Myrmotherula assimilis
Silhouette: Sheatherius · PhyloPic
In 3 days ~10% in a week ~20%
The leaden antwren (Myrmotherula assimilis) is a species of bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is found in Bolivia, Brazil, Colombia, and Peru. The leaden antwren was described by the Austrian ornithologist August von Pelzeln in 1868 and given its current binomial name Myrmotherula assimilis.
The leaden antwren is 9 to 10.5 cm (3.5 to 4.1 in) long and weighs 8.2 to 10.5 g (0.29 to 0.37 oz). It is a small bird with a short tail. Adult males of the nominate subspecies have a medium gray crown, back, and rump with a hidden white patch between the shoulders. Their wing coverts are medium gray with white tips and their flight feathers are dusky. Their tail is gray. Their underparts are pale gray that is palest on the throat. Adult females have a medium brownish gray to olive gray crown, back, and rump with a hidden white patch between the shoulders. Their wings are olive brown with pale buff or whitish buff tips on the coverts. Their tail is gray or dusky. Their face is pale gray... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Anavilhanas National Park | 🇧🇷 Brazil | |
| 2 | Amacayacu National Natural Park | 🇨🇴 Colombia |
Rare
Under 5% of wildlife watchers report a Leaden Antwren sighting in Amacayacu National Natural Park on a given day, based on 26 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 283rd most-seen of the 436 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
March
In that month about 20% of wildlife watchers report a Leaden Antwren in Amacayacu National Natural Park on a given day, against under 5% in April and July–February, the lowest months. That is one of Amacayacu National Natural Park's wettest months, with about 390 mm of rain against 160 mm in August.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Leaden Antwren sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Leaden Antwren sightings, Amacayacu National Natural Park ranks 2nd at under 5%. The best odds are in Anavilhanas National Park (Brazil, about 30%).
Same genus: Myrmotherula
The closest relatives of the Leaden Antwren that you can see in Amacayacu National Natural Park (genus Myrmotherula, Typical Antwrens) are Pygmy Antwren (about 10%), White-flanked Antwren (about 10%) and Moustached Antwren (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Leaden Antwren is recorded against all the birds logged in Amacayacu National Natural Park (26 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
