Rusty Blackbird

The Rusty Blackbird (Euphagus carolinus) is a medium-sized songbird of the family Icteridae. Unique among North American blackbirds for its strong dependency on wooded wetlands, this species breeds across the expansive boreal forest of Canada and Alaska before migrating to the forested wetlands of the southeastern United States. Sadly, the Rusty Blackbird is also known for experiencing one of the most severe and perplexing population declines of any North American songbird, with populations dropping by an estimated 85% to 90% since the mid-20th century.

Identifying Rusty Blackbirds requires attention to seasonal plumage changes, body structure, and eye color.

Field Marks

• Eyes: Both adult males and females feature distinctive, pale straw-yellow eyes, which contrast sharply with their dark plumage.
• Breeding Male: Almost entirely glossy black with a subtle greenish or blue hue on the body, lacking the heavy iridescent purple sheen found on Brewer's Blackbirds.
• Non-breeding/Winter Male: Strikingly marked with extensive rusty-brown edges on the feathers of the back, crown, and breast, giving the bird its namesake 'rusty' appearance.
• Female: Overall slate-gray. In winter, females show rich rusted highlights on their upperparts and a bold, pale buff-yellow eyebrow (supercilium) contrasting with a dark gray eye patch.
• Bill and Silhouette: Features a slender, finely pointed bill that is straighter and narrower than that of a Red-winged Blackbird or Brown-headed Cowbird.

Similar Species

• Brewer's Blackbird: Breeding males have a stronger violet-purple iridescence on the head. Female Brewer's Blackbirds typically have dark brown eyes, whereas female Rusty Blackbirds have pale eyes. Brewer's also prefers drier, open habitats like agricultural fields and parking lots.
• Common Grackle: Significantly larger with a much longer, keel-shaped tail and a heavy, thick-based bill.
• Red-winged Blackbird: Lacks the pale yellow eye in all plumages. Females are heavily streaked overall and do not have the solid slate-gray or rusty-patterned plumage of the Rusty Blackbird.

Geographic Range and Migration

The Rusty Blackbird nesting grounds stretch across the boreal forest zone, spanning from Alaska across northern Canada to Newfoundland and New England. It is a migratory species, moving southeastward in autumn to spend the winter in the eastern and southern United States, particularly the Mississippi Valley and Atlantic coastal plains.

Habitat Preferences

Unlike many other blackbirds that thrive in open agricultural fields or suburban lawns, this species is highly dependent on wet, wooded environments:

• Breeding Habitat: Beaver ponds, bogs, fens, muskegs, and swampy edges of coniferous forests.
• Wintering Habitat: Bottomland hardwood forests, flooded swamps, cypress pools, and damp margins of rivers and creeks where leaf litter is submerged or saturated.

Feeding Ecology

Rusty Blackbirds are specialized ground-foragers with a distinct preference for shallow, standing water. They walk along the margins of pools, wading in up to their bellies, and flip over damp leaves, twigs, and debris to uncover hidden prey. Their diet is heavily dominated by insects during the breeding season (particularly aquatic dragonfly and damselfly larvae, beetles, and caddisflies) but shifts to seeds, waste grain, and pine mast during winter months.

Voice and Vocalizations

The song of the Rusty Blackbird is highly distinctive—a creaky, ascending metallic squeak followed by a higher-pitched buzz, often compared to the sound of a rusty metal hinge being opened ("koo-leee" or "shreee-leee"). Their call is a flat, dry, harsh "chack" or "tchuck," louder and lower than that of a Red-winged Blackbird.

Breeding and Nesting

Monogamous pairs form shortly after arriving on the breeding grounds. The female constructs a bulky, thick-walled cup nest using wet twigs, grass, lichens, and moss, cementing the structure with decaying vegetation or mud. To minimize land-based predation, the nest is typically situated low in a dense spruce, fir, or willow shrub directly over or adjacent to standing water. A typical clutch consists of 3 to 6 pale green or blue-green eggs, blotched with brown.