the scarlet tanager (piranga olivacea) is a medium-sized american songbird .
until recently placed in the tanager family (thraupidae), it and other members of its genus are now classified as belonging the cardinal family (cardinalidae) .
the species' plumage and vocalizations are similar to other members of the cardinal family , although the piranga species lacks the thick conical bill (well suited to seed and insect eating) that many "cardinals" possess .
the scarlet tanager , a mid-sized passerine , is marginally the smallest of the four species of piranga that breed north of the mexican border .
it can weigh from 23.5 to 38 g (0.83 to 1.34 oz), with an average of 25 g (0.88 oz) during breeding and an average of 35 g (1.2 oz) at the beginning of migration .
scarlet tanagers can range in length from 16 to 19 cm (6.3 to 7.5 in) in length and from 25 to 30 cm (9.8 to 11.8 in) in wingspan .
adults of both sexes have pale horn-colored , fairly stout and smooth-textured bills .
adult males are crimson-red with black wings and tail .
the male's coloration is intense and deeply red , similar but deeper in shade than the males of two occasionally co-existing relatives , the northern cardinal and the summer tanager , both which lack black wings .
females are yellowish on the underparts and olive on top , with yellow-olive-toned wings and tail .
the adult male's winter plumage is similar to the female's , but the wings and tail remain darker .
young males briefly show a more complex variegated plumage intermediate between adult males and females .
the somewhat confusing specific epithet olivacea ("the olive-colored one") was based on a female or immature specimen rather than erythromelas ("the red-and-black one"), which authors attempted to ascribe to the species throughout the 19th century (older scientific names always takes precedence , however) .
female , immature and non-breeding males may be distinguished from the same ages and sexes in summer tanagers , which are more brownish overall , and western tanagers , which always have bold white bars and more yellowish undersides than scarlet tanagers .
the song of the scarlet tanager sounds somewhat like a hoarser version of the american robin's and is only slightly dissimilar from the songs of the summer and western tanagers .
the call of the scarlet tanager is an immediately distinctive chip-burr or chip-churr , which is very different from the pit-i-tuck of the summer tanager and the softer , rolled pri-tic or prit-i-tic of western tanager .
their breeding habitat is large stretches of deciduous forest , especially with oaks , across eastern north america .
they can occur , with varying degrees of success , in young successional woodlands and occasionally in extensive plantings of shade trees in suburban areas , parks , and cemeteries .
for a viable breeding population , at least 10 to 12 hectares of forest are required .
in winter , scarlet tanagers occur in the montane forest of the andean foothills .
scarlet tanagers migrate to northwestern south america , passing through central america around april , and again around october .
they begin arriving in the breeding grounds in numbers by about may and already start to move south again in mid-summer; by early october they are all on their way south .
the bird is an extremely rare vagrant to western europe .
scarlet tanagers are often out of sight , foraging high in trees , sometimes flying out to catch insects in flight and then returning to the same general perch , in a hunting style known as "sallying" .
sometimes , however , they will also capture their prey on the forest floor .
they eat mainly insects , and will opportunistically consume fruit when plentiful .
any flying variety of insect will readily be taken when common , such as bees , wasps , hornets , ants , and sawflies; moths and butterflies; beetles; flies; cicadas , leafhoppers , spittlebugs , treehoppers , plant lice , and scale insects; termites; grasshoppers and locusts; dragonflies; and dobsonflies .
scarlet tanagers also takes snails , earthworms and spiders .
while summer tanagers are famous for this feeding method , when capturing bees , wasps and hornets , scarlet tanagers also rake the prey against a branch in order to remove their stingers before consumption .
plant components of their diet consists of a wide variety of fruits that eaten mainly when insects are at population lows including: blackberries (rubus allegheniensis), raspberries (r .
ideaus), huckleberries (gaylussacia sp .
), juneberries and serviceberries (amelanchier spp .
), mulberries (morus rubra), strawberries (fragaria virginiana), and chokeberries (aronia melanocarpa) .
male scarlet tanagers reach their breeding ground from mid-may to early june .
females generally arrive several days to a week later .
nest building and egg laying both occur usually in less than two weeks after the adults arrivals .
the clutch is usually four eggs , occasionally from three to five and exceptionally from one to six eggs may be laid .
the eggs are a light blue color , often with a slight greenish or whitish tinge .
incubation lasts for 11 to 14 days .
hatching and fledging are both reached at different points in summer depending on how far north the tanagers are breeding , from june-early july in the southern parts of its breeding range to as late as august or even early september in the northernmost part of its range .
the average weight at hatching is 3.97 g (0.140 oz), with the nestlings increasing their weight to 2022 g (0.710.78 oz) by 10 days , or 70% of the parent's weight .
the young leave the nest by 912 days of age and fly capably by the time they are a couple weeks old .
if the nesting attempt is disturbed , apparently scarlet tanagers are unable to attempt a second brood as several other passerines can .
in a study of 16 nests in michigan , 50% of nests were successful in producing one or more fledglings .
in western new york , fledgling success increased from 22% in scattered patches of woods to as much as 64% in extensive , undisturbed hardwood forest .
exposure and starvation can occasionally kill scarlet tanagers , especially when exceptionally cold or wet weather hits eastern north america .
they often die from collisions with man-made objects including tv and radio towers , buildings and cars .
beyond failure due to brown-headed cowbirds (molothrus ater) (see below), predation is the primary direct cause of nesting failures .
in one study , 69-78% of nests were predated .
recorded nest predators are primarily avian like blue jays (cyanocitta cristata), common grackles (quiscalus quiscula) and american crows (corvus brachyrhynchos), although others like squirrels , chipmunks , raccoons (procyon lotor) and snakes probably take a heavy toll as well as an occasional unlucky fledgling as do cats (felis catus) .
raptorial birds hunt and kill many scarlet tanagers from fledgling throughout their adult lives , including all three north american accipiter species , merlins (falco columbarius), eastern screech owls (megascops asio), barred owls (strix varia), long-eared owls (asio otus) and short-eared owls (asio flammeus) .
these birds do best in the forest interior , where they are less exposed to predators and brood parasitism by the brown-headed cowbird .
the cowbird lays its eggs in most any other passerines nest and the young often outcompete the young of the host bird and may cause failure and starvation .
some birds have evolved strategies to deal with cowbird parasitism , but the scarlet tanager , being a bird that evolved to breed in forest interior and not previously exposed to this , are helpless victims to brood parasitism .
where forest fragmentation occurs , which is quite widespread , the scarlet tanager suffers high rates of predation and brood parasitism in small forest plots and are often absent completely from plots less than a minimum size .
their nests are typically built on horizontal tree branches .
specifically their numbers are declining in some areas due to habitat fragmentation , but on a global scale tanagers are a plentiful species .
thus , the iucn classifies the scarlet tanager as being of least concern .
