Fulvous Whilsting-Duck
Black-bellied hybrid
*Very variable
Partial or thin white eye-ring
Bill is partly Blue/black and Pink, typically pink at the base
Underside typically chestnut whether as black
The face is a perfect tan color, almost like a West Indian Whistling Duck.
Sound
High-pitched two-part whistle, kit-tee or pee-chee
Short high-pitched squeals
Hostile kee repeated >4 times rapidly
Chatter cup-cup-cup-cup
Adults are fairly easy to distinguish from other ducks. Birds are most similar to Black-bellied juveniles. Told apart by overall more rufous coloration and buffy belly with white undertail coverts.
Different Xeno Canto links
kit-tee/pee-chee: https://xeno-canto.org/649366
Squeals(maybe) https://xeno-canto.org/257268
cup-cup-cup-cup https://xeno-canto.org/48071
Sight
Long-necked duck
Appears taller than Black-bellied when they stand up
Overall buffy cinnamon coloration
Undertail coverts white
Blackish brown back, tail and wings
Buff flanks
Tawny cinnamon upperparts get more “rich” on the head
Chin pale white
Black bill and legs
Wings more round and broader than other ducks
Slow wing beat
Legs behind tail in flight
Immature smaller by a bit
Immature sometimes have more white or chestnut on flanks or back
Juvenile young is similar to Black-bellied but with a less yellow coloration
Juvenile young have distinct black facial markings
Note cinnamon wing patch, white chin, undertail coverts and overall cinnamon buffy colored body.
See Bill and upperpart coloration with a white chin.
Juvenile birds, some more extensive chestnut and white on flanks
Note duller yellow young, distance black markings.
Gallery
Note most ID facters, black back, white chin, buffy flanks, chestnut head.