アカバネオタテドリ 対 ワキアカオタテドリ

The most reliable field mark between White-throated Tapaculo and Ochre-flanked Tapaculo is the bold white supercilium and white throat of the former, versus the ochre (tawny) flanks and clay-brown vent of the latter. Juvenile plumage is a potential pitfall, as both species are barred throughout at this age, but the color and distribution of barring and overall tones differ. White-throated Tapaculo is notably larger and bulkier, with a cinnamon forehead and more brownish upperparts, while Ochre-flanked Tapaculo is smaller, darker gray above, and has a unique 'Roman nose' profile. Careful attention to underpart patterning, face, and size will separate them in most field situations.

1. Juvenile barring: Both species' juveniles are barred all over, but Ochre-flanked Tapaculo juveniles have cinnamon to rufous barring over a dusky gray base, while White-throated Tapaculo juveniles are paler with more cinnamon tones and less overall contrast.
2. Supercilium and throat: White-throated Tapaculo of all ages (except possibly very young juveniles) shows a bold white supercilium and a white throat—these are absent in Ochre-flanked Tapaculo.
3. Flank and vent color: Ochre-flanked Tapaculo adults have distinctive tawny-brown (ochre) flanks and a clay-brown vent, setting them apart from the barred, paler underparts of White-throated Tapaculo.
4. Forehead color: White-throated Tapaculo has a cinnamon forehead, which is not seen in Ochre-flanked.
5. Upperparts tone: White-throated Tapaculo is gray-brown above (with S. a. atacamae paler and grayer), while Ochre-flanked Tapaculo is dark gray above.
6. Underpart barring: White-throated Tapaculo adults have dark brown barring across most of the underparts, while Ochre-flanked Tapaculo adults have plain gray underparts with no barring, except in juveniles.
7. Face shape: Ochre-flanked Tapaculo has a 'Roman nose'—a sloping, prominent facial profile—unusual for tapaculos and not present in White-throated.
8. Size and structure: White-throated Tapaculo is larger (19 cm vs. 14.5 cm) and bulkier, with a longer tail; Ochre-flanked is compact and short-tailed.
9. Rump pattern: White-throated Tapaculo shows lightly barred rump; Ochre-flanked Tapaculo's rump is not specifically described as barred.
10. Regional context: If in western Argentina, only Ochre-flanked Tapaculo is possible. In central Chile, both may occur, so plumage and structure are critical.
11. Subspecies confusion: S. a. atacamae (White-throated) is paler and grayer, but still has the white supercilium and throat, which Ochre-flanked never shows.
12. Perched vs. moving views: The white throat and supercilium of White-throated Tapaculo are often visible even in brief views; the ochre flanks of Ochre-flanked may be best seen when the bird is moving or flicking its wings.
13. Barred juveniles in flight: If you see a small, barred tapaculo in Chilean forests, check for the base color (dusky gray for Ochre-flanked, paler cinnamon for White-throated) and look for any hint of ochre on the flanks or white on the face.
14. Sex differences: No sex-specific plumage differences are described for either species, so all field marks apply to both sexes.
15. Voice: Not described in the notes, so do not rely on vocalizations for separation in this context.

White-throated Tapaculo is significantly larger, measuring about 19 cm in length, while Ochre-flanked Tapaculo is only 14.5 cm. The Ochre-flanked is also lighter, with adult body mass around 34.5 g (Wikidata), while White-throated Tapaculo is bulkier (exact mass not given, but implied by length and structure). In the field, White-throated Tapaculo appears more robust and longer-tailed, while Ochre-flanked Tapaculo is compact and short-tailed.

Juveniles of both species are barred throughout, but White-throated Tapaculo juveniles show overall barring with a paler, more cinnamon wash, while Ochre-flanked Tapaculo juveniles have cinnamon to rufous barring over a dusky gray base. For adults, White-throated Tapaculo shows a bold white supercilium, white throat, cinnamon forehead, gray-brown upperparts, and underparts with dark brown barring over whitish to pale cinnamon. Its rump is lightly barred. Ochre-flanked Tapaculo adults are dark gray above, paler gray on the underparts to the abdomen, with a clay-brown (ochre) vent and distinct tawny-brown flanks. The face profile of Ochre-flanked is distinctive, with a sloping 'Roman nose,' unlike the more typical tapaculo face of White-throated. The subspecies S. a. atacamae is paler and grayer, but still shows the white supercilium and throat.

White-throated Tapaculo is endemic to Chile, while Ochre-flanked Tapaculo is found in south-central Chile and adjacent western Argentina. Their ranges overlap in parts of Chile, but Ochre-flanked is more likely in southern and Andean forests, whereas White-throated is restricted to Chilean habitats. Habitat alone is not always diagnostic, but can support identification if the location is known.