Non-breeding adults have paler and browner upperparts, and a white nape collar.
There is a distinctive band of larger thorns running along the midline of the back, from the nape to the caudal peduncle.
The red-billed teal is 4348 cm long and has a blackish cap and nape, contrasting pale face, and bright red bill.
Juveniles have brownish crowns, lemon tinged nape and an orange base of bill.
In the latter subspecies the face and nape are a paler brown.
The maidens tie their tresses into a roll and keep it tied just above the nape.
Juveniles are a duller version of the adult but have more feathers on the nape.
The crown, nape, ear coverts, hindneck, and sides of neck are dark grey, and lores and chin are a grey-black.
