Piranga rubra
summer tanager

Summer tanagers breed throughout the eastern United States south of southern Pennsylvania and northern Illinois, in the southwestern United States and in northern Mexico. They winter from central Mexico through northern South America, as far south as Bolivia and Brazil (Robinson 1996).

In summer in the eastern portion of its range, summer tanagers primarily inhabit open woodlands of mixed oak and other hardwood trees. In the west, they live in riparian woodlands of cottonwoods and willows. They are also sometimes found in orchards, parks and roadside trees. In the winter, they continue to inhabit open woodlands, as well as tall secondary growth, gallery forest, forest edge, shaded plantations, and trees in parks and gardens along city streets. In Mexico, summer tanagers inhabit humid evergreen forest and tropical deciduous forest. Summer tanagers are typically found at low elevations, though they winter as high as 1800 m in Panama. (Robinson 1996; Isler and Isler 1987)

Summer tanagers are medium-sized birds, though rather large in comparison to other tanagers. They measure approximately 17 cm long and weigh an average of 30 g. Males are bright rose or orange-red throughout the year, and are distinguished from the scarlet tanager because their plumage is paler--not an intense scarlet--and because the summer tanager's wings and tail are red rather than black. Adult male summer tanagers have no crest. Females are olive above and orange-yellow below. They have conspicuous narrow yellow edging on their wing coverts. Some females develop complete male pigmentation as they age. Juvenile summer tanagers resemble adult females, but males often develop distinctive patches of red during the first winter.

There are two recognized subspecies of summer tanagers. The subspecies P. r. cooperi has paler plumage and is found in the western part of the range. The subspecies P. r. rubra has shorter wings, tails and legs and breeds primarily in the eastern part of the range. Robinson 1996; Isler and Isler1987; Terres,1980)

Summer tanagers breed once annually, and raise one brood per summer. They are serially monogamous, that is, they keep one mate throughout each breeding season, but not necessarily in successive seasons. Breeding pairs form soon after arriving on the breeding grounds in the spring, and split up after the young disperse late in the breeding season. Male summer tanagers arrive on the breeding grounds in full song, usually a few days before females arrive. Courtship begins with frequent, sudden, energetic chases of the female by the male. Males may also display before the female, carrying food items and hopping about. Little else is known about summer tanager courtship.

Summer tanagers breed once annually, and raise one brood per summer. They serially monogamous and sexually mature at one year of age. Breeding pairs form soon after arriving on the breeding grounds, and split up after the young disperse late in the breeding season.

Nest building begins 2 to 4 weeks after the birds arrive on the breeding grounds in spring. The nest is usually built out on a horizontal branch about 2.5 to 10.5 m from the ground. The female builds the nest alone, though she is often accompanied by the male while searching for a site and suitable nest-building materials. The nest is constructed primarily of dried herbaceous vegetation, and lined with fine grasses. There seems to be some regional variation in the quality of summer tanager nests; birds in the eastern range usually build flimsy and ragged nests, while the nests of summer tanagers in the western part of the range are sturdy and well-constructed. (Robinson 1996; Isler and Isler 1987; Terres 1980)

Egg-laying begins immediately after the nest is completed. The female lays 3 to 4 eggs that are smooth and somewhat glossy, pale blue or pale green, and spotted reddish brown. Incubation is carried out by the female only and lasts 12 to 13 days. During this time, the male spends a lot of time resting and caring for his feathers. In some pairs, however, the male feeds the incubating female, who may beg him for food. The chicks are fed by both parents after hatching, though males may do so indirectly by first giving the food to the female, who then gives it to the chicks. The young are fed primarily whole food, though some regurgitated food is also given. After 8 to 10 days, the young leave the nest, and by day 10, they are can make short, fluttery flights. The adults attend the young for 2 to 4 weeks after fledging. (Robinson 1996; Isler and Isler 1987; Terres 1980)

The female lays 3 to 4 eggs, which she incubates for 12 to 13 days. During this time, the male may feed the female. Both parents feed the altricial chicks during the nestling stage, which lasts 8 to 10 days. The female also broods the chicks for at least four days after hatching. Both parents feed the chicks for 2 to 4 weeks after they fledge.

During the nestling stage, both parents sanitize the nest by removing fecal sacs. (Robinson 1996; Isler and Isler 1987; Terres 1980).

The longest recorded lifespan of a summer tanager is 5 years. There is very little information on survivorship and life span of this species (Robinson 1996).

Summer tanagers are usually solitary birds, except during the breeding and migratory seasons. Pairs are seldom seen by humans, as they tend to conceal themselves in the tops of the tallest trees. The song of the male is quite recognizable, being rich and musical, not buzzy or harsh like the song of the scarlet tanager. The male sings vigorously all day during the breeding season, especially while trying to attract females and establish a territory. Some females sing a garbled version of the males’ song. Both sexes give a loud, clicking call, which is used in various situations.

The summer tanager is migratory. Migratory flocks can be as large as 30 individuals, though it is not known if these flocks fly together or simply gather when on the ground. Tanagers sometimes join mixed-species flocks, especially at forest edges and fruiting trees.

Tanagers generally migrate at night, as shown by the presence of many TV tower casualties. They also sleep primarily at night, though they sometimes take brief naps during the day. Their flight is swift and direct. The summer tanager often sits still on its perch, and then moves in sudden bursts. Breeding pairs preen frequently, and individuals occasionally sunbathe.

Male summer tanagers defend their nest site and a feeding territory during the breeding season. After arrival on the breeding grounds, rival males give vigorous flying chases in competition for territory. There is some physical contact between males at this time. Males also engage in a lot of counter-singing at the beginning of the breeding season. During the incubation period, males have been observed chasing females back to the nest. Should the male hear the song of an intruder male within his territory, he will respond by searching him out (Robinson, 1996; Isler and Isler, 1987; Terres, 1980).

There is no data available on the home range of scarlet tanagers. Territory sizes have not been well-studied, but one study found territory sizes of 90,000 to 110,000 square meters (Robinson 1996).

Summer tanagers communicate using vocalizations and physical displays. Male summer tanagers defend their nest site and territory by singing and chasing rival males, sometimes coming into physical contact during these chases. They also engage in counter-singing at the beginning of the breeding season. This is the practice of singing in response to neighboring males. Males attract mates by singing and chasing the females. Summer tanagers have a musical song unlike the buzzy songs of other tanagers. They also use several call notes to communicate (Robinson, 1996; Isler and Isler, 1987; Terres, 1980).

Summer tanagers are primarily insectivorous, eating a wide variety of flying and non-flying insects, such as beetles (order Coleoptera), dragonflies (suborder Anisoptera), grubs, cicadas (family Cicadidae), grasshoppers, ants (family Formicidae), caterpillars, weevils and spiders (order Araneae). They also eat fruits such as blackberries, whortleberries, mulberries, pokeweed, citrus and bananas, especially during the late breeding season, migration and on the winter range. However, the primary components of summer tanagers’ diets are bees (superfamily Apoidea) and wasps. They frequently attack wasp nests until the wasps abandon their nest, leaving the larvae for the tanager to devour. Summer tanagers occasionally capture food on the ground, but forage primarily in the tops of trees, where adult bees and wasps are caught in flight. Once prey has been caught, tanagers take the insect back to a perch and beat it against the perch until it dies. By wiping wasps on a branch before eating them, tanagers removes the stingers and other inedible body parts. (Robinson, 1996; Isler and Isler, 1987; Terres, 1980)

Predation of summer tanagers has not been directly observed. However, summer tanagers have been seen reacting aggressively to blue jays, Cooper’s hawks, raccoons, squirrels and black rat snakes, suggesting that these are potential predators. Summer tanagers do mob predators, diving at them and calling vigorously. (Robinson 1996)

Summer tanagers affect the populations of the insects they eat. They also spread seeds of the plants whose fruits they eat. They host at least three species of external parasites, including a louse (Philopterus subflavescens) and two mites (Trombicula irritans and Sternostoma pirangae).

Summer tanagers eat insect species that some people consider to be pests, such as bees and wasps.

There are no known adverse affects of summer tanagers on humans.

The North American breeding population of summer tanagers has remained relatively steady, and there are no pressing concerns for protection of this species. They are not protected under the U.S. Endangered Species Act, but are protected by the U.S. Migratory Bird Act. The most significant human impact on this species is probably destruction of breeding habitat. However collision with television towers during nocturnal migrations is also a significant source of mortality.

There are two recognized subspecies of summer tanager: P. r. cooperi in the west, and P. r. rubra in the east. (Robinson 1996)

Summer tanagers are also known as beebirds, calico warblers, and crimson tanagers.