Southern Nightingale-Wren

The Southern Nightingale-Wren, also known as the Scaly-breasted Wren, is a diminutive bird with a length of approximately 11 cm. The males of this species typically weigh between 18.2 to 22 grams, while the females are slightly lighter, ranging from 17 to 18 grams. The adult's plumage is characterized by a dull gray-brown face, a deep chocolate-brown crown, and upperparts with a subtle reddish hue on the rump. A very short dark chocolate tail complements their appearance. The chin, chest, and upper belly exhibit a white coloration with black scalloping on the chest's sides, transitioning to dark chocolate on the lower flanks and belly. Juveniles share a similar color scheme but with additional dark barring on the crown and back, as well as dark brown feather tips on the underside.

Identification Tips

To identify the Southern Nightingale-Wren, look for the distinctive scaly markings on the underparts, particularly in the subspecies M. m. squamulatus and M. m. taeniatus. The latter also has a more pronounced reddish tinge on the upperparts and blackish barring below. M. m. corrasus is notable for its purer white underside with narrow dark bars, while M. m. occidentalis features a longer and thinner bill, darker upperparts and flanks, and broad dark bars on its abdomen. M. m. luscinia is distinguished by a pale gray throat that darkens to brownish gray on the breast and belly.

Habitat

This species thrives in the lower strata of dense, humid tropical forests. It can be found from sea level up to elevations of 1,700 meters in Costa Rica, 1,400 meters in Colombia, and 1,800 meters in Venezuela, with an isolated record at 3,100 meters in Panama.

Distribution

The Southern Nightingale-Wren's range extends across various countries in South and Central America. Subspecies are distributed as follows: M. m. luscinia in central Costa Rica to eastern Panama, M. m. corrasus in northern Colombia's Santa Marta region, M. m. squamulatus in northern Colombia and northern Venezuela, M. m. occidentalis in western Colombia and northwestern Ecuador, M. m. taeniatus in western Ecuador, and M. m. marginatus throughout Amazonia.

Behaviour

Typically foraging alone, the Southern Nightingale-Wren is a ground-dweller and understory inhabitant. While it has been observed following army ant swarms in Central America, this behavior is not a routine part of its feeding habits.

Song & calls

The vocalizations of the Southern Nightingale-Wren vary geographically. In Central America to western Amazonia, the song consists of long, complex series of short notes followed by several whistles. In contrast, the songs heard in Peru and Bolivia are composed of clear, pure notes delivered seemingly at random, with variations in pitch, length, and volume.

Breeding

Breeding activity for this species is almost year-round, with most data coming from Panama. Nests are typically constructed of leaves at the end of burrows likely excavated by other bird species. Descriptions of two nests revealed one with two eggs and another with three.

Similar Species

The Southern Nightingale-Wren can be confused with its close relative, the Northern Nightingale-Wren (Microcerculus philomela), from which it was once considered conspecific. However, differences in vocalizations and subtle plumage variations can aid in distinguishing between the two.

Diet and Feeding

The diet of the Southern Nightingale-Wren is not well-documented, but its foraging behavior suggests a diet that includes insects and other small invertebrates.

Conservation status

The IUCN has classified the Southern Nightingale-Wren as Least Concern. The species is considered well-distributed within its range and is present in several protected areas and national parks.