Bay-capped Wren-Spinetail
Spartonoica maluroides
Small, with a long spiky tail. Has a brown-streaked black back contrasting with a cinnamon crown and pale underparts. Note the pale eyebrow. Found in well-vegetated marshes and wet areas with tall grass. The song is an insect-like buzzy trill.
Identification
The bay-capped wren-spinetail is 13 to 14.5 cm (5.1 to 5.7 in) long and weighs about 10.5 g (0.37 oz). The sexes have the same plumage. Adults have a whitish supercilium on an otherwise sandy brown face. Their crown is rufous. Their upperparts are sandy brown to olive-brown with bold black streaks on the nape and upper back. Their wings are brown with cinnamon at the base of the flight feathers. Their tail is mostly brown and graduated with pointed feathers; the central pair have some black. Their underparts are whitish with a buff or cinnamon tinge on the breast, sides, and flanks. Their iris is dull white, whitish, or pale bluish, their maxilla blackish, their mandible whitish to pinkish with a dark tip, and their legs and feet light tan. There are some minor differences in size and darkness of plumage, but little genetic divergence, between coastal and inland populations.
Taxonomy
The bay-capped wren-spinetail is the only member of genus Spartonoica and has no subspecies.<p>The bay-capped wren-spinetail was originally described as Synallaxis maluroides. It was later placed in genus Asthenes but has been recognized in Spartonoica starting in 1950. Genetic data show that it is not closely related to genus Asthenes but instead is sister to the cachalotes of genus Pseudoseisura.
- Scientific name
- Spartonoica maluroides
- Authority
- (d'Orbigny & Lafresnaye, 1837)
- Order
- Passeriformes
- Family
- Furnariidae
- Genus
- Spartonoica
Range and habitat
The bay-capped wren-spinetail is found from extreme southern Brazil south through Uruguay into northern Argentina as far south as Río Negro Province. It also has occurred as a non-breeder in Paraguay. It inhabits reedbeds and sedges in freshwater, brackish, and saltwater marshes. In elevation it ranges from sea level to about 900 m (3,000 ft).
- Migration
- Resident species
Behavior
The bay-capped wren-spinetail's movements have not been fully defined. It appears to be mostly resident but the species has been noted as far north as Paraguay in the non-breeding season.<p>The bay-capped wren-spinetail feeds on invertebrates, mostly insects and spiders. It usually forages alone, gleaning from marsh grasses and sedges. There is some evidence that pairs that nest in salt marshes preferentially feed in freshwater marshes.<p>In Argentina the bay-capped wren-spinetail breeds between September and February. The species is monogamous, and both sexes build the nest, incubate the eggs, and brood and feed nestlings. The nest is an open cup (uniquely among furnariids) built of twigs and grass and placed low to the ground deep inside marsh vegetation. The clutch size is two to four eggs. The incubation period is about 13 days and fledging occurs 11 to 14 days after hatch.<p>The bay-capped wren-spinetail's primary song is "a grasshopper-like buzz, long and tuneless, rising and falling away". It has other vocalizations whose purposes have not been defined.
Conservation
- Population trend
- declining
Photos
Distribution
Bird Calls
Other Birds
Mouse-colored Penduline-Tit
Anthoscopus musculus
A tiny drab bird with a sharp bill. Note gray back, whitish underparts, and faintly black-speckled forehead. Generally uncommon in dry savanna and thornscrub, usually found in pairs or small flocks. Similar to Sennar and African Penduline-Tits, but grayer on the back and paler below. Can also be mistaken for Yellow-bellied or Yellow-vented Eremomelas, but has a shorter and thinner bill and no yellow on the underparts. Vocalizations include high-pitched “sit” notes and long trills.
Hoffmann's Woodpecker
Melanerpes hoffmannii
Medium-sized woodpecker with bold black-and-white barring on back and a cream-colored belly. A patch of yellow on the lower belly can be difficult to see. Male has red crown and yellow nape. Female lacks red crown. Distinctive in range, but hybridizes with Red-crowned Woodpecker; hybrids best left unidentified. Found in open woodland, edges, and gardens.
Venezuelan Sylph
Aglaiocercus berlepschi
Unmistakable, long-tailed hummingbird with straight, short bill. Male has very long, brilliant blue tail and iridescent blue throat; female very different, with shorter, white-tipped tail and whitish underparts. Found alone inside humid forests or edges at low to mid heights in montane regions. Typical vocalizations are electric and short, repeated constantly. No similar species in its very limited range, though male very similar to more widespread Long-tailed Sylph. Endemic to the Turimiquire region of northeastern Venezuela.
Start Your Bird Watching Journey
Identify a bird outdoors and keep the field guide close for your next observation.