Hi All, We are fortunate to have John Confer, one of the world's foremost experts on Blue-winged Warbler and Golden-winged Warbler, in our midst, so I'm hoping that he can provide a more insightful commentary on this topic than I can. But, I did want to point out that both the Blue-winged Warbler BNA account (which John co-authored) and the Golden-winged Warbler BNA account (which he authored and co-revised) make it clear that hybrids between the two species do not sing intermediate songs and are therefore not identifiable by song as a hybrid (let alone the type of hybrid):
>From the Blue-winged Warbler BNA Account: Songs of hybrids typical Blue-wing or Golden-wing; not intermediate or more variable in hybridizing populations, in contrast to plumage color. And from the Golden-winged Warbler BNA Account: Songs of hybrids match those of the parental species and are not intermediate in form (Ficken and Ficken 1967, Gill and Murray 1972b)....Census techniques that use bird calls face severe difficulty with Golden-winged and Blue-winged warblers. Hybrids will be identified as one or the other species. The pre-dawn singing bouts of type II song are very similar for both species, and difficult to distinguish. Going a step further, the song situation between Blue-winged Warbler and Golden-winged Warbler is very complicated, with Blue-winged Warblers capable of singing Golden-winged Warbler song and vice versa. Therefore, it is my understanding that no winged warbler can be safely identified to species (let alone hybrid type) with 100% confidence without visual confirmation. For those interested in listening to the vocal variability in this group, here are the 164 Vermivora recordings archived at the Macaulay Library: http://macaulaylibrary.org/search?taxon=vermivora&taxon_rank_id=62&taxon_id=12023487&tab=audio-list&order=taxa&page=1 (This includes four Bachman's Warbler recordings at the top, and 32 hybrid recordings on Page 2.) And for those interested in more reading, both Birds of North America accounts contain extensive "Sounds" sections that discuss interspecies discrimination and related topics in the two species. Good birding, Matt Medler Ithaca P.S. John, I hope that I got this all right! I'm sure we'd all enjoy hearing additional comments from you. ________________________________ From: Wesley M. Hochachka <w...@cornell.edu> To: CAYUGABIRDS-L <cayugabird...@list.cornell.edu> Sent: Saturday, May 17, 2014 8:52 PM Subject: [cayugabirds-l] likely Golden-winged/Brewster's Warbler on Hammond Hill this morning Hi everyone, Apologies for my late posting, but I only now had a chance to scan through a large number of recordings of singing warblers, and concluded that there was either a Golden-winged or Brewster’s Warbler on Hammond Hill this morning. The bird was heard by me, Scott Haber, and Brad Walker on the trail labelled “Yellow 6”. If you travel the trail across the road from the Hammond Hill Rd parking lot in the state forest, you will be on the “Yellow 1” trail. At a point just above the old blow-down area that has both Mourning and Canada Warblers (putting on good performances this morning!), the trail comes to a T-intersection, and if you turn left at the T (onto the “Yellow 6” trail) and travel between 50 and 100m you will come to a more open area before the conifer forest, which looks like an old apple orchard that has been overgrown for many years. We heard, but were not able to see, a bird that was singing persistently for at least 10 minutes, giving a 2-note song that sounds like an abridged version of one of the typical Golden-winged Warbler songs: a longer buzz, followed by multiple shorter notes at a slightly lower pitch for the typical song. The bird in question consistently sang only the first long buzz note and then a single shorter note. I found a couple of examples on xeno-canto that display this variant: http://www.xeno-canto.org/103587 http://www.xeno-canto.org/49544 However, after listening to every Golden-winged Warbler recording on xeno-canto, I think that anything that a pure Golden-winged Warbler can sing can also be sung by a Brewster’s Warbler (there were a few recordings of Brewster’s Warbler hybrids listed with the Golden-winged Warblers. So, I think that there’s at least 50% of a Golden-winged Warbler (possibly less if you go by mitochondrial DNA) up on Hammond Hill. If anyone is in the area, it might be useful to have a look and listen in the general area that I described. Wesley Hochachka -- Cayugabirds-L List Info: Welcome and Basics Rules and Information Subscribe, Configuration and Leave Archives: The Mail Archive Surfbirds BirdingOnThe.Net Please submit your observations to eBird! -- -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
