Many birders have a “spark bird,” a species that captured their attention and inspired lifelong interest in birds. For me, it was the Scarlet Tanager (Piranga olivacea). As a young girl I was given a copy of The Bird Guide: Land Birds East of the Rockies by an elderly neighbor, a vintage book even back then. In studying the illustrations, I could not believe that a bird as bright and stunning as the Scarlet Tanager could be found in Michigan; if so, it surely could not be as brilliant as the book portrayed. It was some years before I finally saw a male Scarlet Tanager, as they tend to be canopy dwellers. I have handled and seen countless others since then. Each time, like the first, I still marvel at their brilliance.
There are over 240 species of tanagers in the New World, and frankly they include some of the world’s most beautiful birds. They are really a tropical family, with only four species having evolved to migrate to North America to breed (a fifth is a rare breeder in the deep southwest). All of them retreat to the tropics to spend the winter.
The Scarlet Tanager breeds in large, mature, deciduous forest tracts over much of the eastern U.S. and southern Canada, save for the deep south, and spends the winter in northwestern South America, where they are most common in Ecuador, Bolivia, and the Peruvian Andes (range map here). During the nesting season, Scarlet Tanagers prefer to utilize the interior of large tracts of forest. Their sensitivity to fragmented habitats categorizes them as an “area sensitive” species. In small or fragmented woodlots, they suffer from predators and parasitism by cowbirds (which lay their eggs in the nests of other bird species, usually at the expense of their hosts). If a forest is too small (<10 ha), the tanagers will not attempt to nest at all.
After their breeding season, the tanagers molt into their more somber winter plumage. The males go from scarlet to bright olive with black wings. Females are a duller olive with dusky wings — the same color they are year round. This change from eye-catching to cryptic coloration is not unusual. Flashy colors are good ways to advertise for mates and let other birds know a territory is occupied, but are a little too conspicuous to predators the rest of the year. For North American migrant birds that share their wintering areas with many year-round resident birds in the tropics, it’s probably also a good strategy to be a little more modest.
Few species of North American migrant birds make it as far south in winter as the Scarlet Tanager. Their habits during winter are not well known, as they tend to be inconspicuous and spend most of their time in the canopy. While in the breeding season, Scarlet Tanagers eat insects almost exclusively, they also eat fruit in the winter. They have been recorded on shade coffee farms in Central America (Panama and Nicaragua) during migration, as well as in winter. As canopy dwellers, they utilize the shade trees and do not find sun coffee appropriate habitat.
Two of the other North American breeding tanagers, Western Tanager (P. ludoviciana) and Summer Tanager (P. rubra) are also found on shade coffee farms.
Perhaps few North American breeding birds remind us so strongly that they are not really “our” birds, but tropical species on loan for a few short months in the summer. When we contemplate that fact, it reminds us that habitat on the wintering grounds — such as shade coffee farms — are truly critical for their survival. Support shade-grown coffee, so that future generations can open a field guide, become inspired by a vivid tanager, and discover that they really do exist.
Female-plumaged tanager photo by Jamie Chavez under a Creative Commons license.