The bobolink (Dolichonyx oryzivorus) is a small New World blackbird and the only member of the genus Dolichonyx. An old name for this species is the "rice bird", from its tendency to feed on cultivated grains during winter and migration. The bobolink breeds in the summer in the United States and Canada, with most of the summer range in the northern U.S. Bobolinks winter in southern South America, primarily Paraguay, Argentina, and Bolivia. Bobolink numbers are rapidly declining due to factors such as agricultural intensification and habitat loss; they are considered threatened in Canada, and are at risk throughout their range.

The bobolink was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae. He placed it with the finches in the genus Fringilla and coined the binomial name Fringilla oryzivora. Linnaeus mainly based his account on "The Rice-Bird" that had been described and illustrated in 1729 by the English naturalist Mark Catesby in his book The Natural History of Carolina, Florida and the Bahama Islands. Linnaeus specified the type locality as "Cuba ... in Carolinam" but this was restricted to the state of South Carolina by the American Ornithologists' Union in 1931. The bobolink is now the only species placed in the genus Dolichonyx that was introduced in 1827 by the English zoologist William Swainson. The genus name combines the Ancient Greek δολιχος/dolikhos meaning "long" with ονυξ/onux, ονυχος/onukhos meaning "claw" or "nail". The specific epithet oryzivorus combines the Latin oryza meaning "rice" with -vorus meaning "eating". The English name "bobolink" is from Bob o' Lincoln, describing the call. The species is considered to be monotypic: no subspecies are recognised.

Measurements:

Adults are 16–18 cm (6.3–7.1 in) long with short finch-like bills and weigh about 28 g (1 oz). Adult males are mostly black with creamy napes and white scapulars, lower backs, and rumps. Adult females are mostly light brown with black streaks on the back and flanks, and dark stripes on the head; their wings and tails are darker.

The bobolink breeds in the summer in North America across much of southern Canada and the northern United States; from 1966 to 2015 the species experienced a greater than 1.5% annual population decrease throughout most of its breeding range, extending from the Midwestern United States to the Canadian Maritimes. The bobolink migrates long distances, wintering in southern South America. One bird was tracked migrating 12,000 mi (19,000 km) over the course of the year, often flying long distances up to 1,100 mi (1,800 km) in a single day, then stopping to recuperate for days or weeks.

Bobolinks often migrate in flocks, feeding on cultivated grains and rice, which leads to them being considered a pest by farmers in some areas. Although bobolinks migrate long distances, they have rarely been sighted in Europe — like many vagrants from the Americas, the majority of records are from the British Isles.

The species has been known in the southern United States as the "reedbird," or the "ricebird" from their consumption of large amounts of the grain from rice fields in South Carolina and the Gulf States during their southward migration in the fall. One of the species' main migration routes is through Jamaica, where they are called "butter-birds" and at least historically were collected as food, having fattened up on the aforementioned rice.

Bobolinks are the only species of land bird known to annually migrate through the Galápagos Islands, which are over 2,000 km from their primary migration route. A bobolink was collected in the Galápagos Islands by Charles Darwin in 1835. Bobolinks have been hypothesized to act as vectors for avian malaria-causing parasites arriving in the Islands. Additionally, bobolinks in the Galápagos have been found with seeds from Drymaria cordata, a plant native to the Galápagos but highly invasive elsewhere, entangled in their feathers, potentially spreading them to the mainland.