A startling sight in the canopy

By BILL CHAISSON
Of a Feather
In his iconic field guide, Roger Tory Peterson described the song of the scarlet tanager as “four or five, short, nasal phrases, robin-like in form but hoarse (like a Robin with a sore throat).” This less than complimentary description of its song contrasts strongly with the bird’s appearance. “Birding New England” avers that “a flaming red bird with black wings can only be one thing in the New England states.”

The cardinal is more completely red with black only around the bill, but it is a more saturated color that can not be compared to a flame. The Baltimore oriole is another bird that reminds the viewer of a feathered conflagration, and several of the wood warblers are similarly fiery, although aside from the redstart and Blackburnian warbler, most of them make do contrasting black with vibrant yellows. But when you go to www.allaboutbirds.org and type “scarlet” into the search box, only one species comes up; there is no other scarlet bird in North America.

In my September 29, 2018, column, I examined “the Neotropicals,” species that originated in the low latitudes of the New World and have radiated northward to become largely migratory species in North America, journeying back toward their point of origin after they are done breeding. All the species mentioned above fit this bill (with the exception of the non-migratory cardinal).

In the eastern United States we have only the scarlet (Piranga olivacea) and summer tanagers (P. rubra). The latter does not normally venture above the Mason-Dixon line, although one was spotted in Newmarket on May 29, according to the NHBirds forum. “The Birds of New Hampshire” (Allan R. Keith and Robert P. Fox; 2013) note that sightings in spring and early summer have been increasing since the 1990s. In contrast, the scarlet tanager breeds regularly north into southern Canada. The “Atlas of Breeding Birds in New Hampshire” describes it as “common in appropriate habitat throughout most of the state.”

Appropriate habitat consists of mature deciduous woodland, preferably including a healthy contingent of oaks with some pine and hickory mixed in. The Atlas writer suggests that hardwood regeneration in clear-cuts of former spruce-fir forests north of the White Mountains has allowed the tanager to become more common up there. These are not inhabitants of suburbia; they prefer to breed in large tracts of forest, although in the spring and fall migration they can be seen in more open places. They are forest dwellers on their wintering grounds as well, which extend from northern South America to the Bolivian lowlands.

This spring, I found a pair of them living along the Sunapee-Ragged-Kearsarge (SRK) trail in North Sutton. I was alerted to their presence by their characteristic call note, usually rendered as “chuck-birr” (although the Atlas author believes it sounds more like “keep-back”). When I heard it, I automatically looked up to the top of the canopy because that is where tanagers generally stay. I was rewarded with the sight of the male and, briefly, the female.

Unlike the male, the female is modestly colored. She is a yellowish olive-green above with dusky brownish-gray wings and tail. The underparts are light yellow, shading to olive-greenish to the sides. A pretty bird to be sure, much like the female orioles, but definitely adapted to stay hidden on the nest, as the male is adapted to serve as a beacon that marks their arboreal territory. In the fall, the males molt into a plumage similar to the female’s, but with darker wings and tail. The species apparently received its trivial name “olivacea” based on a winter specimen.

Wood warblers move through the canopy like manic, wind-up toys. Vireos, while more deliberate, are relatively active too. Tanagers, on the other hand, are downright lethargic. My 1917 “Birds of America” volume, always to be relied upon for elaborate subjectivity, puts it thusly: “To speak candidly, this tanager is usually a rather stupid and lifeless bird in its action. It moves about with an air of being dull-witted or dazed or, perhaps, bored. Also it has a characteristic trick of peering, with its head cocked first to one side and then to the other, as though it were in doubt about something.”

This last maneuver is perhaps related to their affection for caterpillars, particularly the leaf-rolling types. The slow, deliberate movements of the tanager are its way of methodically searching its habitat for food that may require careful extraction. They are particuarly destructive of the gypsy moth, which certainly excuses their plodding manner. It is also fond of click-beetles, leaf-eating beetles and crane flies.

The tanagers of North America are not actually related to those that breed in Latin America. The Thraupidae are one of the most diverse families in the bird world and constitute 12% of all Neotropical species. The genus Piranga or “northern tanagers” were long classified as part of this family. As late as 2000, David Sibley was still putting Piranga in the Thraupidae, and the Animal Diversity Web considered them a “genera incertae sedis” or of uncertain affiliation. As has so often been the case since the now-classic work of Charles Sibley (no relation to David) and Jon Ahlquist in the 1980s, modern molecular genetic studies have rearranged our ideas of relatedness. In 2009 the northern tanagers — there are nine species, with five reaching North America — were removed from the Thraupidae and placed in the family Cardinalidae.

Bill Chaisson, who has been a birdwatcher since age 11, is a former editor of the Eagle Times. He now works for the Town of Wilmot and lives in Sutton.