Rose-breasted grosbeaks are seed-eating birds that breed in cool-temperate North America and migrate to spend winter in tropical America. These birds have large dusky horn-colored beaks, and their feet and eyes are dark. Adult males in breeding plumage have a black head, wings, back, and tail, and a bright rose-red patch on their breast; the wings have two white patches and rose-red linings. Their underside and rump are white. Males in nonbreeding plumage have largely white underparts and cheeks. The upperside feathers have brown fringes, and most wing feathers white ones, giving a scaly appearance. The bases of the primary remiges are also white. The coloration renders the adult male rose-breasted grosbeak (even while wintering) unmistakable if seen well. Adult females have dark grey-brown upperparts, a buff stripe along the top of their head, and black-streaked white underparts, which except in the center of the belly have a buff tinge. The wing linings are yellowish, and on the upper wing are two white patches like in the summer male. Immature birds are similar, but with pink wing-linings and less prominent streaks and usually a pinkish-buff hue on the throat and breast.
Rose-breasted grosbeaks breed across most of Canada and the northeastern United States. The northern birds migrate south through the United States east of the Rocky Mountains, to winter from central-southern Mexico through Central America and the Caribbean to Peru and Venezuela. Rose-breasted grosbeaks inhabit open deciduous forests, mixed forests, and forest edges next to streams, ponds, marshes, parks, gardens, and plantations.
Rose-breasted grosbeaks are social birds and often roam the lands in small groups, and sometimes in larger flocks of a dozen or more. During the breeding season, they become fairly territorial. These birds are active during the day spending their time foraging in shrubs, trees or catching insects in flight. They usually keep to the treetops and only rarely can be seen on the ground. In the winter quarters, they can be attracted to parks, gardens, and possibly even to bird feeders. In general, Rose-breasted grosbeaks migrate south in late September or in October and return in late April or early May. These birds communicate with a sharp pink or pick, somewhat reminiscent of a woodpecker call. Their song is a subdued mellow warbling, resembling a more refined, sweeter version of the American robin's. Males start singing early, occasionally even when still in winter quarters.
Rose-breasted grosbeaks are serially monogamous and form pair-bonds that last during the breeding season. Males tend to arrive a few days to a week before the females and pair formation apparently occurs on the breeding grounds. The breeding season usually takes place from mid-May through July. Both the male and the female apparently participate in selecting and building the nest, which is on a tree branch, over vines or any elevated woody vegetation. Nests are made from leaves, twigs, rootlets or hair. Females lay clutches from 1 to 5 pale blue to green eggs with purplish to brownish red spotting. Incubation can last from 11 to 14 days done by both parents. Nestlings are altricial; they are hatched helpless, with closed eyes and weigh 5 g (0.18 oz). They usually fledge at 9-13 days of age and are independent of their parents after approximately 3 weeks. Young Rose-breasted grosbeaks become reproductively mature when they are 1 year old.
Rose-breasted grosbeaks are not threatened at present. However, these birds suffer from degradation of their habitat and from collisions with buildings and towers during migration. They are also occasionally caught as a cage bird.
According to the All About Birds resource, the total breeding population size of the Rose-breasted grosbeak is 4.1 million individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
Rose-breasted grosbeaks play an important role in the ecosystem they live in. Due to their diet habits, these birds help to disperse seeds and also control insect populations.