Pheucticus ludovicianus
rose-breasted grosbeak

Rose-breasted grosbeaks breed in northern North America, from British Columbia in the west to the Canadian maritime provinces in the east and as far south as New Jersey, the Appalachian Mountains through South Carolina, west to eastern Kansas, Nebraska, and the Dakotas. In winter they are found in the greater Antilles, coastal Mexico, and throughout Central America and northern South America to eastern Peru and Guyana. They are sometimes seen wintering in the lesser Antilles and Revillagigedo Islands as well. They are very occasionally seen in Europe. (Wyatt and Francis, 2002)

In their breeding range, rose-breasted grosbeaks are found in a wide variety of wooded habitats, including swamp or mesic forests, riparian corridors, and forest edges along marshes, roads, and pastures. They prefer mixed or deciduous woodlands with an open structure, such as second-growth habitats. They seem to avoid dry woodlands and grasslands. They are found in similar kinds of habitats along migratory routes and in their winter range. They are found at elevations up to 3800 m in Colombia. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks are sexually dimorphic in plumage pattern. Males have vivid black and white feathers with a rose-colored throat, females have brown and white streaked plumage, with a distinct, buffy eyestripe. Rose-breasted grosbeaks are 18 to 21.5 cm long and from 39 to 49 grams. Males have a black head, white bill, are black and white dorsally and have a white belly and breast, topped with their rosy throat. Females are brown with white markings above and buffy with brown streaks on the belly, breast, and throat. Immature and non-breeding males take on some female plumage characteristics, such as the buffy white superciliary stripe and some brown and streaked plumage. There are no subspecies. (Wyatt and Francis, 2002)

Rose-breasted grosbeak females are almost identical to females of the closely related black-headed grosbeaks (Pheucticus melanocephalus), although they tend to have more streaking on their breasts. Although the males of these two species differ in pattern, hybridization does occur where their ranges overlap in the central U.S. and southern Canada. The two species are ecologically similar and have similar songs. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks are monogamous, but no research has been done on extra-pair copulations. Pair bonds are formed in spring on the breeding grounds, when females approach territorial, singing males. Males may first reach aggressively towards females. Males use several kinds of courtship displays with females: the rapid warble flight and wing-fluff, both of which are accompanied by a warbling song. Warble flight involves the male flying slowly with his tail spread and with small movements of the wings, the wing-fluff involves the male holding his wings out to the side with his tail spread and moving his head and body from side to side as he hops on a branch. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks begin building nests in May and lay from 1 to 5 (usually 4) pale, bluish-green eggs speckled with darker colors. Nests are constructed in trees, shrubs, or vines from 0.8 to 16.8 m high. Nest are constructed of loosely woven grass and twigs formed into cup-shapes. Finer materials line the nest, such as shredded bark, pine needles, and fine grasses. Generally 1 brood is laid each year, although second broods are sometimes attempted. Females lay eggs about once per day until the clutch size is reached and begin incubating at the next to last egg laid. Eggs hatch asynchronously from 11 to 14 days after the beginning of incubation and young fledge after 9 to 12 days. The young are dependent on their parents for another 3 weeks after fledging and remain with the parents throughout the summer until migration. Young are able to breed in their first year after hatching. (Wyatt and Francis, 2002)

Both females and males incubate the eggs and brood the young. Young are altricial at hatching, with light down and weighing about 4.5 g. Males and females both provide food for the young throughout their nestling period. They provide up to 75% crushed insects to the young. (Wyatt and Francis, 2002)

The oldest reported wild bird was banded at almost 13 years old. Captive birds have lived up to 24 years. Estimates of annual survival are 48% in young birds and 61% in adults. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks are migratory, with no overlap in breeding and wintering ranges. They avoid migrating across Great Plains habitats. They leave their wintering grounds from mid-March to mid-April, arriving on the breeding grounds as early as late March and as late as early May. In fall, southward migrations begin in early September and continue into early November. They migrate at night, usually in small flocks or alone. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks hop on the ground and have an undulating flight pattern. When startled they often freeze and they will flick their wings, spread their tails, raise their head feathers, and give chase in aggressive encounters. Males exclude other males from breeding territories and females exclude other females. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks often return to the same breeding area year after year. There is no published information on home range size, but there is some evidence that males disperse farther from natal sites than do females. Population densities reported are from 0.3 to 0.6 pairs per 10 hectares in the breeding season. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks are known for their lovely, melodic song. Males sing to advertise breeding territories, up to 689 songs in a day. Females may also sing when they are building nests. Other calls used include a sharp "chink" contact call and various squawks, chuks, and hurrrs used in different contexts. Young first make sounds at 6 days after hatching and young males produce their first songs at about 30 days old. Songs seems to be learned. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks eat seeds, fruit, and insects, with proportions varying seasonally. During the breeding season they eat approximately 52% insects and 48% seeds and fruit. They may also eat the ovaries of flowers. During migration they rely heavily on fruits. There is less known about winter range diet, except that it includes fruits and oil-rich seeds. Rose-breasted grosbeaks forage throughout forest canopy levels and occasionally on the ground. They glean insects from leaves or can hover or hawk to capture insects. They often eat the fruiting body off of seeds or extract only the germ of seeds to eat. Insects eaten include beetles, including Colorado potato beetles (Leptinotarsa decimlineata), bees and ants, bugs, and butterfly larvae. They prey heavily on wild fruits such as elderberry (Sambucus canadensis), red-berried elder (Sambucus pubens), blackberry and raspberry (Rubus species), mulberry (Morus rubra), and juneberry (Amelanchier canadensis), and weed seeds, such as smartweed (Polygonum), pigweed (Amaranthus), foxtail (Setaria), milkweed (Asclepias), and sunflowers (Helianthus). They may also eat domestic crops, such as peas (Pisum sativum), corn (Zea mays), oats (Avena sativa), and wheat (Triticum vulgare). (Wyatt and Francis, 2002)

Most predation is on eggs and nestlings. Rose-breasted grosbeak pairs will attack or mob perceived threats near their nests. Reported nest predators are blue jays (Cyanocitta cristata), common grackles (Quiscalus quiscula), grey squirrels (Sciurus carolinensis), and red squirrels (Tamiasciurus hudsonicus). Adults may be preyed on by Cooper's hawks (Accipiter cooperii) and sharp-shinned hawks (Accipiter striatus). (Wyatt and Francis, 2002)

Rose-breasted grosbeak nests are parasitized by brown-headed cowbirds (Molothrus ater). However, aggressive nest defense by parents may make parasitism unlikely and the survival of grosbeak nestlings seems unaffected by parasitism. Other parasites are lice (Brueelia pallidula and Menacanthus eurysternus) and parasitic flies (Ornithoctona strigilecula and Ornithomyia anchineuria). Rose-breasted grosbeaks may help to disperse some seeds and control local insect populations. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks are appreciated for their lovely song and the bright colors of the males. They are frequent visitors at bird-feeders.

Rose-breasted grosbeaks occasionally take domestic crops, such as peas, corn, oats, and wheat. (Wyatt and Francis, 2002)

Rose-breasted grosbeak populations seem to be stable, although there have been marginal declines in some areas. Individuals may die from collisions with buildings and towers during migration and forest succession towards mature forests may reduce available habitat for this species. The IUCN lists them as least concern because of their large population sizes and large range. (Wyatt and Francis, 2002)

Rose-breasted grosbeaks can hybridize with their close relatives, black-headed grosbeaks (Pheucticus melanocephalus), especially in Nebraska and the Dakotas. There seems to be assortative mating in areas of hybridization, with hybrids preferring to mate with other hybrids. Hybrid females lay smaller clutch sizes, on average. (Wyatt and Francis, 2002)