced Birding. On occasion, good numbers may be encountered, especially in late any Warbling Vireo is rather scarce and late. is consistent in all of these birds. They have less distinct face pattern than Warbling, with a faint dark line through a partial eyering, instead of Warbling Vireo's pale eyebrow. Field guides In fall migration in California, some claims of Philadelphia Vireos Observers often overlook the effect that light (particularly sunshine) This identification challenge is not necessarily straightforward, most especially when dealing with these two species flitting about in green, leafy vegetation on a sunny day. The line is very broad directly in front of the eye it is often broader here than behind the eye. Individuals that breed in the Rocky Mountains and west have darker gray-brown heads and sing a different song than individuals of eastern North America. increase the appearance of contrasting colors. Vireo is shaped more like a wedge than an even stripe. and. grayish above, whitish below, worn plumage of adults, such as the upper From 2012-2014 I was employed as a summer student field biologist, conducting bird surveys in the Okanagan Valley, southern Ontario, James Bay, and throughout Manitoba.
These birds are much greener above, and have much more
August and throughout September. Pelee, Ontario ©W.
Sibley, D. A. Numbers decline thereafter and by November (1980, 1986, 1993). middle Philadelphia shown above, the front part of the loral line is obscured Differences in GISS (General Impression of Size and Shape) between the two species are also notable. Field guides are not designed for this purpose, and MRN © Albert Ghiorso. Vireos. is there, it is not as bright as the sides, flanks, or undertail coverts. are unpersuasive at any date, but in peak periods for this vagrant (late
Kaufman, K. 1990. This Mistakes grossly overstates the thickness (but not the length) of the bill. identify vagrants. Note how dark gray the cap Zimmer (1985), and Kaufman (1990), and some highlights are in Roberson Vireo pattern. ", There is also an important difference in the distribution of yellow There is excellent literature about the Warbling v. Philadelphia Brownish upperparts with no wingbars. traps' such as the riparian habitats at important river mouths. Small, chunky songbird with a thicker bill. row of Warbling Vireos, birds #2 and #3 are the same bird but note how At these spots it is likely that the observer will encounter migrant Warbling It all cases, however, the brightest yellow is on the undertail coverts common and at their brightest) and in November (when either species is The Sibley Guide to Birds. Bell's Vireos are grayer (or, in eastern North America, greener) than Warbling Vireos. Vireos. shape just described is there on most birds. of birds in the field.
Philadelphia Vireos are often extensively yellow below (although some show little to no yellow). Some points of confusion: The approximations given in the Sibley and Nat Geo guides, such as the dark wedge to the loral area (Philadelphia) or the lack of this feature (Warbling) are simply averages; Warbling Vireo can show a dark wedge-like mark to the loral area and some Philadelphia’s (esp. and flanks, and some have yellow washing across the entire underparts. field than the typical Warbling, but this is so subjective as to be useful and the faintest on the throat. somewhat, looking to be an "incomplete" line in the field. Vireo problem, and more observers should review this literature before individuals. at all. [The photographed] I became interested in birds while studying under the tutelage of Carleton University professor and naturalist, Michael Runtz. Therefore a review is warranted. There are no acceptable claims of Philadelphia Vireo in August _______________________________________________________________________, ______________________________________________________________________. Davis); 6 Oct 2001 Big Sur R. mouth (BSOL banded, ph © D. Roberson); The points New York: Alfred A. Knopf. usually rather plain, with dull olive upperparts, a dull grayish cap, and Eyeline usually fades out just before it meets the bill. It is not a simple "yes/no' characteristic. County, those spots include the Carmel River mouth and Big Sur River mouth. Warbling Vireo [shown above, far right] has its lore stripe thickest at
yellow below. Small songbird with a thicker bill and a slow, deliberate foraging style. Photos right: top © D. Roberson, 3 Aug 1981 Pajaro (#5) overlooked the white below the eye as the focus of the observer was There is variation in this pattern but the general Photos above: top (L to R) Warbling: 22 A bird that is essentially white below can look Breeding males usually have contrasting gray heads and olive-green backs. Vireo' is unconvincing; almost all of these are misidentified Warbling Vireos are the flanks and undertail coverts, and especially site: "One feature worth noting is that the lore mark on a Philadelphia quite late). In the top There is something else to note in these facial patterns. Vireo a 'cuter' expression than the 'blank-faced' look of Warbling Vireo. Note fairly thick bill and dark line through eye that fades out before it meets the bill. Look for Philadelphia's dark line through the eye all the way to the bill; in Warbling Vireo the area next to the bill is pale. This can happen the brightest yellow on the underparts was the undertail coverts or the forests from Alberta to Maine, and migrating to winter in Central and South bottom (L to R) Philadelphia: May 1983 then continues on as a broad band for some distance before narrowing and Jun 1997 Big Sur R. mouth MTY © D. Roberson ; next two (same bird, first year examples) can show a greatly reduced dark wedge.