About Spartonoica maluroides (Orbigny & Lafresnaye, 1837)
The bay-capped wren-spinetail, with the scientific name Spartonoica maluroides (Orbigny & Lafresnaye, 1837), measures 13 to 14.5 cm (5.1 to 5.7 in) in length and weighs approximately 10.5 g (0.37 oz). Males and females share identical plumage patterns. Adult individuals have a whitish supercilium on an otherwise sandy brown face, and a rufous crown. Their upperparts range from sandy brown to olive-brown, with bold black streaks across the nape and upper back. Their wings are brown, with cinnamon coloring at the base of the flight feathers. Their mostly brown tail is graduated with pointed feathers, and the central pair of tail feathers have some black markings. Their underparts are whitish, with a buff or cinnamon tinge on the breast, sides, and flanks. Their iris can be dull white, whitish, or pale bluish; their maxilla is blackish; their mandible is whitish to pinkish with a dark tip; and their legs and feet are light tan. Coastal and inland populations show only minor differences in size and plumage darkness, with very little genetic divergence between them. The species is distributed from extreme southern Brazil, south through Uruguay, into northern Argentina as far south as Río Negro Province. It has also been recorded as a non-breeding visitor in Paraguay. It inhabits reedbeds and sedges in freshwater, brackish, and saltwater marshes. Its elevational range extends from sea level to approximately 900 m (3,000 ft).
