Habitat
Largely middle-aged Cecropia trees that occupy a particular successional stage following tall cane Gynerium and preceding figs Ficus. From sea-level - 150 m.
North-eastern Peru on banks of lower R Napo (sightings to 50 km or more above mouth) and banks of R Amazon (vicinity of Iquitos), eastern in Brazil to vicinity of R Jamunda (R Nhamundá); isolated record near junction of R Beni and R Iténez (in Brazil known as R Guaporé), Bolivia.
 
Population
Estimated population is unknown (2010).
Voice
A rapid series of high-pitched squeaky chip notes sustained for up to 15 seconds or more, considerably longer and more rapid than the song of Bicolored Conebill (Conirostrum bicolor). Calls are weak and easily overlooked, and include a high 'teep' and 'ti-ti-ti'.
Pearly-breasted Conebill (Conirostrum margaritae) [XC28166]
by Peter Boesman from Ceiba Tops, Loreto, Peru (song)
Pearly-breasted Conebill (Conirostrum margaritae) [XC270663]
by Joseph Tobias and Nathalie Seddon from Padre Island near Cumaceba lodge, Loreto, Peru (song)
Subspecies
Genus has sometimes been placed in Coerebidae or Parulidae, but molecular-genetic data indicate that it belongs in present family, with Oreomanes as sister-group. This species was originally placed in genus Ateleodacnis, and some taxonomists argue that it, along with the other lowland conebills (Chestnut-vented Conebill (Conirostrum speciosum), White-eared Conebill (Conirostrum leucogenys) and Bicolored Conebill (Conirostrum bicolor)), should be returned to that genus. As a group they are morphologically quite distinct from most highland members of present genus.
No subspecies.
Similar Species
Very like Bicolored Conebill (Conirostrum bicolor), but slightly paler grey above and lacking buff tones below.
References
See References.