Rose-Breasted Grosbeak

The rose-breasted grosbeak is easy to identify because of its colors. It has a rosy breast, and the white bars on its wings are easily seen when it flies. Its big, conical beak is perfect for breaking the hard coverings of seeds, it has a beautiful song, and it has a contact call that sounds like “chink.” These birds prefer second-growth forests, which are the forests that return after the old-growth forests are cut down. The bird’s population is declining in some areas, and one reason may be that these second-growth forests are aging.

Scientific Name

The rose-breasted grosbeak’s scientific name is Pheucticus ludovicianus. Pheucticus comes from the ancient Greek for “shy” or “to flee,” and ludovicianus is New Latin for something from Louisiana. The bird was first described by a specimen that was collected by Mathurin Jacques Brisson in Louisiana. There are no subspecies of the rose-breasted grosbeak.

Evolution and Origins

The rose-breasted grosbeak belongs to the Pheucticus genus of grosbeaks and it is closely related to the cardinal, also a member of the Cardinalidae family of birds. Scientists have made two unusual discoveries in the recent evolutionary history of the rose-breasted grosbeak.

A bilateral gynandromorph rose-breasted grosbeak — meaning it is half male and half female — was found and banded in 2020 at Powdermill Nature Reserve in Westmoreland County, Pennsylvania. The bird displayed the typical appearance of a male in its red wing pits, red breast spot, and black wing feathers on its right side, while on its left side it had female colorations of yellow wing pits and brown, speckled wing feathers. Gynandromorph birds are rare and scientists are not sure why they form, but some theories involve a developmental error occurring when an egg forms, chromosome loss, and “unreduced” sperm in fertilization.

The rose-breasted grosbeak is part of a new hybrid bird that was first discovered and documented in 2020 in western Pennsylvania. It is a first-generation naturally occurring bird that is a cross between a rose-breasted grosbeak and a scarlet tanager (Piranga olivacea). DNA analysis confirmed that the bird, which was given the nickname “tanabeak,” had a rose-breasted grosbeak as its mother and a scarlet tanager as its father. Although these species both belong to the Cardinalidae family, shared an ancestor more than 10 million years ago, and are found in the same habitats throughout eastern North America, they have not historically been known to crossbreed. The male rose-breasted grosbeak hybrid had notable differences in plumage such as a throat colored pink instead of black and in morphology, including a longer, shallower, and darker bill.

Appearance

When it comes to coloration, the sexual dimorphism of the rose-breasted grosbeak is dramatic. A male who is ready to breed has a distinctive rose-colored breast patch, black wings, and a black back, head, and tail. His rump and belly are white, and his wings have white patches and rosy linings. Males who are not in their breeding plumage are also white below but have white cheeks and a white streak over the top of the head called the supercilium. The feathers on his back and his wings are fringed in brown or white, and the primary flight feathers on his wings are also white. Another name for the bird is “cut-throat,” because the male looks like his throat has been cut, and he has bled over his breast.

Female rose-breasted grosbeaks are dark brownish-gray on top, have a white supercilium and buff-colored stripe on the tops of their head, and have underparts streaked with black. They have two white patches on the upper wings, and the linings of the wings are yellow. Both males and females have robust, horn-colored bills and black eyes and feet. Juvenile males look like females.

This grosbeak species is between 7 and 9 inches long, has a wingspan of between 11 and 13 inches, and weighs between 1.2 and 2.3 ounces on average. Females may be just slightly smaller than males.

Behavior

Rose-breasted grosbeaks are strong flyers and can be identified by their dipping flight pattern as well as their colors, but on the ground, they hop. They are somewhat pugnacious and will chase away other birds, including birds as large as hawks or grackles. Most rose-breasted grosbeaks are not fooled when cowbirds lay their eggs in their nest and will kick the foreign egg out. Males are sometimes aggressive toward females until they realize it is of the same species and in mating season. These birds move among the trees and shrubs or searches on the ground to find food. They also grabs insects on the wing or hovers to catch them. They are also migratory birds.

The birds’ breeding range resides from northern Canada, as far west as British Columbia, and as far south as northern Georgia. They can leave for their wintering grounds as early as late summer, which include Central America, Cuba, Hispaniola, and the northern reaches of Venezuela and Colombia. Stragglers may not return to the breeding grounds till the middle of May. Birds tend to come back to the same breeding grounds every year. Rarely, a rose-breasted grosbeak is seen in Europe.

Though rose-breasted grosbeaks are territorial when they’re nesting, they sometimes gather in groups to forage in their wintering grounds.

Juvenile males begin to sing when they’re about a month old. The contact call reminds some people of the call of a woodpecker. Other calls include chucks, squawks, and burrs.

Habitat

The rose-breasted grosbeak breeds in North America and winters in Central America, South America, and the Caribbean. It can be found in forests, by rivers, in marshes and swamps along the edge of the woods, and especially in second-growth forests. The habitats of its breeding and wintering ranges are similar.

The nest of the rose-breasted grosbeak is built in trees, sturdy vines such as Virginia creeper, or shrubs. It is cup-shaped and made of grass and twigs and lined with finer grass, pine needles, hair, or shredded bark. They are usually from 2.6 to 55 feet from the ground, and sometimes so loosely constructed that the eggs can be seen through the bottom.

Diet

The bird eats a wide variety of insects and vegetation. When they are raising chicks, most of their diet will be insects, such as beetles, bees, bugs, ants, and caterpillars. They also take snails and spiders.

When they are migrating and in their winter range they eat fruit. The birds sometimes eat the fruit from around the seeds or use their strong beaks to take off the husks of seeds and only eat the germ. They will also eat flowers and buds from trees. In the winter range, they seek out seeds that are rich in oils. They eat mast and a lot of soft fruits including blackberries and raspberries, mulberries, and elderberries as well as the seeds of pigweed, milkweed, and sunflowers. They raid farms for peas, corn, and grains.

Foods that should not be given to rose-breasted grosbeaks include chocolate, which is toxic. Bread is useless nutritionally, and moldy bread can make them sick. Table scraps may also be harmful.

Predators and Threats

Predators that eat the birds, their chicks, or their eggs include squirrels, raccoons, grackles, blue jays, owls, and hawks. Other threats include colliding with cars and crashing into windows, being shot, or being caught by dogs or cats. Birds also die of diseases and bad weather, though reports on these causes of grosbeak mortality are scant.

Reproduction, Babies, and Lifespan

The breeding season is in spring when the birds come back from their winter range. Males stake out their territory and start to sing, which attracts the females. He may try to chase her away at first, then he performs a courtship display that includes fluffing up his feathers and a lovely, warbling song. If she accepts, they will pick out a place to build their nest.

After the nest is constructed, the female lays one to five eggs. They are blue-green and freckled with brown. Both parents sit on the eggs. They hatch all at once in about 10 days, and the chicks molt when they are only 9 to 12 days old. They will be taken care of by both parents for another three weeks. The chicks will mostly be fed mashed-up insects and will stay with their parents until it is time to fly south for the winter. The chicks will be able to reproduce themselves when they are about a year old.

Rose-breasted grosbeaks are long-lived birds, and in the wild they can live to be 13. The oldest rose-breasted grosbeak in captivity lived for at least 24 years.

Population and Conservation

The population of the rose-breasted grosbeak is about 4.1 million, and the population appears to be stable with some decline here and there. The IUCN Red List classifies this bird’s conservation status as Least Concern.