Re: Blue-headed and Mountain Vireos
S.R. Freiberg (sammarcy@erols.com)
Sun, 05 Apr 1998 15:26:08 -0500
Hi Jim:
Thanks for the info on the two Eastern subspecies of Solitary Vireos.
For recording purposes, do you and Marshall want the code number 710 to stand for
Blue-headed Vireo instead of Solitary Vireo and do you want a separate code
number for Mountain Vireo?
Enjoy Birding!
Sam Freiberg
Chevy Chase, MD
sammarcy@erols.com
Jlstasz wrote:
> Hi Folks!
>
> As many of you know, the Solitary Vireo complex was split into Blue-headed
> Vireo [in the East], Plumbeous Vireo [in the West], and Casin's Vireo [in the
> northwest]. The National Geographic Field Guide and a recent article in
> Birding magazine cover these nicely.
>
> What many do not know is that there are two subspecies of Solitary Vireos
> described from the East...both are now call Blue-headed Vireo. The source most
> will have is Arthur Cleveland Bent's "Life Histories of North American
> Wagtails, Shrikes, Vireos, and their allies" . The Blue-headed Vireo (Vireo
> solitarius solitarius) is supposedly only a migrant through Maryland. The
> Mountain Vireo (Vireo solitarius alticola) is supposedly the breeding form.
> Compared to Blue-headed Vireo, Mountain Vireo is slightly larger, has a grayer
> back, and reportedly has a sightly different song. Mountain Vireo breeds in
> Appalachians [and Piedmont?] north to about Pennsylvania. Blue-headed Vireo
> breeds from Pennsylvania north.
>
> Because most birders have been unaware of the differences, few have kept field
> notes with the detail to help solve some questions.
>
> (1) Are the two forms really separate? Plumage? Song? Call note?
> (2) Do the two forms have different migration routes?
> (3) Is there a difference in timing of migration?
> (4) What are the real limits of the breeding ranges?
>
> I would ask that you take up the challenge this Spring and spend a little
> extra time looking at and listening to Blue-headed Vireos. Can you keep track
> of the birds you find and note them as:
>
> (1) Blue-headed Vireo [subspecies uncertain]
> (2) Blue-headed Vireo (Vireo solitarius solitarius) [the smaller green-backed
> migrant]
> (3) Mountain Vireo (Vireo solitarius alticola) [the larger grayer-backed
> breeder]
>
> In Maryland, the earliest spring arrival date is March 22. Peak migration is
> from about April 20 to about May 5. The earliest egg date is June 1, and the
> latest egg date is June 29.
>
> Good Birding!
>
> Jim Stasz
> North Beach MD
> jlstasz@aol.com