Scientific name: Piranga olivacea
Common name: Scarlet Tanager
(Information for this species page was collected in part by Mike Porter for
Biology 220W, Spring 2005 at Penn State New Kensington)
The scarlet tanager (Piranga olivacea) is a stunning, summer resident
of our campus nature trail. The distinctive black and red breeding plumage of
the male tanager is both breathtaking and unmistakable.
The scarlet tanager is between 6.5 and 7.5 inches long with a wing-span of
about one foot. It weighs just under one ounce. Non-breeding males, females, and
immature tanagers are dull green on their backs and yellow on their bellies. The
males can be distinguished from the females and immatures by their darker
colored wings and tails. When breeding season begins (May) the male tanagers'
body colorations turn bright red and their wings and tails become black.
Range and Migration Pattern
The scarlet tanager is a migratory species. It spends the winter months in the
tropical forests of Mexico and Central America. Its summer range extends broadly
across the United States (especially the eastern and mid-western U.S.) and up
into southern Canada. Breeding populations of scarlet tanagers have been
reported from every county in Pennsylvania but are most commonly found in the
mountains of the central and western parts of the state. It has been estimated
that 13% of all of the breeding pairs of scarlet tanagers are found in
Pennsylvania making our state extremely important in the breeding ecology of
this species! Tanagers are most often found in dry, mature woodlands and pine
forests but may occasionally be sighted in wooded parks and even in residential
areas if there are large trees present. Migrating tanagers do make the flight
from winter to summer ranges (or vice-versa) in one trip. They typically utilize
a wide variety of "stop-over" habitats along the way in which they feed and rest
before resuming their long journey.
Breeding and Reproduction
Breeding season for the scarlet tanager is from May to August. During this time
the brightly colored males
who arrive in the breeding range some days or weeks before the females sing and
vie with each other for territory within their forested habitats. Tanagers
require large, continuous forests for their breeding territories and are
negatively affected by the on-going, human-induced forest fragmentation which is
severe especially in tanager's breeding regions of the eastern and mid-western
United States. Tanagers make loosely constructed, cavity-shaped nests out of
twigs, rootlets, weed stems, and grasses. They then line these nests with pine
needles and fine grass. The nests are typically located in trees twenty to forty
feet above ground level although some nests have been observed over a broader
range of four to seventy-five feet above the ground. Eggs are typically laid
from mid-May to mid-June. These eggs are a pale blue-green with brown speckles
and are laid in clutches of four or five. The eggs are incubated for 13 to 14
days by the female. The young remain in the nest for 9 to 11 days after hatching
and are brooded by the female but fed by both parents. There is only one brood
per year for this species.
The scarlet tanager forages for food up in the tree canopy, in shrubs and
bushes, and also on the ground. Insects (including aphids, weevils, wood borers,
leaf beetles, cicadas, scale insects, dragonflies, ants, termites, caterpillars
(including gypsy moth caterpillars), parasitic wasps, and bees) make up the bulk
of their diet along with a variety of fruit (including mulberries, June-berries,
huckleberries, and other wild fruits). Females tend to forage high up in the
tree canopy and also tend to eat more flying insects.
Human Impacts on Habitat
As previously mentioned, forest fragmentation in the tanagers' breeding ranges
seriously impacts both mating and fledgling successes. Forest fragmentation also
increases the incidence of nest parasitism by brown-headed cowbirds and nest
predation by blue jays and crows. Also, loss of tropical forest habitats in
Mexico (especially in the Yucatan Peninsula) and Central America has resulted in
declining numbers of this and many other neotropical migrant birds. Pesticides
and lawn chemicals also have been to shown to have deleterious effects upon
tanagers (and other song birds as well).
Behavior - "Anting"
Tanagers, like many other bird, mammal, and reptilian species, display a
behavior called "anting." Anting involves an animal adding ants either singly or
in large groups to it skin. Tanagers have been observed spreading out their
wings and actually laying down on top of an anthill in order to maximize their
exposure to the ants. The ants only transiently stay on the animal and,
apparently, leave behind a residue of their secreted chemicals. Historically it
has been assumed that anting helps the animal either rid itself of skin
parasites or that it conveys some level of protection against future parasitic
infections. Some researchers, however, have noted that tanagers and other anting
birds tend to be going through a feather molt when they display this behavior.
Possibly, they hypothesize, the anting offers some relief to the bird from the
skin irritation and discomfort which comes with the molting process.
The song of the scarlet tanager is similar to that of the American robin
although it is a bit more hoarse and breathy (one expert described it like a
robin singing with a sore throat). Especially during the early summer breeding
season the "querit-queer-query-querit-queer" can be heard throughout the
forested habitat of our nature trail and in many other sites throughout our
western Pennsylvania area.