Pacific Antwren

The Pacific antwren, also known as the Pacific streaked antwren (Myrmotherula pacifica), is a diminutive bird, a member of the Thamnophilidae family, which encompasses the typical antbirds. This species is characterized by its small stature, measuring between 9 to 10 cm in length and weighing between 8.5 to 10 grams. The males are distinguished by their striking black and white streaked plumage, while the females exhibit a more subdued buff to cinnamon-rufous coloration with black streaks on the crown and nape.

Identification Tips

To identify the Pacific antwren, look for the male's black and white streaked face, white shoulder patch, and black tail with white edges. Females can be recognized by their buff to cinnamon-rufous face and lack of streaks on the underparts. Both sexes have a notably tiny tail and exhibit an active foraging behavior within dense foliage.

Habitat

The Pacific antwren inhabits the understorey and mid-storey of lowland and foothill evergreen forests, as well as shrubby secondary forests. It is often found in shrubby areas along watercourses and occasionally in gardens and plantations.

Distribution

This species is found from the Caribbean and Pacific slopes of Panama, extending into Colombia and reaching western Ecuador. Its elevation range is typically from sea level to about 800 meters, with some local variations.

Behaviour

The Pacific antwren is a year-round resident within its range. It forages mostly alone or in pairs, actively seeking prey among leaves and vine tangles. It seldom joins mixed-species feeding flocks and prefers dense foliage for foraging.

Song & calls

The song of the Pacific antwren is a fast, spritely chipper that rises slightly in pitch. Its calls include "chee-pu", "chee-cher", and a strident "chrreee-chrreee-chrreee-chrreee!".

Breeding

Breeding occurs between January and July in Panama, with an observed active nest in Colombia in March. The nest is a cup suspended in a branch fork, usually near the end and hidden in foliage. Clutch size is typically two eggs, but details on incubation and parental care are not fully documented.

Diet and Feeding

The diet consists primarily of arthropods, with a preference for insects and spiders. The Pacific antwren forages between 2 and 10 meters above ground, occasionally reaching up to 17 meters.

Conservation status

The IUCN has classified the Pacific antwren as Least Concern. It has a large range, an estimated population of at least 50,000 mature individuals, and is considered fairly common across its range. It occupies a variety of habitats, making it less sensitive to human disturbance than most antbirds.