African Black Duck vs Steller's Eider
Anas sparsa comparado com Polysticta stelleri
Side-by-Side Comparison
| Atributo | African Black Duck | Steller's Eider |
|---|---|---|
| Nome científico | Anas sparsa | Polysticta stelleri |
| Ordem | Anseriformes | Anseriformes |
| Família | Anatidae | Anatidae |
| Estado de conservação | Least Concern | Vulnerable |
| Comprimento | — | — |
| Envergadura | 49,5 cm (19.5 in) | 40,7 cm (16.0 in) |
| Peso | 996,8333333333334 g (35.16 oz) | 815,75 g (28.77 oz) |
| Dieta | Eats molluscs, crustaceans, and aquatic invertebrates; dives in coastal and freshwater habitats; diet heavier in … | Eats molluscs, crustaceans, and aquatic invertebrates; dives in shallow coastal and estuarine habitats; diet invertebrate-dominated. |
| Tamanho da postura | 4-9 | 3-10 |
| Population Trend | — | — |
Habitat Comparison
African Black Duck
Fast-flowing rocky rivers and streams, mountain gorges, and waterfalls from sea level to 4,000 m across sub-Saharan Africa from Ethiopia and Kenya south to the Cape. Requires clear turbulent water with boulders.
Steller's Eider
Breeds on low-lying coastal tundra in Arctic Russia and occasionally Alaska. Winters on shallow rocky sea coasts, kelp beds, and sheltered bays in the Baltic Sea and Pacific coast of Alaska. Listed as Vulnerable.
Song & Call Comparison
African Black Duck
Produces a harsh, resonant quacking call; alarm is a loud, emphatic quack repeated rapidly. Both sexes call with strong quacking; pairs duet with synchronized calls along African rivers.
Steller's Eider
Male produces a low, soft cooing note; female gives a guttural, grunting purr. Quieter than other eiders; the male's gentle cooing is unlike the louder calls of the Common Eider.
Geographic Range & Migration
African Black Duck
Resident across South and Southeast Asia, from India to southern China and the Philippines. Non-migratory in most of its range.
Steller's Eider
Breeds in boreal Canada and Alaska; winters along Pacific and Atlantic coasts and on large interior lakes of the US.
Estado de conservação
African Black Duck
Steller's Eider
How to Tell Them Apart
African Black Duck
Dark blackish-brown plumage with bold white spots on back and scapulars. Iridescent blue-green speculum with white borders. Head dark with pale spots. Bill and legs dark gray. Sexes similar. Fast-flowing …
Steller's Eider
Males have white head with green nape spot, black eye patch and chin; orange-buff underparts; black back with white wing patches. Females mottled dark brown with blue speculum bordered white. …
About These Birds
African Black Duck
O pato-negro-africano é um pato dabbling de tamanho médio das correntes de montanha e rios do leste e sul da África. Tem plumagem preta com barras brancas visíveis no peito e flancos. Habita rios de correnteza rápida com margens rochosas, geralmente em altitudes mais elevadas. É menos dependente de zonas húmidas abertas do que a maioria dos patos dabbling. É encontrado em florestas ribeirínhas e paisagens de savana com rios adequados. É uma espécie residente e não migratória.
Steller's Eider
O êider-de-steller é o menor dos quatro patos êider, com plumagem elaborada e intrincada nos machos. Os machos têm cabeça branca com olhos verdes marcantes, nuca verde, peito laranja-avermelhado e pontos negros no peito. Cria em pântanos de tundra ártica na Rússia e Alaska. As populações do Alaska colapsaram dramaticamente, levando à sua listagem como ameaçada nos Estados Unidos. As causas do declínio ainda não são totalmente compreendidas.