Order: Pteroclidiformes
Family: Pteroclidae
Recalls a Black-bellied Sandgrouse, with black belly.
During breeding plumage, the male has a deep ocher color on the chest and side of the head. The chin is black and its back is a greenish-gray color with yellow spots. The chest has a dark band (“bib”). The greater coverts are brown and gray with yellow and black lines. The female has a lighter ocher color on the chest and side of the head (less intense than the male). On the other hand, the chin is white and the back is striped with yellow, gray, and black. On the chest, it has two dark bibs. On the wing, the innermost secondaries are striped. The greater coverts are yellow and gray with dark lines. During the eclipse plumage period, the male is more similar to the female, but with a different design on the wing coverts.
It is possible to recognize 3 different ages:
Juvenile specimen: with a light band behind the eye. Back feathers and wing coverts with a cream edge and a brown “V” shaped line. The central tail feathers are short. It is important to note the primaries and primary coverts with a clear tip.
1st-year / 2nd-year specimen: similar in appearance to the adult, but with the three outermost primaries and their juvenile coverts not molted.
Adult specimen: without a light band behind the eye. Back feathers and wing coverts without a brown “V” shaped line. The central tail feathers recognizably long. Primaries and primary coverts without a clear tip.
The Pin-tailed Sandgrouse performs a complete post-nuptial molt, which typically ends in October, acquiring the eclipse plumage. On the other hand, the molt performed by juvenile specimens is quite complete. In this case, they molt all feathers except P10, P9, and P8 along with their corresponding primary coverts. Both types of age have a pre-nuptial molt, between November and March, that includes body feathers to acquire breeding plumage.
Primaries: 10 per wing.
Secundaries: 16-17 per wing.
Rectrices: 14-18.
