チョコフエフキタイランチョウ 対 チャボウシクロフウキンチョウ

The most reliable field mark is the overall color pattern and crest: Choco Sirystes of all ages shows a black crown with a slight crest, pale gray back, and bold white edges on the wings, while Tawny-crested Tanager males are glossy black with a short, bright tawny crest, and females are dull olive-brown with no black crown. Choco Sirystes is notably larger and heavier-bodied than the tanager. In flight or perched, look for the Sirystes' white-edged wings and tail tips versus the tanager's plainer wings and, in males, a contrasting tawny crest. Juvenile Sirystes are similar to adults but with a buffy wash, while female tanagers are much duller and browner overall. Bill shape and size also differ: Sirystes has a stouter, flycatcher-like bill, while the tanager's is shorter and thinner.

1. Black Crown with Crest (Sirystes): Look for the black crown and slight crest on all Choco Sirystes, which is never shown by Tawny-crested Tanager of any age or sex. This is a key mark both perched and in flight.
2. Tawny Crest (Tanager Male): Adult male Tawny-crested Tanagers have a short, bright tawny to dark yellow crest, contrasting with their glossy black body. Females lack this crest entirely. The Sirystes' crest is black and less conspicuous.
3. Overall Size and Bulk: Choco Sirystes is much larger and heavier-bodied than the tanager. Use this when both species are seen in the same flock or with other birds for scale.
4. Bill Shape: Sirystes has a stouter, more robust flycatcher-type bill, while the tanager's bill is shorter and thinner, typical of tanagers. This is visible at close range or in good photos.
5. Wing Pattern (Sirystes): Sirystes shows wide white edges on the wing coverts and secondaries, visible both perched and in flight. The tanager's wings are dusky with only a small, often hidden, white patch at the bend (male only) and white underwing coverts (not visible unless wings are spread).
6. Tail Pattern: Sirystes has a dusky tail with grayish white tips, while the tanager's tail is dusky with no pale tips.
7. Underparts: Sirystes has grayish white to white underparts, clean and contrasting with the upperparts. Male tanagers are black below, females are olive-brown with a paler throat but never white.
8. Rump and Uppertail Coverts: Sirystes shows a white rump and dark uppertail coverts with white fringes; tanager lacks these contrasts.
9. Juvenile Plumage: Juvenile Sirystes are like adults but with a faint buffy tinge, still showing the black crown and white-edged wings. Juvenile tanagers (especially females) are dull olive-brown and lack any black or white crown, making them much plainer.
10. Sexual Dimorphism (Tanager): Only male Tawny-crested Tanagers are glossy black with a tawny crest; females are dull olive-brown. Sirystes shows no sexual dimorphism in plumage.
11. Leg and Iris Color: Both species have dark legs, but the tanager's iris is reddish brown, while Sirystes' is dark brown. This is subtle and rarely diagnostic in the field.
12. Behavior: Sirystes often perches upright and sallies for insects, typical of flycatchers. Tanagers are more active in foliage and less likely to sally from exposed perches.
13. Habitat Preference: In overlap zones, Sirystes is more likely in dense humid forest interiors, while tanagers may be found in a wider range of forest types, including edges and secondary growth.
14. Mixed Flocks: Both may join mixed-species flocks, but Sirystes tends to be more stationary and deliberate, tanagers more active and social.
15. Pitfalls: Female and juvenile tanagers are the most likely confusion risk with Sirystes due to their dull coloration, but they lack the black crown, white-edged wings, and white underparts of Sirystes. Always check for these marks before relying on overall color or size.

Choco Sirystes is significantly larger, measuring 17.5–19 cm in length and weighing 32–36 g, compared to the Tawny-crested Tanager's 14 cm length and 14–21 g weight [wikipedia][wikidata]. The Sirystes appears bulkier and more robust, while the tanager is noticeably smaller and lighter. This size difference is apparent in direct comparison or when seen with other birds for scale.

• Juveniles: Choco Sirystes juveniles resemble adults but have a faint buffy tinge; they still show the black crown, pale gray back, and white-edged wings. Tawny-crested Tanager juveniles are not described in detail, but female-like birds are dull olive-brown with dusky wings and tail, lacking any black crown or bold white in the wings.
• Adults: Choco Sirystes of both sexes have a black crown with a slight crest, slate gray face, pale gray nape and back, white rump, dark uppertail coverts with white fringes, dusky black wings with wide white edges on coverts and secondaries, dusky tail with grayish white tips, and grayish white to white underparts. Tawny-crested Tanager males are glossy black with a short, bright tawny to dark yellow crest, a small white patch at the wing bend (often hidden), and white underwing coverts; females are grayish brown on the head, dark olive-brown above, dusky wings and tail, and paler olive-brown underparts with a paler throat. The tanager's crest is variable in size and color but always present in males and absent in females. The Sirystes' wing and tail show more obvious white edging, especially in flight.

Choco Sirystes often joins mixed-species feeding flocks and uses flycatcher-like sallies from a perch to catch insects and fruit. Its behavior is typical of tyrant flycatchers: upright posture, frequent returns to the same perch, and sallying flights. Tawny-crested Tanager behavior is not described in detail here, but tanagers generally move more actively through foliage and are less likely to sally from exposed perches. Sirystes may appear more deliberate and stationary, while tanagers are more restless and social.

Both species overlap in Colombia, Ecuador, and Panama, but the Choco Sirystes is more restricted to humid Chocó lowland and foothill forests. The Tawny-crested Tanager ranges more widely, including into Central America (Costa Rica, Nicaragua, Honduras) and various forest types. In areas of overlap, both may occur in mixed flocks, but Sirystes is more likely in dense, humid forest interiors.