オウゴンチョウ 対 ズグロオウゴンチョウ

The most reliable field mark to separate Yellow-crowned Bishop from Golden-backed Bishop is the male's head pattern in breeding plumage: Yellow-crowned Bishop males show a brilliant yellow crown and forehead, while Golden-backed Bishop males lack this yellow crown entirely. Females and non-breeding males of both species are much duller and can be tricky to separate, but Yellow-crowned Bishop is notably smaller and lighter-bodied. If you see a bishop with a striking yellow crown, it's Yellow-crowned; if the yellow is restricted to the back and not the crown, it's Golden-backed. Size and structure also help: Golden-backed Bishop is much heavier and bulkier. Immature and non-breeding birds are best separated by size and subtle plumage differences, but confusion is likely without direct comparison.

1. Breeding male head pattern is the single best field mark: Yellow-crowned Bishop males have a brilliant yellow crown, forehead, and hindcrown; Golden-backed Bishop males never show yellow on the crown, only on the back. This mark is diagnostic in breeding season.
2. Body size and bulk: Golden-backed Bishop is much heavier and bulkier (25 g vs 14.5 g). If you see a bishop that looks notably chunky and large, especially in direct comparison, suspect Golden-backed.
3. Bill color in breeding males: Yellow-crowned Bishop males have a black bill in breeding season; outside breeding, the bill is horn-colored. Golden-backed's bill color is not specified but likely similar, so use with caution.
4. Female and non-breeding plumage: Both species are brown and streaked, but Yellow-crowned Bishop is smaller and more delicate. The underparts of Yellow-crowned are off-white with fine streaks; Golden-backed's are likely similar but on a larger, bulkier bird.
5. Yellow distribution: On Yellow-crowned, yellow is present on the crown, rump, and back (breeding males); on Golden-backed, yellow is restricted to the back, not the crown.
6. Flight and perched jizz: No distinctive wing or tail patterns are described for either species, so use overall size and color. Golden-backed will appear more robust in flight and when perched.
7. Leg and foot color: Both species have pinkish-brown legs and feet; not useful for separation.
8. Range and habitat: If seen outside western Angola or São Tomé, it is almost certainly not Golden-backed Bishop. Yellow-crowned is widespread and adaptable, often found in agricultural or wetland edges.
9. Seasonal confusion: In non-breeding season, males resemble females and are much duller; rely on size, structure, and subtle plumage differences.
10. No distinctive juvenile/immature wing pattern: Neither species shows unique upperwing or flight marks in immature plumages, so age-specific separation relies on size and overall coloration.
11. Shoulder patch: Yellow-crowned Bishop males have a yellow patch on the shoulder in breeding plumage; Golden-backed's shoulder color is not specified but is less likely to be as bright.
12. Rump color: Yellow-crowned Bishop males have a yellow rump in breeding plumage; check for this in good light.
13. Plumage confusion with other bishops: Yellow-crowned Bishop breeding males can resemble Yellow Bishop (Euplectes capensis), but that species is larger and lacks the yellow crown. Golden-backed is less likely to be confused with Yellow-crowned due to its restricted range and lack of yellow crown.
14. Bill shape: Both have short, conical bills typical of weavers; not useful for separation.
15. Community tip: When in doubt, focus on the presence or absence of yellow on the crown and the bird's overall size and bulk.

Golden-backed Bishop is significantly larger and heavier than Yellow-crowned Bishop. According to [wikidata], Golden-backed averages 25.0 g, while Yellow-crowned is only 14.5 g. In the field, this translates to a noticeably bulkier, more robust bird for Golden-backed, compared to the more delicate, sparrow-like Yellow-crowned. Both are small bishops, but the difference is substantial enough to be seen with experience, especially if both are present. Length is similar (Yellow-crowned: 95–105 mm), but Golden-backed's extra mass gives it a chunkier appearance.

Breeding males are most easily separated. Yellow-crowned Bishop males have a vivid yellow crown, forehead, and hindcrown, with black on the lower face, throat, breast, and belly, plus a yellow rump and back. Their wings and tail are brown. Golden-backed Bishop males, in contrast, lack the yellow crown entirely; their yellow is confined to the back, and the head is not as brightly marked. Non-breeding males and females of both species are much duller: Yellow-crowned Bishop females and non-breeding males are pale brown above with darker streaks and off-white underparts with fine streaking, while Golden-backed Bishop's equivalent plumages are not described in detail in the sources, but are likely similar to other Euplectes bishops—brownish and streaked, but larger and bulkier. No distinctive juvenile or immature upperwing patterns are described for either species, so flight views rely mainly on size and overall coloration. Bill color can help: breeding male Yellow-crowned has a black bill, turning horn-colored outside breeding; Golden-backed's bill color is not specified, but likely similar.

Both species are weavers and show similar behaviors typical of Euplectes bishops, such as perching conspicuously in grasslands and displaying in breeding season. No specific behavioral differences are described in the sources. Both may be seen in flocks outside the breeding season and are often associated with grassy or weedy habitats.

Yellow-crowned Bishop is widespread across sub-Saharan Africa and has been introduced to several regions outside its native range. It favors grasslands, marshy areas, and agricultural fields (especially wheat and sorghum), often near water. Golden-backed Bishop is much more restricted, found only in western Angola and São Tomé Island. If you are outside this limited range, a bishop is almost certainly not Golden-backed. Both species prefer grassy, open habitats, but range is a strong clue.