Coming from a leafy shrub is the pure song of a Blue-winged Warbler, just as it sounds on your smart phone app. Searching for the songster, you find the singing bird but it definitely not the coloration of the Blue-winged in your field guide. Yikes! What to do?
The so-called “winged warblers” are a complex of Blue-winged and Golden-winged Warblers and their many hybrids. They are most commonly found in shrubby, abandoned farm fields. Two of the hybrids are known by the names Brewster’s Warbler and Lawrence’s Warbler. Population structures appear to be rapidly changing here in Vermont and elsewhere, and we are trying to keep track of what is going on.
As more and more observers in Vermont are hearing and seeing these birds, we should become more careful about how we report them. Attentive observers are documenting that there is no fidelity between the songs we hear and what species or hybrid might be doing the singing. You cannot trust what species or hybrid is singing by ear alone. Moreover, careful visual observations often report more birds with hybrid characteristics than birds with pure species plumage. All these different birds have been described as a “Winged-warbler soup … a real, bird-gene potpourri”.
So it becomes necessary, where possible, to carefully document the plumage of the singing bird. Not just the gross appearance, but in detail throughout – a from bill to tail, back to belly. Well, that sounds straight-forward enough, but these are warblers. And warblers don’t always sit waiting for their protrait. More often than not, you won’t be able to get the good looks you want or need.
Vermont eBird, therefore, has created these guidelines for submitting Winged-warbler observations. Each of the categories listed is already in use in eBird. Since the birds are complex, the guidelines are more complex than for most birds we report. Look very carefully at these categories, as some are quite similar to each other.
(a) Heard only, regardless of song —- submit as Blue-winged/Golden-winged Warbler.
(b) Birds seen only, plumage incompletely seen —- submit as Blue-winged/Golden-winged Warbler.
(c) Plumage well seen, clearly typical Golden-winged regardless of song, and carefully described —- submit as Golden-winged Warbler.
(d) Plumage well seen, clearly typical Blue-winged regardless of song, and carefully described —- submit as Blue-winged Warbler.
(e) Most birds showing traits of both Blue-winged and Golden-winged Warbler, regardless of song —- submit as Blue-winged x Golden-winged Warbler (hybrid).
(f) Plumage well seen, carefully described, and bearing signature plumage of Brewster’s Warbler —- submit as Brewster’s Warbler (hybrid).
(g) Plumage well see, carefully described, and bearing signature plumage of Lawrence’s Warbler —- submit as Lawrence’s Warbler (hybrid).
Check the “Show Rarities” box on the submission page if you want these categories to appear in the list of species to select from as you create your checklist. Or, you can use “Add Species” to go directly to the category(s) you want.
Thanks for your help in finding and documenting these beautiful, but complex, birds!