Blackburnian Warbler

Few birding experiences can compete with one’s first view of the blazing orange throat of a male Blackburnian Warbler. The prize is all the greater when you consider that Blackburnians spend most of their time high in hemlocks and other conifers and are thus often difficult to see. Their song, in contrast, is far less flashy, consisting of a few introductory notes followed by a short trill, all at an extremely high pitch. So in addition to being hard to see high in the trees, this species becomes hard to hear as we age and lose our high frequency hearing.

These treetop habits have made the Blackburnian Warbler a difficult species to study. Its nests are regularly built at 40 feet or above, making it the highest nesting warbler in eastern coniferous forests, and some have been twice that high. It also concentrates its singing and foraging in the highest portions of the same trees, with foraging mainly at the tips of branches.

Although Blackburnian Warblers are strongly associated with spruce-fir forest in the northern part of their range, including higher elevations in New Hampshire, to the south their preference shifts to hemlock. Hemlock forests in New England are now threated by an introduced insect, the hemlock wooly adelgid, and where this pest is well established warbler populations have declined. The insect is limited by cold winter temperatures, so as the climate warms it is likely to continue spreading north and impacting larger areas of forest. Forest loss is also a potential threat in the montane forests of northern South America where Blackbunrian Warblers spend the winter. Despite these threats, Blackburnian Warbler populations over most of its range are relatively stable, with the strongest decreases in the Appalachians where a different adelgid has affected fir trees.