Appearing as an ordinary black
or gray bird when light hits a full grown adult male is obvious
how they get their name. The black areas become brilliant deep
purple in color.
It take a male 3 years to reach
adulthood and acquire their plumage. Male martins molt in to
their purple plumage during their second Wintering season in
Brazil.
Until a male martins second
season molt they are often confused to be a mature female. Males
seem to have darker heads than their female counterparts.
Sub adult male
martin have a darker head & back and lighter under parts. Gray
on the forehead and often have a few dark feathers showing on
the breast.
Sub Adult Male
Females tend to have
more purple on their crown and nape, ( shoulders), back
and rump than young females.
Molt starts in late
summer and stops during migration then resumes at winter
roost where plumage change occurs.