The Rusty Blackbird, Euphagus carolinus, is a medium-sized blackbird.

Adults have a pointed bill and a pale yellow eye. They have black plumage; the female is greyer. "Rusty" refers to the brownish winter plumage. They resemble the western member of the same genus, the Brewer's Blackbird; however, this bird has a longer bill and the male's head is iridescent green. The song resembles the grating of a rusty hinge.

Their breeding habitat is wet temperate coniferous forests and muskeg across Canada and Alaska. The cup nest is located in a tree or dense shrub, usually over water.

These birds migrate to the eastern and southeastern United States, into parts of the Grain Belt, sometimes straying into Mexico.

They forage on wet ground or in shallow water, mainly eating insects and some seeds. They will attack small passerine birds, and have been known to kill species as large as Common Snipe. They feed in flocks during migration, often joining other blackbirds.

Rusty Blackbirds have declined significantly in recent decades. The reasons are unclear, but habitat loss is likely a major contributor to the decline. Rarer than previously believed, it is uplisted from a species of Least Concern to Vulnerable status in the 2007 IUCN Red List.

Additionally, citizen science projects such as the North American Breeding Bird Survey and Christmas Bird Count have determined that Rusty Blackbirds have dropped 85%-98% in the past 40 years. This is very worrisome for many people, as scientists are desperately trying to figure out what exactly went wrong. Sighting submission services such as eBird are encouraging birders to keep track of Rusty Blackbirds.