Yellow-margined Flycatcher

Yellow-margined Flycatcher

Tolmomyias assimilis

Silhouette: Emily Willoughby · PhyloPic

Least ConcernNear ThreatenedVulnerableEndangeredCritically Endangered
Daily sighting probability <5% · Rare
at Yasuní National Park
165 Verified sightings at Yasuní National Park From 2019 to 2026
3,544 Verified sightings across all 32 parks From 2019 to 2026
August Best month highest sighting rate
☀️ Diurnal When it's spotted during daytime hours (6am–6pm)

About the Yellow-margined Flycatcher

The yellow-margined flatbill or Zimmer's flatbill (Tolmomyias assimilis) is a species of bird in the tyrant flycatcher family Tyrannidae. It is found in every mainland South American country except Argentina, Chile, Paraguay, and Uruguay.

The yellow-margined flatbill has a complicated taxonomic history. It was originally described as Rhynchocyclus assimilis. In the early twentieth century it was treated as a subspecies of the yellow-olive flatbill (now T. sulphurescens) but was separated by most authors starting in about 1940. As of 2025 it has eight subspecies. However, what is now the yellow-winged flatbill (T. flavotectus) was previously a ninth subspecies. It was separated starting in 2016 but the process continued until 2024. Confusingly, for a time T. flavotectus was called the yellow-margined flatbill.

The eight subspecies of the yellow-margined flatbill are: T. a. neglectus Zimmer, JT, 1939 T. a. examinatus (Chubb, C, 1920) T. a. obscuriceps Zimmer, JT, 1939 T. a. clarus Zimmer, JT, 1939 T. a. assimilis (Pelzeln, 1868)

T. a. sucunduri Whitney, Schunck, MA Rêgo & Silveira, 2013 T. a. paraensis Zimmer, JT, 1939 T. a. calamae Zimmer, JT, 1939 The... Wikipedia →

Closest Relatives at Yasuní National Park

Gray-crowned Flycatcher
LC

Gray-crowned Flycatcher

☀️ Diurnal Bird

Tolmomyias poliocephalus

Daily sighting probability ~10% · With luck
Yellow-breasted Flycatcher
LC

Yellow-breasted Flycatcher

☀️ Diurnal Bird

Tolmomyias flaviventris

Daily sighting probability ~10% · With luck
Orange-eyed Flycatcher
LC

Orange-eyed Flycatcher

☀️ Diurnal Bird

Tolmomyias traylori

Daily sighting probability <5% · Rare
Tropical Kingbird
LC

Tropical Kingbird

☀️ Diurnal Bird

Tyrannus melancholicus

Daily sighting probability ~50% · Likely
Great Kiskadee
LC

Great Kiskadee

☀️ Diurnal Bird

Pitangus sulphuratus

Daily sighting probability ~50% · Likely
Lesser Kiskadee

Lesser Kiskadee

☀️ Diurnal Bird

Pitangus lictor

Daily sighting probability ~30% · Possible
Boat-billed Flycatcher
LC

Boat-billed Flycatcher

☀️ Diurnal Bird

Megarynchus pitangua

Daily sighting probability ~30% · Possible
Social Flycatcher
LC

Social Flycatcher

☀️ Diurnal Bird

Myiozetetes similis

Daily sighting probability ~30% · Possible
Drab Water Tyrant
LC

Drab Water Tyrant

☀️ Diurnal Bird

Ochthornis littoralis

Daily sighting probability ~30% · Possible
Yellow-crowned Tyrannulet
LC

Yellow-crowned Tyrannulet

☀️ Diurnal Bird

Tyrannulus elatus

Daily sighting probability ~20% · Possible
Gray-capped Flycatcher
LC

Gray-capped Flycatcher

☀️ Diurnal Bird

Myiozetetes granadensis

Daily sighting probability ~20% · Possible
Bright-rumped Attila
LC

Bright-rumped Attila

☀️ Diurnal Bird

Attila spadiceus

Daily sighting probability ~20% · Possible

Global Distribution

Warmer areas are where this animal is recorded most often.

Parks Where Found

# Park Country Daily sighting probability
1 Soberanía National Park 🇵🇦 Panama
~10%
2 Darién National Park 🇵🇦 Panama
~10%
3 Utría National Natural Park 🇨🇴 Colombia
~10%
4 Parque Natural Metropolitano 🇵🇦 Panama
~10%
5 San Lorenzo Protected Forest 🇵🇦 Panama
~10%
6 Tambopata National Reserve 🇵🇪 Peru
~10%
7 Anavilhanas National Park 🇧🇷 Brazil
~10%
8 Chagres National Park 🇵🇦 Panama
~10%
9 Yasuní National Park 🇪🇨 Ecuador
<5%
10 Gandoca-Manzanillo Wildlife Refuge 🇨🇷 Costa Rica
<5%
11 Brownsberg Nature Park 🇸🇷 Suriname
<5%
12 Cuyabeno Wildlife Reserve 🇪🇨 Ecuador
<5%
13 Sierra de la Macarena National Park 🇨🇴 Colombia
<5%
14 Canaima National Park 🇻🇪 Venezuela
<5%
15 Madidi National Park 🇧🇴 Bolivia
<5%
16 Bastimentos Island National Marine Park 🇵🇦 Panama
<5%
17 Amacayacu National Natural Park 🇨🇴 Colombia
<5%
18 Braulio Carrillo National Park 🇨🇷 Costa Rica
<5%
19 Manu National Park 🇵🇪 Peru
<5%
20 Tortuguero National Park 🇨🇷 Costa Rica
<5%
21 La Amistad International Park (Panama) 🇵🇦 Panama
<5%
22 Cordillera Azul National Park 🇵🇪 Peru
<5%
23 Podocarpus National Park 🇪🇨 Ecuador
<5%
24 Farallones de Cali National Natural Park 🇨🇴 Colombia
<5%
25 Arenal Volcano National Park 🇨🇷 Costa Rica
<5%
26 Tapantí-Macizo de la Muerte National Park 🇨🇷 Costa Rica
<5%
27 Machalilla National Park 🇪🇨 Ecuador
Insufficient data
28 Noel Kempff Mercado National Park 🇧🇴 Bolivia
Insufficient data
29 Cahuita National Park 🇨🇷 Costa Rica
Insufficient data
30 Amboró National Park 🇧🇴 Bolivia
Insufficient data
31 Tayrona National Natural Park 🇨🇴 Colombia
Insufficient data
32 Tenorio Volcano National Park 🇨🇷 Costa Rica
Insufficient data

Quick answers

What are the chances of seeing a Yellow-margined Flycatcher in Yasuní National Park?

Under 5% of wildlife watchers report a Yellow-margined Flycatcher sighting in Yasuní National Park, based on 165 verified sightings from GBIF citizen-science data.

When is the best time to see Yellow-margined Flycatcher in Yasuní National Park?

August has the highest sighting rate for Yellow-margined Flycatcher in Yasuní National Park in our monthly data.

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