Yellow-olive Flatbill Tolmomyias sulphurescens Scientific name definitions

The Yellow-olive Flycatcher has a wide distribution, ranging from southern Mexico south to northeastern Argentina; across this large region, it is a resident in a variety of habitats, but always is associated with forest and forest edge.  The Yellow-olive Flycatcher has a broad bill; a gray or dark olive crown; and dark auriculars, which usually surround a paler central spot. There are at least 16 subspecies of Yellow-olive Flycatcher, which exhibit subtle variations on this basic appearance; these subspecies also often differ in voice and to sometimes in habitat, and may some day be shown to l represent a dozen or more full species.  These flycatchers forage singly or in pairs, and occasionally with mixed species flocks in the lower and mid-levels of forests.  The diet of the Yellow-olive Flycatcher is predominantly insects which it takes by slowly and deliberately searching foliage for prey, and then making a short sally or quick upward strike. The nests of Yellow-olive Flycatchers are pear-shaped bags made out of rootlets, fungal rhizomes and grass, regularly near an active wasp's nest.

13–15·5 cm; 14·5–15·2 g. Nominate race has dark olive crown, narrow whitish supraloral and eyering, pale olive auriculars with dusky patch towards rear; nape dark olive, upperparts olive-green; wings dusky or blackish, two yellowish-olive wingbars, yellowish margins of remiges; pale greenish-grey throat, becoming greenish-olive on breast and flanks, bright yellow on belly and undertail-coverts; iris variable, typically pale brown to pale grey; bill wide and flat, upper mandible black, lower mandible pale grey to pale pinkish; legs grey. Sexes similar. Juvenile is paler below, white eyering broken, dark brown or olive iris becoming paler with maturity.

Taxonomy requires further resolution. Regional differences in voice, plumage and eye color suggest that races might represent more than one species; some plumage variation appears clinal but clines discordant; several races dubious, particularly within South America.

Subspecies vary in extent of olive or gray on crown and throat, general brightness of green on back and yellow on belly, also iris color, although differences often quite subtle. Southern subspecies (pallescens and grisescens) have darker olive crown than northern subspecies.

Sixteen subspecies tentatively recognized.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Gray-headed) Tolmomyias sulphurescens cinereiceps Scientific name definitions

• eBird map
• 149 photos
• 37 recordings

Distribution

S Mexico (S Veracruz and N and SE Oaxaca E to Yucatán Peninsula) S to Costa Rica.

Identification Summary

Light-gray crown, no dusky auricular mark, cheeks and throat pale gray, belly pale yellow, iris whitish to pale yellow.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Yellow-olive) Tolmomyias sulphurescens flavoolivaceus Scientific name definitions

• eBird map
• 50 photos
• 8 recordings

Distribution

W Panama (Chiriquí, Colón) to NW Colombia (SW Bolívar).

Identification Summary

Rather small, has crown and throat more green, slight auricular mark, bright yellow belly.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (asemus) Tolmomyias sulphurescens asemus Scientific name definitions

• eBird map
• 25 photos
• 2 recordings

Distribution

W and C Colombia (Chocó to SW Cauca; upper Cauca Valley and Magdalena Valley in S Huila).

Identification Summary

Gray crown, dull gray throat and breast, paler dull yellow belly.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (confusus) Tolmomyias sulphurescens confusus Scientific name definitions

• eBird map
• 9 photos
• 7 recordings

Distribution

SW Venezuela (Táchira, W Apure), C and E Colombia (Magdalena Valley and E slope of E Andes) and NE Ecuador (W Sucumbíos, Napo).

Identification Summary

Transitional between W & N subspecies, with medium-gray crown, dull olive breast, medium-yellow belly.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (exortivus) Tolmomyias sulphurescens exortivus Scientific name definitions

• eBird map
• 38 photos
• 18 recordings

Distribution

NE Colombia (Sucre to Guajira and Cesar) and N Venezuela (mainly N of Orinoco, E to Sucre and Monagas).

Identification Summary

Olive crown with slight gray tinge, gray chin, dull olive breast, medium-yellow belly .

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Trinidad) Tolmomyias sulphurescens berlepschi Scientific name definitions

• eBird map
• 0 photos
• 0 recordings

Distribution

Trinidad.

Identification Summary

Resembles exortivus, but slightly duller yellow below.

---

EBIRD GROUP (POLYTYPIC)

Yellow-olive Flatbill (Guianan) Tolmomyias sulphurescens cherriei/duidae

• eBird map
• 8 photos
• 10 recordings

---

SUBSPECIES

Tolmomyias sulphurescens cherriei Scientific name definitions

Distribution

E Venezuela (Delta Amacuro and N Bolívar), the Guianas and N Brazil (upper R Branco and Amapá).

Identification Summary

Resembles exortivus, but slightly duller yellow below.

---

SUBSPECIES

Tolmomyias sulphurescens duidae Scientific name definitions

Distribution

S Venezuela (Amazonas, S Bolívar) and NW Brazil (N Amazonas perhaps to W Pará).

Identification Summary

Similar to cherriei, but darker olive breast and crown.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Equatorial) Tolmomyias sulphurescens aequatorialis Scientific name definitions

• eBird map
• 29 photos
• 12 recordings

Distribution

W Ecuador (S from Esmeraldas) and NW Peru (Tumbes, Piura).

Identification Summary

aequatorialis has dark gray crown, dull yellow-green breast , dark iris.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Andes) Tolmomyias sulphurescens peruvianus Scientific name definitions

• eBird map
• 8 photos
• 12 recordings

Distribution

SE Ecuador (S from W Morona-Santiago) and N and C Peru (Amazonas, S San Martín, E Pasco, Junín).

Identification Summary

Rather dark gray crown, more distinct auricular patch, pale green-gray throat, dull olive breast, bright yellow belly, usually dark iris.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Riverine) Tolmomyias sulphurescens insignis Scientific name definitions

• eBird map
• 8 photos
• 13 recordings

Distribution

NE Peru (along S bank of Amazon and lower R Ucayali, in Loreto) and NW Brazil (S of Amazon, from R Juruá E to R Jamundá and R Madeira; N of Amazon, from lower R Negro to R Nhamundá).

Identification Summary

Olive-gray crown, duller underparts than peruvianus, usually pale iris.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Para) Tolmomyias sulphurescens mixtus Scientific name definitions

• eBird map
• 15 photos
• 6 recordings

Distribution

NC Brazil (E Pará, NW Maranhão).

Identification Summary

Appears to be somewhat transitional, has medium-yellow belly (as N group) and darker crown (as S group).

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (inornatus) Tolmomyias sulphurescens inornatus Scientific name definitions

• eBird map
• 0 photos
• 1 recordings

Distribution

SE Peru (N Puno).

Identification Summary

Very like insignis but less olive on crown, slightly duller below.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Mato Grosso) Tolmomyias sulphurescens pallescens Scientific name definitions

• eBird map
• 36 photos
• 57 recordings

Distribution

C, S and E Brazil (S Maranhão, Piauí and Paraíba S to Mato Grosso, Bahia and possibly W Minas Gerais) S to Bolivia (Beni S to Tarija) and N Argentina (S to Tucumán).

Identification Summary

Darker olive crown, lores and cheeks pale, brighter green on back, pale green-gray throat, greener breast, bright yellow belly, grayish iris, closely resembles nominate.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (grisescens) Tolmomyias sulphurescens grisescens Scientific name definitions

• eBird map
• 0 photos
• 4 recordings

Distribution

C Paraguay and N Argentina (E Chaco and Formosa, N Santa Fe).

Identification Summary

Darker olive crown, lores and cheeks pale, brighter green on back, pale green-gray throat, greener breast, bright yellow belly, grayish iris, closely resembles nominate.

---

EBIRD GROUP (MONOTYPIC)

Yellow-olive Flatbill (Sooretama) Tolmomyias sulphurescens sulphurescens Scientific name definitions

• eBird map
• 64 photos
• 67 recordings

Distribution

E Paraguay, NE Argentina (Misiones) and SE Brazil (E Minas Gerais and Espírito Santo S to Rio Grande do Sul).

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Wide variety of dry to humid forest habitats, including borders of humid and montane forests, and dry, deciduous and gallery forests, isolated woodlots, shady plantations, and tall secondary growth; inhabits river islands and riparian habitats in Amazonia and S Venezuela. In Surinam, common in wooded sand ridges in coastal region, savanna forest and interior. Generally does not occur in humid lowland forest (terra firme), where replaced by T. assimilis and T. poliocephalus (Costa Rica); where these congeners absent (SE Brazil, and E slope of Andes in Ecuador and Peru), present species does inhabit tall humid forest. Mostly lowlands below 1500 m, smaller numbers on Andean slopes to c. 1800 m (900–1700 m in W Ecuador) and to 1900 m N of Orinoco (Venezuela); to 1200 m in Mexico.

Resident.

Food insects, including beetles (Coleoptera), ants (Hymenoptera), homopteran bugs; recorded prey include beetles of family Scolytidae. Small berries also occasionally taken. Forages singly or in pairs, alone or with mixed-species flocks, inside crowns and at lower and middle levels of forest. Perches with more upright posture than congeners, rarely cocks tail. Slowly and deliberately searches foliage for prey, then makes short (up to c. 2 m) sallies, upward strikes, hover-gleans, perch -gleans and aerial chases to capture prey, often from undersides of leaves, then dropping down or continuing to new perch. In Costa Rica, sometimes picks at bare branches.

Song highly variable geographically, e.g. a series of 2–6 sharp or buzzy high notes, “dzeeyp, dzyeep, dzeep”, sometimes with pause after first note, becoming sharper with each repetition, like that of T. assimilis but less nasal; in Venezuela, similar buzzy nasal “ps ps psst psst PSST” given N of Orinoco, whereas, S of river, typically a sharp “spik spik” with pause of 1–3 seconds between notes, or several “spik” notes in long irregular sequence; song W of Andes in Ecuador (aequatorialis) a thin and well-enunciated series of quick notes as ‘psee-pset-pset-pset’, E of Andes the notes a little longer, e.g. ‘swit-swit-swit-swit-swit’; in all areas often a long pause between songs. In Panama, call thin, usually consists of 1–2 sibilant notes, “dzz”, “dzz” or “tsit, tsit”, sometimes followed by fast musical rattle. Voice of nominate race described as a squeaky whistle, “sheet, shi-eet”, given three times.

Apr–Jun in Costa Rica, Apr–Jul in Trinidad and Jan–Jun in N Colombia. Male courtship displays involve trembling with wings stretched. Nest a pear-shaped bag made of black rootlets and fungal rhizomorphs, sometimes mixed with grass and cobwebs, composed of roof, chamber (in form of a bag), and downward-pointing perpendicular “chimney” as entrance, 1·5–11 m up and often hung from exposed branch or vine, often on woodland edge, over stream or roadside, regularly near wasp nest; frequently nests in bull’s horn acacia (Acacia) in Costa Rica; nest also used as a dormitory. Clutch 2–3 eggs; in Costa Rica, incubation by female, period 17–18 days, chicks brooded only by female, fed by both parents, nestling period 22–24 days.

Not globally threatened (Least Concern). Fairly common to abundant in most of range, though somewhat local on parts of E slope of Andes. The most widespread member of genus. Occurs in numerous national parks and other protected areas. Given its tolerance of wide variety of wooded habitats, including converted habitat, and its large range, this species is considered unlikely to become threatened in near future.