Mariana Swiftlet vs Great Dusky Swift
Aerodramus bartschi comparé à Cypseloides senex
Side-by-Side Comparison
| Attribut | Mariana Swiftlet | Great Dusky Swift |
|---|---|---|
| Nom scientifique | Aerodramus bartschi | Cypseloides senex |
| Ordre | Caprimulgiformes | Caprimulgiformes |
| Famille | Apodidae | Apodidae |
| Statut de conservation | Vulnerable | Least Concern |
| Longueur | — | — |
| Envergure | 17,7 cm (7.0 in) | 33,8 cm (13.3 in) |
| Poids | 7,25 g (0.26 oz) | 83,0 g (2.93 oz) |
| Régime alimentaire | Entirely airborne insectivore; feeds on minute flying insects and web-dispersing spiders over open habitats. | Feeds on aerial plankton of tiny insects and spiders; entire diet captured during non-stop aerial … |
| Taille de la couvée | 1 | 1-2 |
| Population Trend | — | — |
Habitat Comparison
Song & Call Comparison
Mariana Swiftlet
Very high, thin twittering; tiny and high-pitched; 'tsit-tsit' over Guam and Saipan; audible echolocation clicks in cave roosts; endangered; vocal mainly near nesting caves
Great Dusky Swift
Loud, churring trill; harsher and louder than other Cypseloides; calls over Iguacu Falls and major Neotropical waterfalls; buzzy 'bzzzt-bzzzt' in aerial groups
Geographic Range & Migration
Mariana Swiftlet
Endemic to the Mariana Islands (Guam, Saipan, and adjacent islands). Resident in forested areas; nests in limestone caves. Endangered on Guam.
Great Dusky Swift
Found in eastern South America from Venezuela and the Guianas south to Bolivia and Paraguay. Resident near rocky cliffs and waterfalls.
Statut de conservation
Mariana Swiftlet
Great Dusky Swift
How to Tell Them Apart
Mariana Swiftlet
Tiny; dark brownish-black upperparts; pale grey-buff rump band; underparts pale whitish-grey; forked tail; Mariana Islands endemic and vulnerable; very small for the genus with concolorous brownish tone and subdued rump …
Great Dusky Swift
Very large; entirely dark sooty-brown with pale grey forehead and chin scaling; slightly paler underparts; broad wings; largest Cypseloides swift; South American waterfall specialist with dusky uniform plumage and imposing …
About These Birds
Mariana Swiftlet
A small swiftlet (10-11 cm) endemic to the Mariana Islands of the western Pacific (Guam, Saipan, Rota, Tinian). Dark brown plumage. Aerial insectivore. Colonial cave nester using echolocation. Population severely declined on Guam due to the brown tree snake.
Great Dusky Swift
A large swift (18-20 cm) of southeastern Brazil, eastern Paraguay, and northeastern Argentina. Dark sooty-brown plumage. Aerial insectivore, foraging over forested gorges and waterfalls. Nests in large colonies behind waterfalls. The largest member of the genus Cypseloides.