キバラブチタイランチョウ 対 ホオジロタイランチョウ

Juvenile Sulphur-bellied Flycatchers show strong cinnamon-buff edges on the wing coverts and secondaries, while juvenile Piratic Flycatchers have wide cinnamon edges on the coverts but lack the strong yellow underparts and streaking of Sulphur-bellied. Adults of both species are streaked below, but Sulphur-bellied is much larger, with a boldly streaked sulphur-yellow belly and a rufous tail, while Piratic is smaller, with a duller yellow wash below and a dark tail. Bill shape and overall structure also differ: Sulphur-bellied is bulkier and longer-billed, while Piratic is compact with a short, stubby bill. Focus on underpart color and streaking, tail color, and bill shape for the most reliable separation.

1. Juvenile wing pattern: Juvenile Sulphur-bellied shows strong cinnamon-buff edges on the wing coverts and secondaries; Piratic juveniles have wide cinnamon edges but also show rusty edges on the tail and paler, less streaked underparts. Use this in late summer and early fall.
2. Underpart color and streaking: Adult Sulphur-bellied has bright sulphur-yellow underparts with bold, coarse black streaks on the breast and flanks; Piratic is paler yellow below, with brownish or olive streaks that are usually finer and less extensive.
3. Throat pattern: Sulphur-bellied's throat is white with dusky streaks; Piratic's throat is plain white and unstreaked. This is a key mark at close range.
4. Tail color: Sulphur-bellied has a mostly cinnamon-rufous tail with dusky streaks; Piratic's tail is dusky brown or blackish brown, sometimes with lighter edges but never rufous overall.
5. Bill shape: Sulphur-bellied has a long, strong, and slightly hooked bill; Piratic's bill is short, wide, and stubby. Bill shape is often obvious in profile.
6. Crown and supercilium: Both species can show a partially hidden yellow crown patch as adults, but Sulphur-bellied's supercilium is pale hoary gray and more prominent, while Piratic's is dull whitish and wraps under the crown.
7. Facial pattern: Sulphur-bellied shows a strong dark mask through the lores and ear coverts; Piratic has dusky lores and ear coverts but a less defined mask, with white cheeks and a duller overall face.
8. Upperparts: Sulphur-bellied's upperparts are light olive with a buffy tinge and streaked; Piratic's are dark grayish brown or olive-brown with pale edges but less contrast.
9. Size and structure: Sulphur-bellied is much larger and bulkier, with a longer tail and more upright stance; Piratic is compact and smaller overall.
10. Juvenile crown: Juvenile Sulphur-bellied lacks the yellow crown patch and is more buffy above; juvenile Piratic has light cinnamon tips on the crown feathers and a buffy supercilium.
11. Tail edges in juveniles: Juvenile Piratic shows rusty edges on the tail feathers, a subtle but sometimes visible mark.
12. Leg and iris color: Both have dusky legs and brown irises; not useful for separation.
13. Seasonal context: In Mexico and Central America, Piratic is absent or rare from late September through January; Sulphur-bellied is migratory but overlaps in timing. Check local abundance on eBird if unsure.
14. Habitat context: Sulphur-bellied prefers riparian and montane forests, Piratic is more generalist and found in a wider range of wooded habitats.
15. Vocalizations: Not described in the notes; do not rely on voice for separation based on current information.

Sulphur-bellied Flycatcher is nearly twice as heavy (47 g vs. 23 g) and noticeably longer (about 20 cm vs. 14.5–17 cm) than Piratic Flycatcher. In the field, Sulphur-bellied appears large, robust, and long-tailed, while Piratic is distinctly smaller, more compact, and short-billed. This size difference is often obvious if both are seen in the same area, but can be misleading if seen alone or at a distance.

Juvenile Sulphur-bellied Flycatchers have little or no yellow crown patch, a strong brownish-buffy tinge to the upperparts, and cinnamon-buff edges on the wing coverts and secondaries. Juvenile Piratic Flycatchers lack any yellow on the crown, have light cinnamon tips on the crown feathers, a buffy supercilium, wide cinnamon edges on the wing coverts, rusty edges on the tail, and paler underparts with few or no streaks. In adults, Sulphur-bellied shows a pale hoary gray forecrown, a bold dark mask, a rufous tail with dusky streaks, and bright sulphur-yellow underparts with heavy black streaking on the breast and flanks. Piratic adults have a blackish crown with a partially hidden yellow patch, a wide dull whitish supercilium, dark grayish brown upperparts with pale edges, a dusky brown tail, and pale yellowish underparts with brownish or olive streaks on the breast and flanks, but these streaks are typically less bold than in Sulphur-bellied. The throat of Sulphur-bellied is streaked, while Piratic's is plain white. The tail of Sulphur-bellied is mostly cinnamon-rufous, contrasting with the dark tail of Piratic.

Both species are arboreal flycatchers, often perching at mid to upper levels in trees. Sulphur-bellied tends to appear more robust and upright, often sallying from prominent perches. Piratic Flycatcher is more compact and may appear more furtive, sometimes associating with mixed flocks. Both sally for insects and may glean fruit, but differences in behavior are subtle and not strongly diagnostic in the field.

Sulphur-bellied Flycatcher is typically found from southern Arizona south to Bolivia, favoring forest edges, riparian woodlands, and semi-open areas with large trees. Piratic Flycatcher has a broader range, occurring from Mexico through most of South America (except Chile), and is also found in a variety of wooded habitats, including second growth, plantations, and forest edges. Both may overlap in Central and northern South America, but Sulphur-bellied is more tied to riparian and montane habitats, while Piratic is more generalist.