During my medicine residency, in Morgantown, West Virginia, I would often go hiking and birding at a hemlock preserve, east of town. It was during one of those excursions that I first encountered black-throated blue warblers and, since leaving that region of the country, I have not seen them again.
Indeed, black-throated blue warblers breed in dense forests along the Appalachian Chain, from north Georgia to New England; they also summer in northernmost Minnesota and Wisconsin, on the Upper Peninsula of Michigan and across southeastern Canada. Adult males are unmistakeable with their striking slate-blue, black and white plumage; the dull olive-gray females, on the other hand, are nondescript in appearance and were once thought to represent another species. Since these warblers favor deep woods with heavy undergrowth, logging by early settlers threatened their existence but conservation measures and the reforestation of old farmlands has since stabilized their population.
Best found along forest trails, black-throated blue warblers are rather tame and tend to remain in the thick undergrowth, feeding on insects and berries. An open cup of bark, moss and spider web strands is placed in a shrub and 3-4 eggs are generally produced. Come September, these small, reclusive songbirds head for the Greater Antilles where they spend the northern winter in dense, tropical forest.
