Proximal underwing coverts are vermiculated or flecked on adult and most immature males. These feathers are barred on females and on a few immature males. Age Determination of Males Immature tertials are often frayed and faded, usually narrow, and lack the pearly color of adult tertials. By late November immature tertials are replaced by first winter tertials, identical in appearance to adult feathers. At the same time, immature tertial coverts may be replaced by coverts which are broader, unfrayed, and similar to adult coverts and thus differ from adjacent immature coverts, which have not been molted.
Many immature males have light edging on the inner webs of the most distal primary coverts.
Adult males do not show this character. Middle coverts of immatures are narrower and more trapezoidal than those of adults. This type of edging does not occur on the middle coverts of adult males. Tertial coverts of immatures are often frayed, faded, and narrow, and the two most proximal often lack the white of the speculum bar. As with males, greater tertial coverts of immatures may be replaced.